Influence Of Particle Size Distribution Research Articles

Study on the Influence of Particle Size Distribution on the Separation of Pyrite from Coal Gangue by Jigging

Study on the Influence of Particle Size Distribution on the Separation of Pyrite from Coal Gangue by Jigging

Research on the density of underwater sand and gravel fillings based on geotechnical centrifugal tests

The density of underwater dumping materials plays a major role in cofferdam engineering designs. However, it is difficult to accurately measure the density of underwater dumping materials. This study investigated the influence of particle size distribution of granular materials on the density of underwater filling materials. Considering the underwater dumping project of a hydropower station dam in the Han River as the prototype condition, several underwater dumping density centrifugal tests were conducted on sand gravel and sand mixtures. Based on the CKY200 large-scale geotechnical centrifuge, a single-embankment vertical-blockage underwater filling test device in a centrifuge field was developed. The results demonstrated the relationship between the compactness of the dumping body and the grading of loose particles, depth of dumping, and height of the upper loading. This indicates that the underwater filling material has a higher compactness and can reach a dense state. When the grading is poor, the compactness decreases. The greater the depth of filling, the greater the compactness. When vertical compression was applied to the upper part of the backfill, the compactness of the backfill, particularly in shallow areas, was significantly improved. These results provide insights for the design and construction of underwater dumping water conservation systems.

Spherical Graphite Anodes: Influence of Particle Size Distribution and Multilayer Structuring in Lithium-Ion Battery Cells

Current research focuses on lithium-ion battery cells with a high energy density and efficient fast-charging capabilities. However, transport limitations, and, therefore, the uniform diffusion of lithium-ions across the electrode layers, remain a challenge and could lead to reduced cell performance. One approach to overcome these transport challenges is the use of subsequently produced two-layer anodes with the particle size variation of spherical graphite (x50 = 18 µm; x50 = 11 µm). Thereby, a defined pore network is created, which reduces the ionic resistance and ensuring improved fast charging capabilities. The analysis focuses on the evaluation of electrode properties and the electrochemical performance. By examining the pore size distribution of the anodes, it has been found that during the manufacturing of the two-layer anodes, carbon black and binder particles are transported into the existing microstructure of the lower layer, resulting in localized densification between the anode layers. This could also be supported by color measurements. This effect also extends to electrochemical investigations, with electrochemical impedance spectroscopy showing significantly lower ionic resistances in all two-layer anodes. Reduced ionic resistance and tortuosity near the separator due to absorption effects enhance the ion diffusion and have a direct impact on anode performance. Cell ageing analysis showed a significant capacity decrease of almost 15 mAh g −1 in the single-layer references only, in contrast to the stability of the two-layer anodes. This could also be attributed to the reduced ionic resistance and active counteraction of binder migration. In conclusion, this study highlights how subsequently produced two-layer anodes significantly shape the electrode properties and cell performance of lithium-ion batteries.

Influence of particle size distribution on dielectric, electrical, and microstructural properties of aerosol-deposited Ga2O3 film for advanced electronic device

Gallium oxide (Ga2O3) films have been the subject of recent scientific and technological research, owing to their outstanding characteristics. In this study, a rapid and efficient aerosol deposition (AD) process was utilized to produce Ga2O3 films. The effect of the particle size distribution (PSD) of the columnar or plate-like Ga2O3 starting powder on the dielectric, electrical, and microstructural properties of the films was also investigated. The dielectric constant and loss tangent of polycrystalline β-Ga2O3 films fabricated using AD with narrow PSD Ga2O3 powder were 10 and 6.7% at 10 kHz, respectively. In contrast, the films composed of a wide PSD powder exhibited a dielectric constant of 18 and a loss tangent of 3.6%. The leakage current densities of 1.77 × 10−5 and 6.63 × 10−7 A/cm2 at 5 V of the films using narrow and wide PSD powder were observed, respectively. In addition, the breakdown electric fields of the Ga2O3 films with narrow and wide PSD powder were 1.15 and 1.06 MV/cm, respectively. Qualitative and quantitative analyses of the surface and inner microstructure were conducted to elucidate the differences in film characteristics according to the PSD. Consequently, a wider PSD enables the production of relatively denser and flatter high-quality films owing to enhanced hammering and crush effects. These results suggest potential applications of Ga2O3 films fabricated using AD in various fields, such as capacitors, power semiconductors, and sensor devices.

