Threshold silt content dependency on particle morphology (shape and size) of granular materials: review with new evidence

Introduction Seed size and shape are important factors influencing trade in pulse grains. Lentil plumpness (determined by shape and size characteristics such as seed diameter, thickness, edge curvature, etc) is an important seed characteristic commonly believed to affect dehulling quality of lentils. Physical measurements of lentil shape and size characteristics are monotonous and time consuming. Objectives The focus of this research was to develop an imaging method to measure seed size and shape characteristics for predicting dehulling efficiency of red lentils. Methods A side-mounted camera system was used to image individual lentil seeds to determine seed size and shape characteristics. Results Regression models based on image analysis measurements of seed diameter, thickness, plumpness and degree of edge roundness predicted lentil dehulling efficiency highly accurately with an R2 approaching 0.90 and root-mean-squared-error <2%. Conclusion Image analysis can be used to measure lentil seed size and shape characteristics, which in turn can predict dehulling efficiency of red lentils.

Aiming at the influence of diesel engine exhaust particle mechanical characteristics on the state characteristics, studies were carried out using atomic force microscopy, high‐resolution transmission electron microscopy, and x‐ray small‐angle scattering. The variation rules of cluster‐particle interaction force and state characteristic parameters such as particle morphology and spatial structure were discussed. According to the principle of normalization, the relationship between the mechanical and state characteristics of the particles is analyzed. The results show that as the particle size increases in the exhaust process, the attractive force Fat, adhesion Fad, and adhesion energy Wad increase between the particles, Fat from 1.27 to 1.58 nN, Fad from 3.75 to 4.38 nN, Wad from 2.17 × 10−16 to 2.44 × 10−16 J. The particles are gradually agglomerated, and the cluster size is increased, indicating a certain relationship between the mechanical characteristics of the particles and the morphology. Along the exhaust direction, the particle equivalent diameter increases, and the mechanical characteristics are enhanced, while the organic matter and moisture in the exhaust are continuously adsorbed, aggravating the aggregation and shrinkage between the particles. The scattering characteristic parameters qminand qTdecrease, qminfrom 0.34 to 0.28 and qTfrom 0.72 to 0.63, the pore structure parameters decrease, the pore number concentration decreases, the peak pore size changes from 7–9 nm to 5–6 nm, the agglomerate particle structure defects decrease and the density is increased, indicating that there is a certain relationship between the mechanical characteristics of the particles and the spatial structure.

Characterization of the phosphate adsorption and morphology of sediment particles under simulative disturbing conditions

Far-field signature of fire in low gravity: Influence of ambient oxygen content and pressure on size distribution of smoke particles

Slag formation in the grate-kiln process is a major problem for iron-ore pellet producers. It is therefore important to understand the slag formation mechanism in the grate-kiln production plant. This study initiated the investigation by in situ sampling and identifying particles in the flue gas from a full-scale 40 MW grate-kiln production plant for iron-ore pelletizing. Particles were sampled from two cases of combustion with pulverized coal and heavy fuel oil. The sampling location was at the transfer chute that was situated between the traveling grate and the rotary kiln. The particle-sampling system was set up with a water-cooled particle probe equipped with nitrogen gas dilution, cyclone, and low-pressure impactor. Sub-micrometer and fine particles were size-segregated in the impactor, while coarse particles (>6 μm) were separated with a cyclone before the impactor. Characterization of these particles was carried out with environmental scanning electron microscopy (ESEM), and the morphology of sub-micrometer particles was studied with transmission electron microscopy (TEM). The results showed that particles in the flue gas consisted principally of fragments from iron-ore pellets and secondarily of ashes from pulverized coal and heavy fuel oil combustions. Three categories of particle modes were identified: (1) sub-micrometer mode, (2) first fragmentation mode, and (3) second fragmentation mode. The sub-micrometer mode consisted of vaporized and condensed species; relatively high concentrations of Na and K were observed for both combustion cases, with higher concentrations of Cl and S from heavy fuel oil combustion but higher concentrations of Si and Fe and minor P, Ca, and Al from coal combustion. The first fragmentation mode consisted of both iron-ore pellet fines and fly ash particles; a significant increment of Fe (>65 wt %) was observed, with higher concentrations of Ca and Si during heavy fuel oil combustion but higher concentrations of Si and Al during coal combustion. The second fragmentation mode consisted almost entirely of coarse iron-ore pellet fines, predominantly of Fe (∼90 wt %). The particles in the flue gas were dominantly iron-ore fines because the second fragmentation mode contributed >96 wt % of the total mass of collected particles.

