Analysis Of Particle Distribution Research Articles

Determination of representative elementary volume of fault core materials by particle distribution analysis

Fault core materials (fault breccia and fault gouge) exhibit heterogeneous particle size distributions due to many factors, including the type of cataclasis, the degree of weathering, and the scale and mechanism of the fault system. When studying particle size distributions in fault core materials, there is no clear standard of the sample size that should typically be used for testing and analysis. In this study, we present a method to establish the ideal sample size by statistically assessing a suite of laboratory tests on 451 fault-core samples from 21 locations in South Korea. These samples were divided into five different classes according to grain size. Weight ratios of gravel, sand, and silt/clay were calculated from laboratory tests on each sample, and the means and standard deviations were subsequently assessed via analysis of variance and multiple comparison analysis. The results of the analysis of variance suggested that classes 1–5 are different from each other in at least one factor. Tukey’s HSD tests and Duncan’s LSR tests were also applied to identify groups within the classes that might be statistically similar to each other. In this manner, it was found that classes 1 and 2 could be grouped together (group A), as could classes 3, 4, and 5 (group B). Standard deviation means and distribution ranges within groups were used to deduce that group B, rather than group A, contained the sample sizes that best represented the site. Furthermore, class 3 (which had the smallest weight among the different classes in group B) was determined as being the representative elementary volume (REV). This deduction is consistent with the recommendation for reference sample size used in soil particle size analysis (as defined by the American Society for Testing and Materials).

Solid state characterization of two novel gums from Cedrela odorata and Enterolobium cyclocarpum

Functional and physicochemical properties of two novel polymers from plants were characterized with a view of determining suitability for use in pharmaceutical dosage forms. Cedrela gum (CD) and Enterolobium gum (ET) were extracted from the incised trunk of Cedrela odorata (Meliaceae) and Enterolobium cyclocarpum (Mimosoideae) trees respectively. The gums were characterized using particle size and distribution analysis, density measurements, swelling index, angle of repose, Carrs’ compressibility index and Hausner’s ratio. Other physicochemical properties were determined by pH measurement, powder X-ray diffractometry (PXRD), scanning electron microscopy (SEM) differential scanning calorimetry (DSC) and viscometry. Hydroxypropylmethyl cellulose (HPMC) was the reference polymer. The polymers generally had particle size range of 145–436 µm and the particles were normally distributed. The gums had comparable particle density, Carr’s index and Hausner’s ratio with HPMC, indicating similar packing properties between the gums and HPMC. All polymers had angle of repose values in the range for excellent flow properties. The polymers were of alkaline pH, thereby suggesting compatibility with basic drugs. Hydration capacity of the polymers was generally high. The ranking order for viscosity was ET > CD > HPMC (p < 0.05). Similar thermal behaviour was recorded by DSC for the gums and HPMC. SEM revealed irregularly shaped and aggregating surface morphology while broad halo diffraction patterns were obtained by the PXRD. CD and ET gums showed comparable functional and physicochemical properties with HPMC, a standard polymer. These gums could be used as pharmaceutical excipients in bioadhesive formulations and other drug delivery systems.

Is autocorrelation image analysis the proper method in nanoparticle sizing?

Nanomaterials display a range of properties which are completely different to those of bulk materials. This unexpected behaviour is particularly apparent when the size of objects reaches the nanometre scale. A wide range of methods are currently used to characterize the properties of nanoparticles. The aim of this work is to analyse the application of image autocorrelation of atomic force microscope samples in determining the distribution of nanoparticle sizes. We propose a model of cross-correlation, which expands upon a recently published model and which further allows us to determine the limits of the image autocorrelation method. Numerical simulations of different configurations of positions, sizes and shapes of particles were used to study the impact of these parameters on the computation of particle size distribution. The precision of the method was found to be strongly dependent on the shape of particles and thus approximate corrections of the model autocorrelation function are limited in terms of validity. Furthermore, the omission of the cross-correlation component during analysis of very dense particle distributions causes a deformation of the central part of the autocorrelation function and a significant increase in errors. Taking the basic principles of auto correlation into consideration, it is clear that this method is very sensitive to any disturbance of the topographic surface of the distribution. Therefore, we suggest that data obtained using image autocorrelation particle distribution analysis should be interpreted very carefully and that the limits presented in this paper should be taken into consideration in such an interpretation.

