Effect Of Particle Size Distribution Research Articles

Macro-Micro Mechanics of Granular Soils Under Shear Considering Coupled Effects of Particle Size Distribution and Particle Morphology.

This paper investigates the effects of particle morphology (PM) and particle size distribution (PSD) on the micro-macro mechanical behaviours of granular soils through a novel X-ray micro-computed tomography (μCT)-based discrete element method (DEM) technique. This technique contains the grain-scale property extraction by the X-ray μCT, DEM parameter calibration by the one-to-one mapping technique, and the massive derivative DEM simulations. In total, 25 DEM samples were generated with a consideration of six PSDs and four PMs. The effects of PSD and PM on the micro-macro mechanical behaviours were carefully investigated, and the coupled effects were highlighted. It is found that (a) PM plays a significant role in the micro-macro mechanical responses of granular soils under triaxial shear; (b) the PSD uniformity can enhance the particle morphology effect in dictating the peak deviatoric stress, maximum volumetric strain, contact-based coordination number, fabric evolution, and shear band formation, while showing limited influences in the maximum dilation angle and particle-based coordination number; (c) with the same PSD uniformity and PM degree, the mean particle volume shows minimal effects on the macro-micro mechanical behaviours of granular soils as well as the particle morphology effects.

Investigating the effect of particle size distribution and complex exchange dynamics on NMR spectra of ions diffusing in disordered porous carbons through a mesoscopic model.

Ion adsorption and dynamics in porous carbons are crucial for many technologies, such as energy storage and desalination. Nuclear magnetic resonance (NMR) spectroscopy is a key method to investigate such systems thanks to the possibility of distinguishing adsorbed (in-pore) and bulk (ex-pore) species in the spectra. However, the large variety of magnetic environments experienced by the ions adsorbed in the particles and the existence of dynamic exchange between the inside of the particles and the bulk renders the interpretation of the NMR experiments very complex. In this work, we optimise and apply a mesoscopic model to simulate NMR spectra of ions in systems where carbon particles of different sizes can be considered. We demonstrate that even for monodisperse systems, complex NMR spectra, with broad and narrow peaks, can be observed. We then show that the inclusion of polydispersity is essential to recover some experimentally observed features, such as the co-existence of peaks assigned to in-pore, exchange and bulk species. Indeed, the variety of exchange rates between in-pore and ex-pore environments, present in experiments but not taken into account in analytical models, is necessary to reproduce the complexity of experimental NMR spectra.

Metal-organic framework-based tunable platform for the immobilization of lipase with enhanced activity in non-aqueous systems.

Nowadays, metal-organic frameworks (MOFs) have been emerged as an efficient platform for enzyme immobilization due to their high porosity, tunability, and chemical versatility. In this study, a series of hybrid lipase@NKMOF-101-M (M = Mg, Mn, Zn, Co, or Ni) biocatalysts were constructed through a facile in situ encapsulation method, and the encapsulation and immobilization of lipase in MOFs were carefully validated. The catalytic activity of lipase@NKMOF-101-Mn was 2-fold higher than that of lipase@ZIF-8 and 3-fold higher than that of lipase@MCM-41 due to its excellent dispersibility and hydrophobicity in hexane. The reduced Km value demonstrated a superior affinity of lipase@NKMOF-101s toward to the substrate in non-aqueous reaction system. Moreover, the effects of MOF particle size, metal ions, and enzyme distribution on the catalytic performance of the immobilized lipase were systematically investigated. The results demonstrated that as the particle size of lipase@NKMOF-101s decreased, the apparent enzyme activity increased dramatically. Metal ions in MOFs exhibited activation effect toward to enzyme activity and an approximate 12-fold increase in activity was achieved when transesterification was performed using lipase@NKMOF-101-Mn compared with free lipase. Notably, lipase@NKMOF-101-Co and lipase@NKMOF-101-Ni exhibited substrate selectivity owing to the specific distribution of the lipase in the MOF carriers. Lipase@NKMOF-101s can maintain >80 % of its initial activity even after 5 recycles and a long-term storage (30 days). Consequently, NKMOF-101 is a tunable and sustainable platform for the construction of enzyme@MOFs biocatalysts with superior catalytic performance.