Numerical study of the effect of particle size dispersion on order within colloidal assemblies

The formation of colloidal crystals is of interest in many fields, especially because of their optical properties. These properties are dictated by the colloidal arrangement. It is known that introducing particles with different sizes can change the structure of crystals and thus their resultant optical properties. To better understand how specific arrangements of particles can be obtained, a detailed understanding of the formation mechanisms is needed. The influence of particle size distribution on the formation of colloidal crystals is studied by means of Brownian dynamics simulations performed with different types of interaction potentials. Crystal formation is first analyzed in systems containing homogeneous particles, then in systems with a size distribution.It is shown that the interaction potential has a strong influence on the colloidal arrangement. For homogeneous particles, the width of the potential well affects the aggregate shape: a larger width leads to more elongated structures. When a size distribution is introduced, aggregation becomes more difficult since the number of isolated colloids increases, and aggregates become disordered regardless of the interaction potentials. Depending on the interaction potential, differences in the aggregates are observed. These differences are rationalized in terms of the specific features of the different potentials.

Recycling alkali activated slag into artificial aggregate: Influence of particle size distribution of the starting material on granulation

Wet granulation is a potential method to develop artificial aggregates. In this paper, the granulation of recycled alkali-activated slag powders with different particle size (d50 ranging between 12.9–127.7 μm) distributions were investigated in order to find how these affect on the engineering properties of the artificial aggregates. Blast furnace slag was added as co-binder in 10–30 wt. % during the granulation process and to enhance the properties, especially mechanical strength. The results show that the particle size of the raw material significantly affects the engineering properties of the produced aggregates, such as the crushing force (19–131.8 N), bulk density, water absorption, porosity and microstructure of the granules. The results show that granulation is a promising method to recycle alkali-activated materials as lightweight aggregates to replace natural aggregates.Graphical

Influence of particle size distribution on biocarbonation method produced microbial restoration mortar for conservation of sandstone cultural relics

Biocarbonation of reactive magnesia based on microbially induced carbonate precipitation (MICP) process is a sustainable geotechnical reinforcement technology for strength development and permeability reduction. This method can be used to produce microbial restoration mortar (MRM) for the application of stone cultural relics restoration. In this paper, the influence of particle size distribution on the strength and porosity of MRM was examined. By mixing fine and coarse sandstone powder in various proportions, nine different particle size distributions were obtained to investigate the restoration performance, including the unconfined compressive strength (UCS), porosity, and color difference. The results indicate that the well-graded particle size distribution can lead to the UCS improvement and porosity reduction of MRM. The findings also imply that adding fine sandstone powder to the coarse sandstone powder can provide extra bridging contacts within the soil matrix. These bridging contacts can be easily connected by the precipitated hydrated magnesium carbonates (HMCs) minerals, consequently resulting in more effective bonding and filling within the pore matrix. The microstructural images of MRM confirm the formation of HMCs, which exhibited a dense network structure, filling out the gap and bonding the sandstone powders. Furthermore, the microbial restoration mortar showed a high weather resistance to dry-wet cycles, acid rain, and salt attack, which is attributed to better stability and strength of HMCs than the original calcic cemented minerals in sandstone.

Numerical simulation of disperse process of fuel‐air explosive based on the computational fluid dynamics

AbstractThe formation process of fuel cloud is easily affected by the material properties of fuel mixture and the structural qualities of manufacture. The spread region of fuel cloud plays an important role in the damage performance of FAE bomb. However, there are not sufficient simulation study on the disperse process, lacking a useful model for calculating the fuel cloud size due to the physical complexity in disperse process. In this work, a FAE bomb was designated at first and an experiment was carried out to measure the fuel cloud diameters. And then a computational model was established to illustrate the formation process of fuel cloud. This computational model consisted of an explosion dynamics model in the near‐field stage and a fluid dynamics model in the far‐field stage. Furthermore, multiphase turbulence flow, discrete phase and species chemical transportation were incorporated in the fluid dynamics model. The results showed that good agreements were yielded by comparison of the simulation results and experimental data for the fuel cloud diameters. The fuel cloud diameter at 220 ms was 9.11 m for simulation and 9.37 m for experiment. Additionally, it was also discussed the influence of particle size distribution on the formation process of fuel cloud. Larger particles were more likely to aggregate at the outside region of fuel cloud due to individual inertial influence. This study can provide an effective computation model for evaluation of the fuel cloud region, which can be worthwhile in understanding the physical mechanism of disperse process.