Analysis of Particle Distribution in Milled Al-Based Composites Reinforced by B4C Nanoparticles

In the present work, high-energy ball milling was employed to synthesize Al-(5-10 wt.%)B4C nanocomposite. To do this, two sizes of particles of 50 nm as nanoparticles (NPs) and 50 μm as coarse particles (CPs) were used. The morphology and microstructure of the milled powders were characterized using particle size analyzer, SEM, TEM and EDX techniques. It was found that milling time, B4C particles size and their content strongly affect the characteristics of powders during milling process. The breaking and cold welding of powders was recognized as two main competitive actions during the milling process that influence the microstructural evolutions. It was found that the presence of CPs led to the formation of microcracks which promote the fracture process of Al powders. The dominated mechanisms during the fabrication of composites and nanocomposites were discussed. Also, the theoretical issues regarding the changes in morphology and distribution of B4C particles in CPs and NPs are clarified.

Multifractal analysis of charged particle distributions using horizontal visibility graph and sandbox algorithm

Horizontal visibility graphs (HVGs) and the sandbox (SB) algorithm usually applied for multifractal characterization of complex network systems that are converted from time series measurements, are used to characterize the fluctuations in pseudorapidity densities of singly charged particles produced in high-energy nucleus–nucleus collisions. Besides obtaining the degree distribution associated with event-wise pseudorapidity distributions, the common set of observables, typical of any multifractality measurement, are studied in [Formula: see text]O-Ag/Br and [Formula: see text]S-Ag/Br interactions, each at an incident laboratory energy of 200 GeV/nucleon. For a better understanding, we systematically compare the experiment with a Monte Carlo model simulation based on the Ultra-relativistic Quantum Molecular Dynamics (UrQMD). Our results suggest that the HVG-SB technique is an efficient tool that can characterize multifractality in multiparticle emission data, and in some cases, it is even superior to other methods more commonly used in this regard.

Quantitative distribution analysis of alumina inclusion particles in ferritic stainless steels by using laser‐induced breakdown optical emission spectrometry

This paper describes an analytical method for determining the spatial distribution of alumina inclusion particles in several ferritic stainless steels by laser‐induced breakdown optical emission spectrometry with a single‐shot laser scanned on the sample surface. For this purpose, an irradiation system, which comprised a Q‐switched Nd:YAG laser with an average energy of 50 mJ/pulse and a precisely driven X‐Y‐Z sample stage, was prepared. A Czerny–Turner‐mounting spectrograph equipped with an ICCD detector was employed for a time‐resolved measurement of the laser‐induced breakdown optical emission spectrometry signal. The intensity ratio of Al I 396.152 nm to Cr I 396.368 nm was measured each for the single shot, while the irradiation positions were step‐wise moved in the X‐Y direction and then the same sampling area was repeatedly irradiated by subsequent laser shots in the Z direction. The number of alumina particles was mapped from the intensity ratio of Al/Cr each for the irradiation points in both the lateral and in‐depth directions, enabling the distribution of alumina particles to be presented. The resolution of our measuring system was 40 μm in the lateral position and 6–7 μm in the depth direction, which were mainly determined by the crater size of a laser shot. A typical size of the alumina particles (several μm) was smaller than their resolutions; nevertheless, the suggested method would be still more effective to give the distribution of alumina particles, especially the coarse ones, because of its rapid response for the analytical result. Copyright © 2017 John Wiley &amp; Sons, Ltd.

Size distribution analysis of airborne wear particles released by subway brake system

Contributions of exhaust and non-exhaust sources to traffic-related particulate matter (PM) pollution in the atmosphere are almost identical and the most important non-exhaust source is known to be brake wear particles. In order to understand the properties and harmful effects of wear particles on people, accurate information on size distribution of brake wear particles is needed. Our previous study investigated the measured changes in size distribution of nanoparticles of 500nm or smaller to understand the origin of nanoparticles due to temperature increases on the friction surface. The present study was intended to investigate the characteristics of size distribution (5.6nm–32μm) of PM released under different braking conditions by using different instruments. The measurement results under 9 braking conditions using 3 different instruments showed that the size distribution characteristics of particles can be divided into two main types according to braking energy. The first type is of PM up to 10 μm in size and with a peak number concentration at 0.2–0.75μm regardless of braking energy, while the second type is of PM around 10nm in size generated only when braking energy increased and particles that increased up to 100nm. In addition, we found that the size distributions measured by the optical particle counter (OPC) and the aerodynamic particle sizer (APS) were consistent by assuming a mean diameter ratio of two instruments.

