Particle Size Distribution Curves 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

A novel method for predicting coarse aggregate particle size distribution based on segment anything model and machine learning

Particle size distribution (PSD) is an important index property of granular materials. The conventional mechanical sieve analysis for PSD determination is labor-intensive, time-consuming, and inefficient. With the development of computer vision, image-based gradation prediction methods gradually emerge. However, previous studies mainly focused on images where individual aggregate particles are separated from each other without overlapping (i.e., not densely packed together), thus limiting their applicability. This study proposed a novel framework to predict the PSD of densely packed coarse aggregate particles, which is based on visual foundation model and machine learning with appropriate feature engineering. First, the segment anything model, which is one of the visual foundation models, was used for the instance segmentation of the densely packed aggregate particles. Then, the feature engineering was implemented with the segmentation result. The major quantitative indicators related to particle sizes were extracted from each mask, such as the area, the diameter of minimum enclosing circle, and the major axes of the equivalent ellipse of particle contours. Subsequently, the cumulative distribution curves of these indicators were plotted, followed by the data sampling operation on these curves to generate the feature vectors. The artificial neural network (ANN) model was then trained for gradation prediction with each of the feature vectors and the data points extracted from PSD curves used as the inputs and data labels, respectively. The model-training dataset consisted of 8160 different sets of digitally generated particle samples with known PSDs. Finally, verification test results of additional five different groups of digital particle samples and real coarse aggregate samples with known PSDs show that the root mean squared error (RMSE) of predicted aggregate sizes is 1.79 mm and 1.86 mm for digital and real aggregate particle samples, respectively. Therefore, the efficacy and feasibility of the proposed method was validated in terms of predicting the PSD of densely packed coarse aggregates from two-dimensional image information. As compared to the Mask RCNN combined with empirical formula of which the RMSE values were 5.12 mm and 5.84 mm for digital and real aggregate particle samples, respectively, the proposed framework demonstrates improved particle segmentation applicability and better PSD prediction accuracy.

Exploration of Fragmentation Mechanisms of Yellow Split Peas during Grinding Using a Multimodal Approach

In the context of food and agro-ecological transitions, the development of food applications based on legume flours and plant proteins requires a mastery of grain milling. While wheat grain milling has been extensively studied and is well-mastered, legume grinding and its underlying mechanisms are still poorly understood. The aim of this work is to contribute to the study of the fragmentation mechanisms of pea grains during grinding. Experiments were carried out on hulled yellow pea grains (Kameleon variety) ground under different conditions using a ball mill (MM400, Retsch®, Haan, Germany) or a micro-cylinder mill. The results showed that the grinding of pea grains, regardless of the type of mill, produced powders characterized by particle size distribution curves with a multimodal shape. The curve analysis was performed according to a simplified deconvolution approach, taking into account different particle populations without diameter overlap. Four particle populations of different sizes were identified and correlated with specific mechanisms governing the grinding of yellow split peas. The physical and biochemical properties of the resulting powders were determined. Taking into account the proportions of the four populations within the powders, the results showed a positive correlation between the volume proportions of very fine (0–10 µm) and fine (10–55 µm) particles within the powders and the starch damage rate and the specific surface area developed, irrespective of the type of mill.

Gas atomization of AA2017 aluminum alloy: Effect of process parameters in the physical properties of powders for additive manufacturing

Close-coupled gas atomization (CCGA) uses pressurized gas jets to atomize molten metals, producing powders suitable for additive manufacturing (AM). Optimization of processing parameters is crucial to achieve powders with good fluidity and high apparent density for laser powder bed fusion (L-PBF) and increase production yield. This study evaluated the influence of melt feed nozzle diameter, superheating temperature, and atomization pressure on AA2017 aluminum alloy powders' physical properties. Parameters variation poorly affected the median particle diameter (d50), while significantly altering the particle size distribution curves width (IDR = d90-d10). Suitable powders for AM/L-PBF were produced using a specific set of parameters (d0= 1.5 mm; ΔT= 150 °C; PG= 20 Bar), presenting appropriate fluidity and apparent density due to an optimal granulometric distribution and morphological characteristics. Mathematical analysis showed a good correlation between experimental and calculated mean particle size, suggesting an equation to predict percentile d90 based on previous correlations.