Effect of lubricant oil additive on size distribution, morphology, and nanostructure of diesel particulate matter

In this paper, the size and shape characteristics of desert sand particles were quantitatively investigated via a combination of X-CT scanning and spherical harmonics functions. The size characteristics of the desert sand particles were evaluated via the Length (L), Width (W), Thickness (T), and Volume equivalent spherical diameter (VESD). The average value of the VESD for the desert sand particle is 118.2 μm, which is much smaller than that of commonly used fine aggregate, and more than 90% particles are smaller than 150 μm. The overall shape of the desert sand particles was assessed with two aspect ratios: elongation (EI) and flatness (FI). Desert sand particles were classified into four categories: spheroid-shaped, oblate-shaped, prolate-shaped, and blade-shaped. The sphericity (S) values of the desert sand particles were distributed in a wider range, with an average sphericity of 0.85, much larger than that of commonly used fine aggregates. Through a combination of aspect ratios and sphericity analysis, it can be roughly concluded that the desert sand particles appear in more irregular shapes, but with relatively smooth surface morphology and less convex or concave parts.

In this work, we developed a method to decipher the shape message imprinted in single sediment particles, a method that would reflect the detail information of surface morphology. It uses 2D mathematical descriptions to restore and characterize 3D shape and surface morphology of sediment particles in terms of the “mathematical sediment”, so as to better understand 3D geometric characteristics reflected by single sediment particles. To prevent the simplification of morphology description and overcome the deficiencies of lower-dimensional characteristics, we proposed a concept of “mathematical sediment” in this paper. The mathematical sediment uses image analysis of scanning electron microscope photographs and complex Fourier shape analysis to describe the planar projection shape of sediment particles and further restore the 3D morphology of sediment particles through a certain combination ways. The shapes of sediment particles are controlled using Fourier coefficients to generate a variety of mathematical sediments with various shapes, which allow the realization of the description and analysis of the 3D morphology of sediment particles. The fractal theory is further used to verify the rationality of mathematical sediment. Compared with the traditional method, the mathematical sediment overcomes the lack of particle system and smooth sphere systems and can reproduce 3D irregular surfaces for the morphology analysis. The rationality verification showed that the complex surface morphology of mathematical sediment is basically similar to the surface morphology of natural sediment. The mathematical sediment can reflect the true surface characteristics of sediment particles. The characteristics of shape properties and surface morphology it conveys are consistent with the natural sediment and can be used as a research basis for the further study both in fresh water and marine.

The behavior of soils at shallow depth is studied for different particle characteristics, packing density and gravity, using both numerical and experimental methods. Higher frictional resistance is observed in angular and well-graded soils. Packing density and inter-particle coordination prevails over individual particle characteristics, and gravity has a secondary effect on the normalized foundation response.

Livestock houses are major sources of airborne particulate matter (PM), which can originate from manure, feed, feathers, skin and bedding and may contain and transport microorganisms. Improved knowledge of particle size, morphology, chemical and microbiological composition of PM in livestock houses can help identify major sources of PM and contribute to the development of appropriate source-specific reduction techniques. In rabbit production systems, however, there is limited information on specific particle characteristics. The objective of this study was to characterise airborne PM in rabbit farms in terms of morphology, chemical compositions and bacterial concentration in different size fractions. Size-fractioned PM was sampled in the air of 2 rabbit farms, 1 for fattening rabbits and 1 for reproductive does, using a virtual cascade impactor, which simultaneously collected total suspended PM (TSP), PM10 and PM2.5 size fractions. Airborne PM samples were examined by light microscopy and scanning electron microscopy combined with energy dispersive X-ray analysis. Representative samples from potential sources of PM were also collected and examined. Additionally, a methodology to extract bacteria from the collected samples of airborne PM was developed to determine the bacterial concentration per PM size fraction. Results showed that airborne PM in rabbit farms is highly complex in particle morphology, especially in size. Broken skin flakes, disintegrated particles from feed or faecal material from mechanical fracture are the main sources of airborne PM in rabbit farms. Major elements found in rabbit airborne PM were S, Ca, Mg, Na and Cl. Bacterial concentrations ranged from 1.7×10 4 to 1.6×10 6 colony forming units (CFU)/m 3 (TSP); from 3.6×10 3 to 3.0×10 4 CFU/m 3 (PM10); and from 3.1×10 3 to 1.6×10 4 CFU/m 3 (PM2.5). Our results will improve the knowledge on essential particle characteristics necessary to understand PM’s origin in rabbit farms and contribute to its reduction.