Assessing the effects of flour particle size distribution to improve dough rheological properties and whole wheat rusks characteristics: A case study on industrial pilot plant

Assessing the effects of flour particle size distribution to improve dough rheological properties and whole wheat rusks characteristics: A case study on industrial pilot plant

Effect of particle gradation and rock block content on soil-rock mixture shear strength parameters

Soil-rock mixture (SRM) is highly inhomogeneous and loose geomaterial found in the quaternary formation, composed of a certain percentage of rock blocks, fine-grained soil, and pores. In Peninsular Malaysia, SRM can commonly be found in the granitic formation covering the mountainous areas where slope failures are prone to occur due to deep tropical weathering, heavy rainfall, and steep terrain. Numerous research studies have been conducted to investigate the mechanical behaviour of SRM, especially the influence of rock block content. However, the effect of particle size distribution has been studied in limited detail. This study uses sieve analysis, specific gravity, compaction, and direct shear box tests to determine the shear strength parameters of weathered type SRM with particle size distribution. The sample collected was divided into well-graded, poorly-graded, and gap-graded types of particle size distribution with 30%, 50%, and 70% rock block content, respectively. The percentage of rock block content is crucial in controlling the shear strength parameters. The specific gravity, dry density, optimum moisture content, and estimated porosity values measured show a considerable difference when the particle size distribution (PSD) and rock block content change. The findings also show that for a well-graded SRM, cohesion and friction angle values show a non-linear relationship against the rock block content. Meanwhile, as the rock block content increases, the cohesion decreases and inversely has an increment of friction angle for poorly-graded SRM. In contrast, the cohesion of gap-graded SRM increases when the rock block content increases. Hence, by understanding the influence of particle size distribution on the shear strength parameters of SRM, a better evaluation can be made in designing slope hazard mitigation.

Impact of grinding media shape on the dissociation characteristics and flotation behavior of coking coal middlings

The effective dissociation of feed materials has a major impact on the mineral flotation recovery performance in the mineral processing field. Coking coal middlings is difficult to be effectively dissociated due to its complex internal gangue distribution characteristics. The aim of this paper is to compare and evaluate the performance of ball versus hexagonal prism media for the coking coal middlings comminution by point contact and line-surface contact. The results of the grinding tests show that hexagonal prism could result in a more uniform coal particle size distribution, less over-grinding and better selective dissociation effect comparing with ball. The results of the particle shape coefficient indicate the hexagonal prism milled product has a sphericity (Rs) of 0.90 and an elongation (EW) of 1.69, which is more slender than the ball milled product (Rs = 0.94, EW = 1.47). Flotation tests showed that the hexagonal prism milled product was more hydrophobic with a wrap angle of 185° compared to the ball milled product at 121°. Meanwhile, the TSI value of the hexagonal prism milled product is 80.500, which is lower than the 82.608 TSI value of the ball milled product, indicating that the flotation system of the hexagonal prism mill product is more stable. Under the same flotation test conditions, the combustible matter recovery rate of the hexagonal prism milled product was 5.08 % higher than that of the ball milled product.

Permeability modulation of Fe-Ni/nanoparticle (Ni, Zn) soft magnetic composites

In this study, we investigated how adding nanopowders to a micropowder affects the packing fraction and permeability. The micropowder used was a Fe-Ni crystalline alloy, which was sieved to less than 38 μm to minimize the effect of particle size distribution. The nanopowders, magnetic Ni and nonmagnetic Zn, were added to the Fe-Ni at weight ratios of 95:5, 90:10, 85:15, and 80:20. The results showed that the permeability of Fe-Ni was higher when sieved to 38 μm compared to the overall particle size. When the magnetic Ni nanopowder was added to the Fe-Ni powder sieved to 38 μm, both the packing fraction and permeability increased up to a ratio of 85:15 and then decreased. On the other hand, when the nonmagnetic Zn nanopowder was added, the packing fraction increased up to a ratio of 85:15 and then decreased, while the permeability continued to decrease.

Study on the influence of aerosol atomization by ultrasonic atomization on coal spontaneous combustion