Water–ice phase transition in frozen soils: a mesoscopic numerical study based on lattice Boltzmann method

ABSTRACT The phenomenon of water–ice phase transition in frozen soils is the key to explaining the mechanism of frost heaving and thawing settlement disaster. However, numerical analysis of water–ice phase transitions in frozen soils at mesoscale is rarely reported. This study combines the modified Gibbs-Thomson equation and the enthalpy-based lattice Boltzmann model, and develops a mesoscale numerical method to simulate the water–ice phase transition in the local pores of saturated frozen soil during freezing and thawing process. In order to accurately simulate this process, a new η coefficient is proposed to modify the Gibbs-Thomson equation, which is unrelated to the type of soil sample and gradation characteristics. According to the particle size distribution curve, the two-dimensional random circle generation method is used to reconstruct the soil pore structure. The freezing and thawing processes are verified with the experimental data. A larger non-uniformity coefficient C u and curvature coefficient C c of the grain size distribution result in a lower degree of subcooling and lower residual water content of the soil during the freezing process. The new model provides an effective means to understand the water–ice phase transition in frozen soil at a mesoscopic scale.

Separation effect of Li+, Na+, and Mg2+ with alumina–lithium LDH doped with amorphous titanium dioxide

Alumina–lithium layered double hydroxide doped with amorphous titanium dioxide (TiO2@AlLi–LDH) was synthesized through the coprecipitation of Li+ and Al3+. The structural characteristics of TiO2@AlLi–LDH were analyzed via XRD, XPS, BET and DSC–TG. Titanium oxide anions could be inserted between layers in TiO2@AlLi–LDH, and TiO2@AlLi–LDH consists of nanoflake-sized particles. The average diameter of the particles is 231.0 nm, and the particle size distribution curve is close to the normal distribution curve. The BET surface area is 174.02 m2·g−1 after recrystallization. The Li+ adsorption process of TiO2@AlLi–LDH can be described by the pseudo–second–order model, and the adsorption capacity is 11.54 mg·g−1. The structure of TiO2@AlLi–LDH was destroyed because of the reaction between Mg2+ and CO32−. The presence of Na+ significantly reduces the Li+ adsorption ability of TiO2@AlLi–LDH without destroying the structure. The separation coefficient of Mg2+/Li+ is 4269.76 when the initial mass ratio of Mg2+/Li+ is 350.20, and the separation coefficient of Na+/Li+ is 226.20 when the initial mass ratio of Na+/Li+ is 329.40. The Li+ adsorption amount of TiO2@AlLi–LDH in Qarhan salt lake brine is 5.66 mg·g−1, suggesting potential for industrial application.

Crushing characteristics and particle size distribution of steelmaking slag according to repetitive compaction loads

Steelmaking slag, which is used as a construction material, can be crushed during compaction or repetitive loading in construction work. This crushing has a considerable influence on its physical and mechanical properties. Therefore, this study aims to evaluate/estimate the crushing properties and particle size distribution of steelmaking slag under various compaction loads. Accordingly, compaction tests were conducted by subjecting steelmaking slag with 10 different particle sizes to an increasing number of compaction cycles (1–15 times) to simulate repetitive compaction loading. The compaction test results were analyzed by considering the particle size distribution, particle size distribution curve, breakage factors, and fractal dimension. The results revealed that these factors could be influenced by changing the voids in steelmaking slag by altering the repetitive compaction load and particle size. An equation for predicting the particle size distribution from the compaction energy and particle size based on the sequence limit with the rational and the recurrence formulas was proposed. The proposed equation demonstrated excellent accuracy, and it can be utilized in efficiently predicting the particle size distribution curve.