Numerical study of particle mixing in a lab-scale screw mixer using the discrete element method

This study employs the discrete element method (DEM) to simulate particulate flow and investigate mixing performance of a lab-scale double screw mixer. The simulation employs polydispersed biomass and glass bead particles based on experiments conducted in previous studies. Visual examination of particle distribution and statistical analysis of particle residence times of experimental data served as model validation. Statistical analysis indicates a maximum 9.8% difference between the experimental and simulated biomass particle mean residence time, and visual observations suggest the simulation captures the particle mixing trends observed in the experiments. Results indicate that the particle mean mixing time, non-dimensionalized by ideal flow time in the plug flow reactor, varies between 1.008 and 1.172, and it approaches 1 with increasing biomass feed rate. The mixing index profile in the axial direction shows a mixing-demixing-mixing oscillation pattern. Increasing screw pitch length is detrimental to mixing performance; decreasing the solid particle feed rate reduces the mixing degree; and increasing the biomass to glass bead size ratio decreases mixing performance. A comparison of a binary, single-sized biomass and glass particles mixture to a multicomponent mixture indicates that the binary system has similar mixing pattern as a multicomponent system. These findings demonstrate that DEM is a valuable tool for the design and simulation of double screw mixing systems.

Graded epoxy-hard coal composites: Analysis of filler particle distribution in the epoxy matrix

The aim of the work was to achieve assumed gradation of hard coal particles distribution in epoxy matrix and thus gradation of properties. It was done by proper selection of compounds composition and conditions of the gradation formation. The graded composites were produced using centrifugal casting. Two types of epoxy resins as a matrix and two types of hard coal of various granulation as a filler were used. Samples in the form of bushings with radial carbon filler gradation were produced by changing filler type, its volumetric content and parameters of centrifugal casting. The first part of the paper presents results of graded materials structure investigations. The microscopic observations of the structure of composites prepared according to elaborated experimental program show that the composites are characterized by continuous change of the filler particles content in radial direction, so they can be classified as graded materials. Results also show that gradation of particles content and thus gradation of properties may be planned and foreseen when mechanisms of gradation formation are known.

Influence of microwave irradiation on boron concentrate activation with an emphasis on surface properties

In this study, we employed microwave irradiation for activating boron concentrate, an abundant but low-grade boron mineral resource in China. The boron concentrate was pretreated by microwave irradiation based on TG-DTG-DSC analysis, and the influence of each parameter on processing efficiency was characterized using chemical analysis, XRD, SEM, FTIR and particle distribution analysis. Subsequently, the surface properties of boron concentrate and the mechanism of microwave irradiation was analyzed. Our results indicate that microwave irradiation decreased the processing temperature and shortened the roasting time by accelerating dehydroxylation and oxidation reactions in the boron concentrate, reducing the particle diameter and damaging the microstructure of the minerals, and it increased the B2O3 activity of boron from 64.68% to 86.73%, greater than the optimal conventional treatment. Compared with the simple thermal field, microwave roasting obviously increased ability of the boron concentrate to absorb OH− in the leachant and promoted boron leaching by expanding the contact area of the mineral exposed to leachant, boosting the amount of Mg2+ and Fe3+ on mineral surfaces, and increasing the hydrophilicity of the boron concentrate respectively. It enhanced the γSVLW and γSV− of boron concentrate from 29.15mJ/m2 and 5.07mJ/m2 to 37.07mJ/m2 and 12.41mJ/m2.

LA-ICP-MS Allows Quantitative Microscopy of Europium-Doped Iron Oxide Nanoparticles and is a Possible Alternative to Ambiguous Prussian Blue Iron Staining.