ABSTRACT Influenced by the complex environment and the nature of process materials in goaf, the prevention and control of spontaneous combustion of coal (CSC) in the deep part of goaf were facing many difficulties. To investigate the performance of ultrasonic atomized aerosols, a series of atomization experiments were conducted using a self-developed ultrasonic atomization device. The main conclusions are as follows: under the same atomization conditions, the atomized particle sizes of several inhibitors (except PAS-W) are concentrated in the <8 μm range, with a content of more than 88%, indicating that the aerosol particles produced by ultrasonic atomization are small in size and uniform in distribution. Compared with water and MgCl2 inhibitors, aerosol particles produced by PAS-W are less likely to pass through the voids of the coal body, and have poorer permeability and diffusivity. As the temperature increases, the viscosity and surface tension of the inhibitor decrease, and the percentage of aerosol particles with particle size <8 μm produced by ultrasonic atomization is more than 88%, indicating that the atomization effect is improved. After increasing the temperature, the contact angle between PAS-W inhibitor and coal reduces from 54.7° to 40.8°, and the wettability is better. Compared with raw coal, the final temperature of the PAS-W aerosol treated coal sample is delayed 21.86°C, and has significant retarding property. When the wind speed is 3 m/s, the effect of PAS-W aerosol particle generation, permeability, and particle size distribution is the best. The results of the study are of great significance in improving the ultrasonic atomized aerosol fire prevention technology and realizing large-scale CSC prevention in goaf.

Effect of particle size distribution on the thermal conductivity of crushed GMZ bentonite pellet mixtures

Effect of particle size distribution on the thermal conductivity of crushed GMZ bentonite pellet mixtures

The effect of particle size distribution on the collapse of wet polydisperse granular materials

Low-saturation liquid-containing granular materials are commonly encountered in both natural and industrial settings, where interstitial liquids significantly affect the motion of particles, while particle size polydispersity plays a crucial role in determining the level of system cohesion. In this study, the collapse of wet polydisperse granular columns is numerically investigated based on the developed discrete element model, with corresponding dam-break experiments performed to validate our numerical model and methodology. The dependence of the dynamics and flow mobility on particle size distribution is primarily examined, and the underlying mechanisms are also explored by analyzing particle path lengths and average fidelity. Building upon the effective Bond number proposed using the mixing theory, a macroscopic cohesion parameter at the material scale is defined by considering the dependence of the collapse on the system size effect. The relevance of this cohesion parameter in describing different wet polydisperse granular collapses is further validated based on our designed experimental tests and DEM simulations. The approach of constructing the cohesion parameters at different scales can be extended to characterize cohesion effects in more complex wet polydisperse granular flows and describe their associated rheological behaviors.

Interparticle interaction effect on superparamagnetic properties of ferrimagnetic particles

Uncoated and oleic acid coated ferrimagnetic particles are synthesized. Both samples contain similar magnetite particles. Structural characterization of these particles is performed using x-ray diffraction, Fourier transform infrared spectra, dynamic light scattering, transmission electron microscopy and thermogravimetric analysis. Average crystallite size of magnetite is 7 nm. Thickness of oleic acid layer on each magnetite particle is 1 nm. The oleic acid coated sample contains 23% oleic acid. Temperature dependence of the zero field cooled susceptibility curve of the uncoated magnetite particles peaks at 120 K. The zero field cooled and the field cooled susceptibility versus temperature curves bifurcate at 195 K. The peak temperature and the bifurcation temperature of the system decrease due to the oleic acid coating. The inverse susceptibility does not vary linearly with temperature in high temperature region. Magnetization versus applied magnetic field data at 250 K are analyzed in different ways to study the interparticle interaction effect on magnetization. We find that the interparticle interactions affect the magnetization process of ferrimagnetic nanoparticles.

Numerical study of a chemical looping combustion system: Effects of fuel type and particle size distributions on the operating performance

Chemical looping combustion (CLC) using biomass offers a promising pathway for achieving negative carbon emissions. However, the different properties of coal and biomass affect reaction performance, which has not been fully explored in the CLC system. Additionally, the effects of particle size distributions (PSDs) of solid fuels and oxygen carriers (OCs) are inadequately addressed. In this study, a 3D reactive model using the computational particle fluid dynamics (CPFD) method is developed to investigate the effects of PSDs of both solid fuels and oxygen carriers on operating performance with coal and biomass as fuels. Results indicate that the average residence time in FR of coal and biomass particles is 0.86 s and 0.68 s, respectively, but biomass outperforms coal in reaction efficiency. For coal-fueled CLC, the average residence time is 0.46 s for coal particles with diameters of 100–200 μm, whereas it reaches 0.86 s for coal diameters of 300–700 μm. However, the reaction performance is better with smaller coal sizes due to char gasification being the rate-limiting step. In comparison, for biomass-fueled CLC, the reaction efficiency remains consistent across various particle sizes under the specified conditions due to the rapid release of volatile components and the low content of char. Additionally, it is found that the OC conversion ratio is mainly determined by their residence time in the zones with relatively higher concentrations of the combustible gas in FR. Employing OCs with overly wide PSDs such as 300–800 μm can compromise the material seal above the AR, increase the risk of gas leakage and decrease the separation efficiency of the inertial separator.