Ecofriendly cascade extraction of antioxidants from Origanum vulgare: Morphological and rheological behavior of microparticles formulations

Bioactive compounds from Origanum vulgare have been extracted to enriched foods. This has contributed to consumer acceptance. These extracts have been obtained using a sequential extraction process to recover the maximum amount of the bioactive compounds for the formulation of microparticles. Extracts obtained from both extraction technologies (ultrasound and pressurized hot water extraction) were analyzed. When the ultrasound technology was used, total phenolic content and protein content were highest (29 % and 4.7 %, respectively). The second extraction showed lower values around 72 % for TEAC value, 14 % phenolic content and 5.4 % protein content (g/100 extract). The IC50 for the ultrasound extract is 0.27 g/L and the lower value for the sequential treatment is 0.49 g/L. The polymeric microparticles were formulated with the ultrasound extract at different percentages of mannitol (2 % and 5 %). It was observed that microparticles (5 % mannitol) had a smaller particle size distribution (∼12 µm) and flow curves exhibiting shear-thinning behavior, which were successfully fitted with the power law model.

Important roles of coarse particles in pasting and gelling performance of different pulse flours under high-temperature heating

Dehulled pea, lentil, and faba bean grains were milled into flours with 0.5- to 2.5-mm sieves. As the particle size decreased, damaged-starch contents of the flours from the same pulse crop increased. At a holding temperature of 95 °C in RVA, peak and final viscosities and gelling ability of the flours generally increased as the particle size decreased. When the holding temperature increased from 95 to 140 °C, pasting viscosities of pea and lentil flours and gel hardness of lentil flours gradually decreased. In contrast, pasting viscosities and gel hardness of faba bean flours reached the highest values at 120 °C. The comparison of the pulse flours varying in particle size across the three market classes revealed that coarse particles comprising agglomerated starch, protein, and dietary fiber (i.e., particles of the second peak in the bimodal particle-size distribution curves) showed significant correlations with certain important functional properties of pulse flours.

Identification of the complete particle size distribution of landslide debris by the combined method of scaled image analysis, line-grid analysis and laboratory sieve analysis

BackgroundGround failures in a slope due to gravity, are commonly known as landslides. Depend on the compositional, geological, and structural characteristics of the unstable initiation zone and the erosional composition of the propagation zone decide the complete particle size distribution of the moving mass and its gradation. This information is most important for the study of downslope movement. Only laboratory sieve analysis cannot fulfil this target because the natural debris contains a wide range of particle sizes, especially boulders. The combined method of scaled image analysis and laboratory sieve analysis or the combined method of line-grid analysis and laboratory sieve analysis was proposed to fulfil the requirement. To study the proposed combined methods, five different locations within the downslope propagation zone from the Aranayake landslide in Sri Lanka were surveyed and analyzed. In image analysis, the high-resolution scaled image of deposited debris was analyzed by computer-based image analysis for particle sizes. Small particles were addressed by the laboratory sieve analysis using the representative debris sample taken from the same location. If the boulder sizes within the debris are too big to address this method, then the Line-grid method was performed. The particles in every 0.5 m along a measured line of debris deposition were measured in this method. If the selected location contains small particles that cannot measured manually, the representative sample was used for the laboratory sieve analysis to fulfil this range.ResultsThe results of three locations indicated a 40% distribution of < 10 mm and a 60% distribution of > 10 mm representing the general distribution of the debris. Two distributions deviated from the general distribution that was surveyed and analyzed from special locations of the “near boundary of flow path” and “slope change zone” of the landslide.ConclusionsThe combined methodology yielded successful results of complete particle size distribution for the wide range of particle sizes in debris. The variation of the particle size distribution curves of debris along the downslope depositions is planned to be used for the study of downslope propagation, damage zone assessment studies, and predicting the representative composition of future failures.