Influenza viruses are respiratory pathogens and can cause severe disease. The best protection against influenza is provided by annual vaccination. These vaccines are produced in embryonated chicken eggs or using continuous animal cell lines. The latter processes are more flexible and scalable to meet the growing global demand. However, virus production in cell cultures is more expensive. Hence, further research is needed to make these processes more cost-effective and robust. We studied influenza virus replication dynamics to identify factors that limit the virus yield in adherent Madin-Darby canine kidney (MDCK) cells. The cell cycle stage of MDCK cells had no impact during early infection. Yet, our results showed that the influenza virus RNA synthesis levels out already 4 h post infection at a time when viral genome segments are exported from the nucleus. Nevertheless, virus release occurred at a constant rate in the following 16 h. Thereafter, the production of infectious viruses dramatically decreased, but cells continued to produce particles contributing to the hemagglutination (HA) titer. The majority of these particles from the late phase of infection were deformed or broken virus particles as well as large membranous structures decorated with viral surface proteins. These changes in particle characteristics and morphology need to be considered for the optimization of influenza virus production and vaccine purification steps. Moreover, our data suggest that in order to achieve higher cell-specific yields, a prolonged phase of viral RNA synthesis and/or a more efficient release of influenza virus particles is required.Electronic supplementary materialThe online version of this article (doi:10.1007/s00253-016-7542-4) contains supplementary material, which is available to authorized users.

Suspended particles are an essential component of large rivers influencing channel geomorphology, biogeochemical cycling of nutrients, and food web resources. The Upper Mississippi River is a large floodplain river that exhibits pronounced spatiotemporal variation in environmental conditions and biota, providing an ideal environment for investigating dynamics of suspended particles in large river ecosystems. Here we investigated two questions: (i) How do suspended particle characteristics (e.g. size and morphology) vary temporally and spatially? and (ii) What environmental variables have the strongest association with particle characteristics? Water sampling was conducted in June, August, and September of 2013 and 2014 in Navigation Pool 19 of the Upper Mississippi River. A FlowCAM® (Flow Cytometer and Microscope) particle imaging system was used to enumerate and measure particles 53–300 μm in diameter for size and shape characteristics (e.g. volume, elongation, and symmetry). Suspended particle characteristics varied considerably over space and time and were strongly associated with discharge and concentrations of nitrate + nitrite (NO3−) and soluble reactive phosphorus. Particle characteristics in backwaters were distinct from those in other habitats for most of the study period, likely due to reduced hydrologic connectivity and higher biotic production in backwaters. During low discharge, phytoplankton and zooplankton made up relatively greater proportions of the observed particles. Concurrently during low discharge, concentrations of chlorophyll, volatile suspended solids, and total phosphorus were higher. Our results suggest that there are complex interactions among space, time, discharge, and other environmental variables (e.g. water nutrients), which drive suspended particle dynamics in large rivers. Copyright © 2017 John Wiley &amp; Sons, Ltd.

Computational modeling, machine learning, and statistical data analysis are increasingly utilized to mitigate chemistry, manufacturing, and control failures related to particle properties in solid dosage form manufacture. Advances in particle characterization techniques and computational approaches provide unprecedented opportunities to explore relationships between particle morphology and drug product manufacturability. Achieving this, however, has numerous challenges such as producing and appropriately curating robust particle size and shape data. Addressing these challenges requires a harmonized strategy from material sampling practices, characterization technique selection, and data curation to provide data sets which are informative on material properties. Herein, common sources of error in particle characterization and data compression are reviewed, and a proposal for providing robust particle morphology (size and shape) data to support modeling efforts, approaches for data curation, and the outlook for modeling particle properties are discussed.

Triboelectrics: The influence of particle surface roughness and shape on charge acquisition during aerosolization and the DPI performance

A typical ground investigation for characterizing geotechnical properties of soil requires sampling soils to test in a laboratory. Laboratory X-ray computed tomography (CT) has been used to non-destructively observe soils and characterize their properties using image processing, numerical analysis, or three-dimensional (3D) printing techniques based on scanned images; however, if it becomes possible to scan the soils in the ground, it may enable the characterization without sampling them. In this study, an in-situ X-ray CT scanning system comprising a drilling machine with an integrated CT scanner was developed. A model test was conducted on gravel soil to verify if the equipment can drill and scan the soil underground. Moreover, image processing was performed on acquired 3D CT images to verify the image quality; the particle morphology (particle size and shape characteristics) was compared with the results obtained for projected particles captured in a two-dimensional (2D) manner by a digital camera. The equipment successfully drilled to a target depth of 800 mm, and the soil was scanned at depths of 700, 750, and 800 mm. Image processing results showed a reasonable agreement between the 3D and 2D particle morphology images, and confirmed the feasibility of the in-situ X-ray CT scanning system.