Effect of particle size distribution and content of limestone powder on compressive response of high-early-strength cement mortars

This study examined the effect of particle size distribution and content of limestone powder on the compressive response of high-early-strength portland cement mortars cured either in water or under ambient conditions. Nineteen mortar mixtures were classified into three groups based on the particle size distribution of the pulverized limestone powders: L (blaine = 3467 cm2/g), M (blaine = 4710 cm2/g), and H (blaine = 5764 cm2/g). The design equations for the compressive strength gain rates and stress–strain relationship of ordinary portland cement (OPC) concrete were adapted for the present mortars. The test results revealed that the 28-d compressive strength (fc′) of the mortars tended to decrease with an increase in limestone powder content, even for mortars containing 5 % limestone powder with small particle sizes. This contrasts with the common trend of the positive effect of limestone powder on the compressive strength of OPC concrete up to a certain substitution level. Furthermore, mortars containing finer limestone powders exhibited a greater rate of decrease in fc′, regardless of the curing conditions. The modified equations show promise for reliably assessing both the compressive strength gain rates at different ages and the stress–strain behavior of high-early-strength portland cement mortars containing limestone powders.

Effects of Powder Reuse and Particle Size Distribution on Structural Integrity of Ti-6Al-4V Processed via Laser Beam Directed Energy Deposition

In metal additive manufacturing, reusing collected powder from previous builds is a standard practice driven by the substantial cost of metal powder. This approach not only reduces material expenses but also contributes to sustainability by minimizing waste. Despite its benefits, powder reuse introduces challenges related to maintaining the structural integrity of the components, making it a critical area of ongoing research and innovation. The reuse process can significantly alter powder characteristics, including flowability, size distribution, and chemical composition, subsequently affecting the microstructures and mechanical properties of the final components. Achieving repeatable and consistent printing outcomes requires powder particles to maintain specific and consistent physical and chemical properties. Variations in powder characteristics can lead to inconsistencies in the microstructural features of printed components and the formation of process-induced defects, compromising the quality and reliability of the final products. Thus, optimizing the powder recovery and reuse methodology is essential to ensure that cost reduction and sustainability benefits do not compromise product quality and reliability. This study investigated the impact of powder reuse and particle size distribution on the microstructural and mechanical properties of Ti-6Al-4V specimens fabricated using a laser beam directed energy deposition technique. Detailed evaluations were conducted on reused powders with two different size distributions, which were compared with their virgin counterparts. Microstructural features and process-induced defects were examined using scanning electron microscopy and X-ray computed tomography. The findings reveal significant alterations in the elemental composition of reused powder, with distinct trends observed for small and large particles. Additionally, powder reuse substantially influenced the formation of process-induced defects and, consequently, the fatigue performance of the components.

Effect of Grist Particle Size Distribution and Wort Turbidity on Ester Composition of Malt Whisky New Make Spirit

The parameters used during milling of malt have considerable implications for the turbidity of wort collected during lautering, and wort turbidity has previously been demonstrated to impact ester development by yeast (during fermentation of brewer’s wort). The present research assesses the impact of milling regime and wort turbidity on congener development during production of malt whisky new make spirit. New make spirit was produced from pot still malt prepared with a disc mill under differing milling regimes (mill gap: 0.5–1.5 mm; laboratory scale). Use of increasingly coarse milling conditions positively correlated with wort turbidity and reduced concentration of acetate and ethyl esters in new-make spirit. Similar to previous research within the brewing industry, turbid wort was generally associated with reduced ester content, particularly in samples produced under the coarsest milling conditions (mill gap: 1.5 mm). Turbidity of new-make spirit (diluted to 30% ABV) was reduced in samples produced from wort of elevated turbidity, likely due to reduced content of ethyl esters and other haze-active congeners.