Numerical analysis of dump slope stability using material properties obtained by parallel gradation method

The stability of the dump slope depends on many parameters, mainly the shear strength of the dump material. Obtaining strength parameters of dump material is vital in dump stability analysis. Dump material consisting of particles of varying sizes, as large as 1000 mm, is typical. It is challenging to obtain the material strength properties of such large particles in the laboratory. Extrapolation of the material strength properties of the modelled samples prepared by parallel gradation technique is used to calculate the dump material strength properties in this study. A closer agreement is found between the predicted and calculated values of the angle of internal friction. Numerical modelling has been carried out with the obtained material properties using RS2 V9.0, a finite element package, to analyse the stability of a dump slope. It is observed from the results that FOS (factor of safety) increase with an increase in dmax (maximum particle size), keeping the shape of the PSD (particle size distribution) curve constant. The paper develops a slope stability analysis methodology considering particle size's effect on slope stability. The proposed method can be used for accuracy and reliable results for slope stability analysis.

Fractal simulation of hydrophobic flocculation fragmentation and reconstruction of coal particles

Based on a diffusion limited cluster aggregation model, this study analyzed the fragmentation and reconstruction of flocs during the hydrophobic flocculation process of coal particles. The flocs gyration radius and gyration fractal dimension calculated by the program characterize the geometric size and spatial structure of the coal particle flocs, respectively. With advancing step length, the distributions of gyration radius first increased and then decreased and finally basically stabilized at approximately 1.70 ± 0.2, indicating that the reconstruction of flocs is reversible in geometric size. However, the gyration fractal dimensions first decreased and then increased and finally stabilized at 1.49, 1.63, 1.60 and 1.51 with increasing step length, showing variability. This indicated that the spatial structure of the flocs is irreversible. The above conclusions of the simulation analysis were confirmed by the floc particle size distribution curves and the image analysis of surface fractal dimensions. The study clarifies the morphological changes and fragmentation-reconstruction changes of flocs and improves the hydrophobic flocculation mechanism of coal particles.

Preparation and properties of the fine ground strontium-based endodontic cements.

In this study, fine powders of tristrontium aluminate (S3A) and distrontium cerate (S2Ce) cement were prepared using a dry grinding process, and their mechanical and ion dissolution properties were estimated. Fine cements showed the particles about 10 μm in diameter or smaller with sharp particle size distribution curves. The setting reaction of the fine cements was rapid; therefore, a 0.1% w/v of citric acid solution was used as the retarder. The compressive strengths of the fine cements were improved compared to those of the coarse cements at both 1 and 28 days after mixing at a water/powder ratio (W/P) of 0.4. The dissolution of Sr and Al ions from fine S3A cement was enhanced. However, the relative flowability decreases with fine grinding. Further studies on flowability, handling property are required. Additionally, the biological effects of endodontic cement should be studied both in vitro and in vivo.

Characterization of particle size segregation and heterogeneity along the slopes of a waste rock pile using image analysis

Large amounts of waste rock are produced during mining operations and often disposed of in large piles. Particle size segregation usually occurs during waste rock disposal, which can lead to high variations of particle size distribution (PSD) along the pile slope, increasing the risk for hydrogeotechnical instabilities. Determining segregation in situ is, therefore, critical to implement control measures and optimize deposition plans. However, characterizing PSD at field scale remains challenging because of the large dimensions of the pile, the instability of the blocks and the steep slopes. In this study, images, covering a 1400 m wide and 10 m high section of a waste rock pile, were taken and analyzed using image analysis to characterize segregation along the slope of the pile. PSD curves in different sections along the slope were determined and the segregation degree and characteristic diameters (e.g., D10, D50, D80,D95) were quantitatively compared. Results allowed to quantify segregation along the vertical direction of the pile, showing that segregation degree increased from − 0.77 ± 0.39 in the top (finer zone) to + 0.4 ± 0.14 in the bottom (coarser zone). Significant lateral heterogeneity was also observed with maximum diameters varying between 80 and 180 cm in the bottom section. Such segregation and lateral heterogeneity could induce significant variations of waste rock properties, with, for example, hydraulic conductivities varying by more than 2 orders of magnitude within the pile.