The development of iron oxide nanoparticles for biomedical applications requires accurate histological evaluation. Prussian blue iron staining is widely used but may be unspecific when tissues contain substantial endogenous iron. Here we tested whether microscopy by laser ablation coupled to inductively coupled plasma mass spectrometry (LA-ICP-MS) is sensitive enough to analyze accumulation of very small iron oxide particles (VSOP) doped with europium in tissue sections. For synthesis of VSOP, a fraction of Fe3+ (5 wt%) was replaced by Eu3+, resulting in particles with 0.66 mol% europium relative to iron (Eu-VSOP) but with otherwise similar properties as VSOP. Eu-VSOP or VSOP was intravenously injected into ApoE-/- mice on Western cholesterol diet and accumulated in atherosclerotic plaques of these animals. Prussian blue staining was positive for ApoE-/- mice with particle injection but also for controls. LA-ICP-MS microscopy resulted in sensitive and specific detection of the europium of Eu-VSOP in liver and atherosclerotic plaques. Furthermore, calibration with Eu-VSOP allowed calculation of iron and particle concentrations in tissue sections. The combination of europium-doped iron oxide particles and LA-ICP-MS microscopy provides a new tool for specific and quantitative analysis of particle distribution at the tissue level and allows correlation with other elements such as endogenous iron.

Size Reduction Characteristics of Yellow Poplar in a Laboratory Knife Mill

ABSTRACT Size reduction is one of the major pre-processing operations in using biomass as a source of energy or rawmaterials for forest products industry. The grinding characteristics of dried yellow poplar wood chips wereinvestigated using laboratory knife mill with three different screen aperture diameters to provide the basicinformation for the optimizing of size reduction processes in biomass industry. Average specific energy con-sumptions were 0.157, 0.137, and 0.093 Wh/g for the screen aperture diameters of 5.0, 7.5, and 9.0 mm, respectively. According to the results of size distribution analysis of ground particles, the sizes of the most of ground particles were much smaller than the aperture diameters of the screens installed on knife mill used in this study. Keywords : size reduction, biomass, knife mill, specific energy consumption for milling, particle size distribution, Liriodendron tulipifera L. 1 Date Received November 19, 2015, Date Accepted December 28, 2015 2 College of Agriculture and Life Science, Chonnam National University, Gwangju 61186, Republic of Korea

Effects of precursor particle size on the performance of LiNi0.5Co0.2Mn0.3O2 cathode material

Ni0.5Co0.2Mn0.3(OH)2 precursors with different particle sizes and Li2CO3 were used as the raw materials to synthesis layered structure LiNi0.5Co0.2Mn0.3O2 material in this paper. XRD Rietveld refinement, BET specific surface area (SSA) analysis, particle distribution analysis and other electrochemical tests were performed to determine the effects of particle size on the performance of LiNi0.5Co0.2Mn0.3O2 material. Physical and electrochemical characterizations demonstrate that sample NCM523-D3 (3μm) has the best layered structure, and with the decrease in precursor particle size, the cation mixing degree shows up a decrease trend while the specific surface area increases from 0.236m2g−1 to 0.937m2g−1. Sample NCM523-D3 presents a better rate capability than NCM523-D6 and -D9, whose average capacity for 1C, 2C, 5C and 10C reaches 155.7, 145.1, 128.2 and 97.5mAhg−1, respectively. Although the CV and EIS tests show that NCM523-D3 has the maximal impedance among all samples, but the bigger crystallite dimension and larger SSA of NCM523-D3 are the key factors affecting the outstanding capacity and rate performance of the material.