Analysis of the dissolution of phosphate ore particles in phosphoric acid: Influence of particle size distribution

A first principles model is developed to describe the dissolution mechanism of phosphate ore particles in a solution of phosphoric acid. It is based on mass balance equations along with hydrodynamic and kinetic relations, combined with a shrinking core model with product removal. Furthermore, non-uniform size of ore particles is accounted for using particle size distributions (PSDs) (i.e., Rosin-Rammler-Bennett, Gamma, Gate-Gaudin-Schuhmann distributions). Moreover, a coefficient of variation (CV) is used to quantify the influence of the PSD shape on the model predictions at different temperatures, acid concentrations and stirring speeds. The resulting three-phase (i.e., solid particles, liquid film surrounding the particles and liquid bulk) involves several unknown parameters. A global estimability analysis is therefore carried out to determine the estimable parameters from the available experimental data. The most estimable parameters are then identified from measurements of the particle conversion fraction mainly collected from the literature. The optimal values of the estimable unknown parameters are very consistent with the values in the literature and the predictions show good agreement with the experimental data. Finally, the computed activation energy of the dissolution reaction is very low indicating that diffusion is the rate limiting step of the dissolution process.

Investigating the suitability of North Dakota fly ash as fluid loss reducing additive in densified water-based drilling fluid

Fluid loss circulation control during drilling operations is becoming more challenging as exploration moves from conventional to unconventional energy resources. The process of controlling filtrate loss during drilling operation necessitates the right design of drilling fluid that is capable to build an impermeable thin filter cake layer and permit a loss of a reasonable amount of filtrate volume into the formation. It is essential to understand the dynamics that play out between particle morphology of drilling mud additives to assess the sealing efficiency of the loss-reducing additives. As a result, a lot of materials were suggested as fluid loss-reducing materials, which also give thin filter cake thickness. This study investigates the suitability of a coal-fired plant waste (fly ash), as an alternative supplement for filtration agents to improve the quality of the filter cake layer that is built using ilmenite (FeTiO3) derived densified drilling fluid. The ilmenite-derived densified water-based mud samples containing 0, 1, 2, and 3 lb./bbl of fly ash were investigated. To gain an understanding of the pozzolanic influence of class C fly ash on ilmenite-weighted water-based mud, tests were conducted at reservoir conditions according to API specifications. The results from drilling fluid tests were benchmarked against the API standard range of values and contrasted with a control drilling fluid with no-fly ash added. It has been found that mud samples that include fly ash have better filtration properties. The openings in the filter cake were sealed by the amorphous structured fly ash particles, which created an impermeable filter cake. In Mud-4 and Mud-5, where the filtrate volume was reduced by 75% and 79%, respectively, the influence of particle size distribution to form a good sealant and a further reduction in filtrate loss was observed.

Influences of particle size distribution and fines content on the excess pore water pressure generation of sand-silt mixtures under cyclic loading