Optimization of non-spherical particle flow in vertical waste heat recovery devices: Analyzing structural configurations

Vertical waste heat recovery devices are emerging but are immature. The vertical waste heat recovery devices of circular, square, and optimized designs were analyzed for a full capacity of 8 tons of sintered ore. Using DEM theory, the effects of particle size distribution, velocity, and wall forces on void fraction distribution and particle flow were examined. The circular device demonstrated superior mixed particle flow compared to the square device, achieving integrated flow for 50 % of particles in the cone, in contrast to 26 % for the square device. An optimized circular device achieved integral flow for 90 % of particles, significantly enhancing overall flow and reducing wall adhesion, attributed to its improved internal design. Through insert and distributor design, the overall particle flow within the device improved, with almost no particles remaining on the walls. These findings underscore the potential for enhanced heat recovery efficiency through optimized internal structures in waste heat recovery devices.

An experimental and theoretical study on effects of particle size distribution on flowability and film properties of organic powder coatings

An experimental and theoretical study on effects of particle size distribution on flowability and film properties of organic powder coatings

Interfacial performance evolution of ceramics-in-polymer composite electrolyte in solid-state lithium metal batteries

The incorporation of ceramics into polymers, forming solid composite electrolytes (SCEs) leads to enhanced electrical performance of all-solid-state lithium metal batteries. This is because the dispersed ceramics particles increase the ionic conductivity, while the polymer matrix leads to better contact performance between the electrolyte and the electrode. In this study, we present a model, based on Hybrid Elements Methods, for the time-dependent Li metal and SCE rough interface mechanics, taking into account for the oxide (ceramics) inclusions (using the Equivalent Inclusion method), and the viscoelasticity of the matrix. We study the effect of LLTO particle size, weight concentration, and spatial distribution on the interface mechanical and electrical response. Moreover, considering the viscoelastic spectrum of a real PEO matrix, under a given stack pressure, we investigate the evolution over time of the mechanical and electrical performance of the interface. The presented theoretical/numerical model might be pivotal in tailoring the development of advanced solid state batteries with superior performance; indeed, we found that conditions in the SCE mixture which optimize both the contact resistivity and the interface stability in time.

Particle size distribution effects on the light scattering properties in non-diluted colloidal suspensions: A numerical study

The static light scattering technique potentially offers a nondestructive evaluation of a particle size distribution in dense colloidal suspensions. Understanding the size distribution’s correlation with the light scattering properties and modeling electromagnetic scattering with high accuracy and efficiency are crucial for technique development. The polydisperse dependent scattering theory (DST) is an accurate model, but its calculation is costly. We aim to numerically examine the size distribution effects on the scattering properties of dense suspensions up to the volume fraction of 20% in the near-infrared wavelength of 600–1000 nm using three electromagnetic models: the polydisperse and monodisperse DST, and the local monodisperse approximation (LMA). We considered various size distributions in Gaussian and logarithmic forms with constant standard deviations of 21 nm and 101 nm in the mean diameter range of 75–700 nm by shifting the distribution while keeping its shape. We showed that the monodisperse approximation is invalid at a small mean diameter of less than 200 nm, even at the sharp Gaussian distribution. It suggests the strong size distribution effects. Meanwhile, the approximation holds at a large diameter of more than 650 nm, even at the broad logarithmic distribution. We showed that the LMA results nicely agree with the polydisperse DST results for all the current conditions. At the same time, the LMA calculations are over a thousand times faster than the polydisperse DST because the LMA reduces the sum calculation over particle diameter pairs. Thus, the LMA is a great candidate for the electromagnetic model.

Effect of particle size distribution on the dewatering circuit design; case study: iron ore tailing of the Gol-E-Gohar mining and industrial company

ABSTRACT Iron ore processing plants of the Gol-E-Gohar mining and industrial company have three thickeners. The thickeners’ underflow's is pumped to a tailings dam, with the solid content of about 50%. To increase water recovery, this research investigated the effect of the particle size distribution on the dewatering circuit design of tailings. Physical and chemical characteristics of the thickeners’ underflows (solid content, XRF, XRD, density, etc.) are determined and three different dewatering circuit designs considered. In the first design, only a pressure filter was considered for each stream separately, and in the second design, all streams were combined, and then particles coarser than 1 mm were removed using the screen and dewatered by a pressure filter. In addition, in the third design, all streams are combined and particles coarser than 250 microns are removed using hydrocyclone-screen. Particles smaller than 250 microns are dewatered using a pressure filter. The results showed that the required filtration area (m2) related to the dewatering circuits to reach 20% moisture of plants’ tailings are 1074, 926, and 912 m2, respectively. Finally, it is determined that because of the positive impact of coarse particles on the filtration performance and the operational problems related to the particles larger than 1 mm, all streams must be combined and dewatered using a pressure filter.