Extrudate Characteristics Produced from High Density Screw-Type Extruder Machine

Etrudate characteristics of briquettes produced and effects of extrusion factors using an existing screw extruder have been investigated. The feedstock material used in the test is sawdust collected from sawmills around Ibadan metropolis. Particle distribution analysis of materials collected showed that the size varies between 6-8 mm with 10-20% powdery component (&lt; 4 mesh) which is known to give better products. Samples of briquettes produced were used for physical characterization. Physical characteristic studies on samples indicate briquette length (&gt;300mm), dimensionally stable with no significant change in dimension during and after production. Performance tests carried out on machine revealed three (3) critical factors that significantly affect extrusion process; 1) Pre-densification within the extruder barrel results in high pressure requirement to push material through the die ring 2) Due to high pressure requirements as a result of early densification, there is a loss of power along power transmission line 3) Short material dwell time within the die results in weak products. Notable conditions of briquette during extrusion include; 1) extrudate surface cracks, 2) shooting (sudden explosion within the extruder barrel) leading to forceful ejection of materials from the machine and 3) extrudate bowing (warping) attributable to 1) non uniform extrudate thickness, 2) surface quality of the inner race of die ring, 3) loose inter-particle networking and binding properties of material– a condition not favourable to briquette formation, 4) localized heating within the extruder as a result of moisture differentials.

Extrudate Characteristics Produced from High Density Screw-Type Extruder Machine

Etrudate characteristics of briquettes produced and effects of extrusion factors using an existing screw extruder have been investigated. The feedstock material used in the test is sawdust collected from sawmills around Ibadan metropolis. Particle distribution analysis of materials collected showed that the size varies between 6-8 mm with 10-20% powdery component (&lt; 4 mesh) which is known to give better products. Samples of briquettes produced were used for physical characterization. Physical characteristic studies on samples indicate briquette length (&gt;300mm), dimensionally stable with no significant change in dimension during and after production. Performance tests carried out on machine revealed three (3) critical factors that significantly affect extrusion process; 1) Pre-densification within the extruder barrel results in high pressure requirement to push material through the die ring 2) Due to high pressure requirements as a result of early densification, there is a loss of power along power transmission line 3) Short material dwell time within the die results in weak products. Notable conditions of briquette during extrusion include; 1) extrudate surface cracks, 2) shooting (sudden explosion within the extruder barrel) leading to forceful ejection of materials from the machine and 3) extrudate bowing (warping) attributable to 1) non uniform extrudate thickness, 2) surface quality of the inner race of die ring, 3) loose inter-particle networking and binding properties of material– a condition not favourable to briquette formation, 4) localized heating within the extruder as a result of moisture differentials.

나노입자 합성방법에 따른 타이타늄산바륨 나노입자뭉침 현상 연구

타이타늄산바륨(<TEX>$BaTiO_3$</TEX>)은 대표적인 강유전 물질로 유전상수가 200 이상의 값을 나타내는 물질이다. 타이타늄산바륨을 나노입자화하면 나노커패시터(nanocapacitors)와 강유전체 메모리(ferroelectric random access memories)와 같이 여러 용도로 응용 가능하다. 하지만, 나노입자의 합성방법에 따라 나노입자의 분산특성이 달라지며 이에 활용할 수 있는 분야가 달라질 수 있다. 본 연구에서는 타이타늄산바륨 나노입자를 옥살레이트법(oxalate method)과 sol-gel법(ambient condition sol method)으로 합성하고 각 방법에 따른 나노입자의 크기와 분산상태를 확인하였다. 각각의 공정에 사용한 캡핑 에이전트(capping agent)는 poly vinyl pyrrolidone (PVP)을 옥살레이트법에 이용하였고 sol-gel법에는 tetrabutylammonium hydroxide (TBAH)를 이용하였다. 합성된 나노입자의 X-선 회절 분석 패턴을 분석하여 cubic 결정구조를 갖는 타이타늄산바륨을 확인하였다. 푸리에(Fourier) 변환 적외선 분광분석을 이용하여 나노입자의 캡핑 에이전트 결합상태와 시차주사현미경과 입도분석기를 이용한 나노입자의 크기 및 뭉침 변화를 확인하였다. <TEX>$BaTiO_3$</TEX> is typical ferromagnetic materials with dielectric constant of above 200. <TEX>$BaTiO_3$</TEX> nanoparticles applications are available for multiple purposes such as nanocapacitors, ferroelectric random access memories, and so on. Applications are is diverse from the dispersion of nanoparticles depending on the route of synthesis. In this study, <TEX>$BaTiO_3$</TEX> nanoparticles were synthesized by two different methods such as oxalate method and sol-gel process (ambient condition sol method). Particle size and dispersion condition were studied according to the preparation method and capping agent. Poly vinyl pyrrolidone (PVP) was used as a capping agent in oxalate method and tetrabutylammonium hydroxide (TBAH) used as a capping agent in sol-gel process each. Cubic crystal structure of <TEX>$BaTiO_3$</TEX> phase could be confirmed by X-ray diffraction analysis. Fourier transform-infrared spectroscopy was employed for the confirmation of the capping agent and <TEX>$BaTiO_3$</TEX> nanoparticles. The particle size and distribution analysis was also performed by particles size analyzer and scanning electron microscope.