The mechanical behaviors of binary mixtures are different from that of uniform soils. However, experimental studies on the dynamic responses of sand-silt mixtures considering the combined effects of fines content (FC) and host sand gradation are limited in the literature. In this paper, an experimental program was designed concerning five binary mixtures with three grain size ratios (Rd) and three sand uniformity coefficients (Cus) for investigating the effects of fines content and host sand gradation on both the liquefaction resistance and the excess pore water pressure (EPWP) generation of sand-silt mixtures. Results show that the effect of FC on the liquefaction resistance of sand-silt mixtures depends on relative density (Dr), grain size ratio, and sand uniformity coefficient. The liquefaction resistance of sand-silt mixture can be uniquely characterized by the equivalent relative density Dr* regardless of FC, Dr, and host sand gradation. Relationship between the EPWP ratio Ru and the cycle ratio N/NL for the sand-silt mixtures can be well expressed by the Seed model, which is significantly affected by cyclic stress ratio (CSR), FC, and Dr but insensitive to the change of host sand gradation. A trained artificial neural networks (ANN) model is conducted to predict the fitting parameter β of the Seed model with a maximum difference of 25% between the predicted and measured values. Moreover, there is an arctangent relationship between Ru and shear strain amplitude γa of each specimen, and the fitting parameter A for the relationship is sensitive to the particle size distribution and stress amplitude. A unique relationship between a density-corrected parameter A/Dr* and CSR is proposed regardless of FC and host sand gradation.

Quantitative evaluation of thermal conductivity of earth materials with different particle size distributions

The thermal conductivity of earth materials is closely related to density and particle size distribution. However, existing studies on the thermal conductivity of these materials have neglected the influence of particle size distribution, leading to inconsistent results and hindering the quantitative evaluation of the thermal performance of earth materials. To promote the utilization of earthen building materials in energy-efficient design, this study establishes a quantitative assessment model for the thermal conductivity of earth materials, grounded in their microscopic agglomeration morphology and pore structure properties, through experimental analyses and theoretical derivation. The average prediction error of the model is about 1.77%, which improves the precision of characterizing the thermal conductivity of earth materials. Utilizing this model, the impact of clay, sand, and gravel content on the thermal conductivity of earth materials was investigated quantitatively. The findings reveal that the thermal conductivity of earth materials attains its minimum value when the sand content is approximately 37.3%, and diminishes progressively with tthe increase of the clay content. The above findings offer a theoretical foundation for optimizing the thermal performance and fabrication process of earth materials, thereby fostering the integration and application of these materials in sustainable building systems.

Influence of Particle Properties on Filter Cake Compaction Behavior under Oscillatory Shear

Filter cake compaction is a common method for mechanical deliquoring of compressible filter cakes. In addition to the conventional squeezing compaction method, applying oscillatory shear to filter cakes at low pressure is an alternative compaction process in cake filtration. While basic differences in terms of compaction success have already been identified for various materials, a systematic analysis of the influence of material properties on compaction behavior under oscillatory shear is missing. The present work addresses the influence of particle size distribution and increasing particle agglomeration on the compaction success of oscillatory shear to further clarify the process knowledge and applicability. The compressibility achieved by this technique was investigated for calcium carbonate materials with various particle size distributions. The results show that the compaction potential increases from 17.3% for the coarsest material (x50,3 = 23.5 μm) to 26.6% for the finest material (x50,3 = 2.3 μm) with decreasing mean particle size. The more widely distributed material exhibits a higher compaction potential of 21.7% compared to 18.4% for the narrowly distributed material. Increasing particle agglomeration to improve the slurry filterability does not affect the achievable compaction states of the material by vibration compaction at sufficiently high energy input.

Effect of grain size distribution on the shear properties of sand

In this study, we investigated the effect of particle size distribution on the shear properties of sand. Direct shear tests were conducted using four types of sand samples with different particle size distributions obtained from standard sand produced by Xiamen ISO Co. Ltd. The results show that the influence of particle size distribution on the internal friction angle was significant. Typically, the internal friction angle increases with increasing the coefficient of non-uniformity (Cu) and decreasing the curvature coefficient (Cc). The discrete element results show that the initial particle size distribution significantly affects the porosity, coordination number, and particle slide fraction. In addition, the grey relation analysis revealed that the sliding fraction and coordination number have the greatest correlation with the internal friction angle. The research results of this study help to understand the changes in particle contact, internal stress, and particle sliding during the shear failure process of sand.

Influence of particle size distribution on properties of fired refractory bricks

.