Enhanced soy sauce stability and reduced precipitation by improving critical steps in the fermentation process

Conventional high-salt dilute-state soy sauce is vulnerable to precipitation after processing, which will reduce the systemic stability and nutrition of soy sauce. This work aims to optimize key steps of the soy sauce fermentation process to improve its stability and reduce precipitation. The amino acid nitrogen (AAN) and the total nitrogen (TN) contents of the new soy sauce were 8.3 g/L and 18.7 g/L, which were significantly enhanced by 33.9% and 14.0%, respectively, compared to the control group. More flavor substances were detected in the new soy sauce, including furans and pyrazines, which contribute to the special flavor of soy sauce. The particle size distribution curve was significantly shifted to the left, and the absolute value of zeta-potential increased. The new fermentation process soy sauce had a higher raw material utilization rate, smaller average particle size of 15.56 μm, and significantly higher stability when combined with the rheological examination. Consequently, the quality and flavor of soy sauce can be improved by using the new fermentation process.

A refined representation method of the particle size distribution curve based on grading entropy

The particle size distribution (PSD) curve is an important expression of the basic properties of the soil. The characteristic parameters such as median particle size D50, effective particle size D10, and some combinations of characteristic parameters can only represent some points of the PSD curve, failing to represent all information of the PSD curve. In this paper, a fraction characteristic parameter F that could reflect the fraction size variation of the PSD curve was introduced based on grading entropy. And a new presentation method of the A-B-F three parameters was proposed for a refined representation of the PSD curve. It was found that the newly constructed model not only better represents the differences in the width of PSD curves but also has a higher sensitivity than the A-B two-parameter model proposed by Lőrincz. For PSD curves with similar distributions, the new presentation method has a higher degree of discrimination than that of the D50-Cu-Cc three-parameter or the four-parameter combination Gc proposed by Arshad. Finally, the application of this new method in describing the spatial nonuniformity distribution of depositions and predicting the soil hydraulic conductivity was discussed. The research results can provide a reference for the refined representation of PSD curves.

Green synthesis of reduced graphene oxide anchored Fe3O4‐Pd hetero‐nanostructure: An efficient, magnetically separable and reusable catalyst for Beckmann rearrangement of aldoximes to amides

The multifaceted Fe3O4‐Pd@rGO nanocomposite (NC) has been synthesized successfully by a biogenic method using Ocimum tenuiflorum leaf extract. The preparation of graphene oxide (GO) was done by the well‐known modified Hummer method. The as‐synthesized Fe3O4‐Pd@rGO NC was extensively characterized by various analytical techniques, namely, Fourier transform infrared (FTIR), X‐ray diffraction (XRD), field emission scanning electron microscopy‐energy‐dispersive X‐ray spectroscopy (FESEM‐EDX), high‐resolution transmission electron microscopy (HRTEM), inductively coupled plasma‐atomic emission spectrometry (ICP‐AES), X‐ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM) and Brunauer–Emmett–Teller (BET) surface area analysis. The absence of peak corresponding to υ(CO) at 1732 cm−1 in the FTIR spectrum of Fe3O4‐Pd@rGO enumerates the reduction of GO to reduced graphene oxide (rGO) during Fe3O4‐Pd nanoparticle (NP) synthesis with O. tenuiflorum leaf extract. The XRD pattern reveals the existence of rGO, cubic‐phased spinel‐structured Fe3O4 along with the formation of metallic Pd NP without any impurities. The FESEM image designates the spherical and flake‐like morphology of the NC. The crystallite size of the NC was calculated employing the Debye–Scherrer equation and was found to be 3.45 nm corresponding to the (220) plane. The average particle size of Fe3O4‐Pd NPs as estimated from the particle size distribution curve was ascertained as 3.03 nm. The utmost saturation magnetization value of the NC as evaluated by VSM study has appeared at 0.6219 emu g−1 having coercivity value of 335.1 Oe and remanent magnetization value of 0.0767 emu g−1, suggesting the existence of a ferromagnetic material in the synthesized NC. It was a stable and highly efficient catalyst for Beckmann rearrangement of aldoximes using in an environment‐friendly medium. It afforded up to 99% isolated yield of the preferred products under acid‐free condition, avoiding the use of any harsh chemicals that will be beneficial for future industrial applications. Finally, the magnetic component of the NC allowed for easy recovery of the catalyst, thereby eliminating the chance of leaching of metal atoms, and was reusable till six successive cycles without apparent loss of its catalytic performance.