Structural, morphological and electrochemical investigation of LiNi0.6Co0.2Mn0.2O2 cathode material synthesized in different sintering conditions

Layered structure LiNi0.6Co0.2Mn0.2O2 cathode material was synthesized via a two-step solid state reaction with industrial Ni0.6Co0.2Mn0.2(OH)2 and Li2CO3 in this paper. The samples prepared at different sintering temperatures (750–850°C) and sintering times (10–18h) were analyzed by physical and electrochemical methods to gain the optimal sintering condition, and an additional XRD Rietveld refinement was taken to get more reliable structural parameters. The results demonstrated that the higher temperature leads to larger primary particle size and severer agglomeration, while duration factor may affect the electrochemical performance rather than the structure and morphology of the materials. The optimized NCM622 material has an initial discharge capacity of 156.3mAhg−1 at 1C, whose capacity retention even reached 102.9% after 100 cycles. In addition, the three dispersed peaks (P1, P2, P3) in particle distribution analysis and RSEI, Re, Rct in electrochemical impedance spectroscopy have been separated and discussed in detail.

Environmental DNA particle size distribution from Brook Trout (Salvelinus fontinalis)

Environmental DNA (eDNA) sampling has become a widespread approach for detecting aquatic animals with high potential for improving conservation biology. However, little research has been done to determine the size of particles targeted by eDNA surveys. In this study, we conduct particle distribution analysis of eDNA from a captive Brook Trout (Salvelinus fontinalis) in a flow-through mesocosm. Our data suggest that 1.2–10-μm particles are the most common size of eDNA from Brook Trout, which is consistent with our hypotheses that eDNA in the environment is comprised of loosely aggregated smaller particles, resulting in high inter-sample heterogeneity. These findings are similar to those of a study on Common Carp (Cyprinus carpio) in lentic systems.

Experimental and numerical analysis of flow behavior and particle distribution in A356/SiCp composite casting

Flow behavior and particle distribution in an inverted U-shape A356/SiCp composite casting produced by conventional investment casting were investigated experimentally and numerically. The mold filling process was directly observed by real-time X-ray radiography and the SiCp contents in casting different parts were quantitatively measured and analyzed. Based on the Euler and Lagrangian methods, the flow behavior of composite slurry and the particle distribution were simulated. During mold filling process, eddy flow occurred at gravity part and back flow formed at horizontal part after the gravity part had filled. The predicted results of particle trajectories showed that the flow characteristic of particles were turbulence, laminar, and large eddy flow at anti-gravity, horizontal, and gravity part, respectively. For the particle distribution, the measured and predicted results showed that more particles concentrate in the central section, while fewer particles were present near the surface section along the thickness. Moreover, the particle fractions generally decreased with the increasing distance to the ingate. The simulate results were reasonably suited with experimental data.

Effects of Operating Parameters on the Structural Properties of Silver Particles Synthesized by Chemical Reduction Using Poly(N-Vinylpyrrolidone)

In this study we report the preparation and characterization of fine silver microparticles by simple chemical reduction of silver nitrate using two types of bases and poly(N-vinylpyrrolidone) as protective agent. The influence of silver nitrate concentration and the nature and concentration of bases, on the properties of the silver microparticles was investigated. The structural characteristics of microparticles were determined using x-ray diffraction, scanning electron microscopy, and particle distribution analysis. It was noticed that the structure and the shape of silver microparticles depend on the base nature and the concentration of silver nitrate added to the base. It was also noted the absence of agglomerates in the powder prepared with PVP. This polymer not only serves as both coordinating agent and stabilizing one, but also plays an important role in controlling the size and shape of metal particles.