Effect of particle size distribution on monotonic direct shear characteristics of geotextile/geogrid-calcareous sand interface

Geosynthetics reinforced soil techniques are adopted to reinforce the calcareous sand foundations to improve the stability of the revetment structures in coral reefs. In this research, the influence of particle size distribution on the interaction characteristics of the geotextile/geogrid-calcareous sand (GT/GG-CS) and unreinforced calcareous sand (URCS) interface is investigated through a series of large-scale monotonic direct tests. The interface interaction mechanism of GT/GG-CS and URCS is determined. The results show that under different particle size distributions and normal stresses, the dilatation curves of the GT/GG-CS and URCS interface mainly show the development patterns of contraction-dilatation-contraction, contraction-dilatation, and contraction. Additionally, embedding geogrid/geotextile in calcareous sand can significantly improve peak cohesion. For coarse-grained calcareous sand, the peak cohesion increases by 3.68 times (Geogrid-calcareous sand interface) and 2.41 times (Geotextile-calcareous sand interface). Overall, using coarse-grained calcareous sand as filler improves the stability of dredger-fill calcareous sand foundations and revetment-reinforced soil engineering.

Influence of powder particle size distribution on microstructure and mechanical properties of 17-4 PH stainless steel fabricated by selective laser melting

This study explores the influence of particle size distribution (PSD) and heat treatment on 17-4 PH stainless steel fabricated by selective laser melting, which greatly improved the elongation of the material on the basis of ensuring the strength. Scanning electron microscope and electron backscattering diffraction were used to characterize the microstructure of 17-4 PH stainless steel. 17-4 PH stainless steel PSD+ and PSD− samples have obtained equiaxed grain, and the internal tissue distribution in PSD+ sample crystals is uneven. By reason of the gas in the large partials of PSD+ powder falling into the size distribution of 49 μm–58.9 μm, it was difficult to escape during the SLM process, which reduced the material density and mechanical properties. Compared with the PSD+ specimens, the tensile strength, hardness and elongation of the PSD− specimens are increase to 345.2 HV, 938.7 MPa, and 22%, respectively. This trend is retained after heat treatment, and the surface hardness, tensile strength and elongation rate of PSD− HT specimens, which are 5.3%, 5.4% and 12.9% higher compared with the PSD+ HT specimens, respectively.

Influence of Particle Size Distribution on Properties of Fired Refractory Bricks

Influence of Particle Size Distribution on Properties of Fired Refractory Bricks

Influence of particle size distribution on espresso extraction via packed bed compression

Espresso extraction is a diffusion-convection process involving both intra-granular pores, and the intergranular pores of the packed bed. Bed hydrodynamics and overall end-cup quality are governed by the bulk porosity, set by the dry coffee bed compression before extraction. In this work, the impact of the initial bed compression on the water permeability during espresso extraction is studied. Coarse fractions of the bimodal coffee particle size distributions were characterized by the particle mean size α and the size uniformity β of the distribution. It was found that under the same axial compression lower bed porosities were obtained with decreasing size uniformity β, even at larger mean size α. A model was developed to predict the dry packed bed porosity. Extraction experiments confirmed that low permeability desired during espresso brewing was found not to be exclusive to distributions with low mean particle sizes. Rather, it can also be achieved by tuning compression force, α, and β together. A modified Kozeny-Carman expression was derived to explain and predict the observed permeability results. • Study of bed compression and espresso extraction impacted by particle size distribution. • Compression and extraction experiments in modified espresso machine. • Bed compression model developed as function of size distribution for roasted coffee. • Lower packed bed porosities achieved with lower size uniformity distributions. • Experiment permeabilities were successfully predicted with modified Kozeny-Carman expression.

An Approach to Quantifying the Influence of Particle Size Distribution on Buried Blast Loading

Buried charges pose a serious threat to both civilians and military personnel. It is well established that soil properties have a large influence on the magnitude and variability of loading from explosive blasts in buried conditions. In this study, work has been undertaken to improve techniques for processing pressure data from discrete measurement apparatus; this is performed through the testing of truncation methodologies and the area integration of impulses, accounting for the particle size distribution (PSD) of the soils used in testing. Two experimental techniques have been investigated to allow for a comparison between a global impulse capture method and an area-integration procedure from a Hopkinson Pressure Bar array. This paper explores an area-limiting approach, based on particle size distribution, as a possible approach to derive a better representation of the loading on the plate, thus demonstrating that the spatial distribution of loading over a target can be related to the PSD of the confining material.