Use of Particle Size Distribution Model to Produce High-Flowability Cementitious Composites

High packing density is desired for production of high-flowability cementitious composites. To achieve dense packing, various particle size distribution models have been proposed by researchers. In present study, with the use of two supplementary cementitious materials at different scale smaller than ordinary Portland cement (OPC), an ideal particle size distribution curve according to modified Andreasen’s formula has been produced. Analysis of particle size distribution showed that blending the cement with superfine cement (SFC) and/or condensed silica fume (CSF) would make the curve closer to the ideal curve, hinting that a better packing could be achieved. Packing densities of the cementitious materials were then directly obtained through a wet packing method, and results verified that cementitious materials mix blended with SFC and/or CSF own higher packing densities.

Experimental Investigation on Particle Breakage Behavior of Marine Silica Sand under High-Stress Triaxial Shear

There is often obvious particle breakage for silica sand under high-stress, which will lead to the bearing capacity reduction and excessive settlement of the foundation. This paper focuses on the particle breakage characteristics of marine silica sand from the East China Sea under high-stress conditions. A series of conventional triaxial tests for silica sand, including consolidated drained (CD) and consolidated undrained (CU) shear tests, were conducted under the confining pressures in the range of 2–8 MPa to investigate the breakage rule during the shearing process. The developments of particle breakage index Br with axial strain ε1 and volumetric strain εv present hyperbolic and linear trends, respectively. A hyperbolic model was adopted to describe the relationship of Br and ε1 and the corresponding model parameters were obtained. The particle breakage index also has a good correlation with the input work per unit volume under various average stresses, regardless of the stress history. Furthermore, the relationship between the fractal dimension and the particle breakage was studied based on the particle size distribution curve. It is concluded that the fractal dimension increases in an up–convex hyperbolic trend with the increase of particle breakage index. The dividing radius for whether the silica sand particles exhibit the fractal features is determined as approximately 0.4 mm. This is anticipated to provide reference and supplementary test data for analyzing sand constitutive models/environments regarding particle crushing.

Insights of keratin geometry from agro-industrial wastes: A comparative computational and experimental assessment.

Understanding the structural properties of keratin is of great importance to managing their potential application in keratin-inspired biomaterials and its management of wastes. In this work, the molecular structure of chicken feather keratin 1 was characterized by AlphaFold2 and quantum chemistry calculation. The predicted IR spectrum of the N-terminal region of feather keratin 1, consisting of 28 amino acid residues, was used to assign the Raman frequencies of the extracted keratin. The MW of experimental samples were 6 & 1kDa while the predicted MW (∼10kDa) of β-keratin. Experimental analysis shows the magnetic field treatment could affect the functional and surface structural properties of keratin. The particle size distribution curve illustrates the dispersion of particle size concentration, while TEM analysis demonstrates the reduction of particle diameter to 23.71±1.1nm following treatment. High-resolution XPS analysis confirmed the displacement of molecular elements from their orbital.