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Liu P, Liu W, Bai P. Investigating the Influence of Varied Particle Sizes on the Load-Bearing Properties of Arrester Bed Aggregates. MATERIALS (BASEL, SWITZERLAND) 2024; 17:2271. [PMID: 38793336 PMCID: PMC11123449 DOI: 10.3390/ma17102271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 05/04/2024] [Accepted: 05/08/2024] [Indexed: 05/26/2024]
Abstract
This study employs the discrete element method to investigate the influence of particle size on the load-bearing characteristics of aggregates, with a specific emphasis on the aggregates used in escape ramp arrester beds. This study utilises the log edge detection algorithm to introduce an innovative approach for modelling irregularly shaped pebbles, integrating their physical properties into a comprehensive discrete element model to enhance the accuracy and applicability of simulations involving such pebbles. Meticulous validation and parameter calibration (friction coefficient: 0.37, maximum RMSE: 3.43) confirm the accuracy of the simulations and facilitate an in-depth examination of the mechanical interactions between aggregate particles at macroscopic and microscopic scales. The findings reveal a significant relationship between the particle size and load-bearing capacity of aggregates. Smaller pebbles, which are more flexible under pressure, can be packed more densely, thereby improving the distribution of vertical forces and increasing the concentration of local stress. This enhancement substantially increases the overall load-bearing capacity of aggregates. These discoveries hold significant implications for engineering practices, particularly in the optimisation of safety for truck escape ramps and in identifying the ideal sizes of pebbles with irregular shapes.
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Affiliation(s)
- Pan Liu
- College of Vehicle and Traffic Engineering, Henan University of Science and Technology, Luoyang 471000, China; (W.L.); (P.B.)
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Yuan B, Gan W, Sun J, Lin B, Chen Z. Depth profiles of microplastics in sediments from inland water to coast and their influential factors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166151. [PMID: 37562610 DOI: 10.1016/j.scitotenv.2023.166151] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/19/2023] [Accepted: 08/06/2023] [Indexed: 08/12/2023]
Abstract
Microplastics, plastic particles with a size smaller than 5 mm, are widely observed in the global environments and pose a growing threat as they accumulate and affect the environments in numerous ways. These particles can be transported from inland water to coast and disperse from surface water to deep sediments, especially the latter, while knowledge of the hidden microplastics in sediment layers is still lacking. Understanding the characteristics and behavior of microplastics in deep sediments from inland water to coast is crucial for estimating the present and future global plastic budget from land to seas. Herein, present knowledge of microplastic sedimentation from inland water to coast is reviewed, with a focus on the physical characteristics of microplastics and environmental factors that affect sedimentation. The abundance, shape, composition, and timeline of microplastics in sediment layers in rivers, floodplains, lakes, estuaries and coastal wetlands are presented. The abundance of microplastics in sediment layers varies across sites and may exhibit opposite trends along depth, and generally the proportion of relatively small microplastics increases with depth, while less is known about the vertical trends in the shape and composition of microplastics. Timeline of microplastics is generally linked to the sedimentation rate, which varies from millimeters to centimeters per year in the reviewed studies. The spatiotemporal characteristics of microplastic sedimentation depend on the settling and erosion of microplastics, which are determined by two aspects, microplastic characteristics and environmental factors. The former aspect includes size, shape and density influenced by aggregation and biofouling, and the latter includes dynamic forces, topographic features, bioturbation and human activities. The comprehensive review of these factors highlights the needs to further quantify the characteristics of microplastic sedimentation and explore the role of these factors in microplastic sedimentation on various spatiotemporal scales.
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Affiliation(s)
- Bing Yuan
- School of Civil Engineering, Sun Yat-sen University, 519082 Zhuhai, China; State Key Laboratory of Hydroscience and Engineering, Department of Hydraulic Engineering, Tsinghua University, 100084 Beijing, China
| | - Wenhui Gan
- School of Civil Engineering, Sun Yat-sen University, 519082 Zhuhai, China
| | - Jian Sun
- State Key Laboratory of Hydroscience and Engineering, Department of Hydraulic Engineering, Tsinghua University, 100084 Beijing, China.
| | - Binliang Lin
- State Key Laboratory of Hydroscience and Engineering, Department of Hydraulic Engineering, Tsinghua University, 100084 Beijing, China
| | - Zhihe Chen
- School of Civil Engineering, Sun Yat-sen University, 519082 Zhuhai, China.
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Winston RJ, Witter JD, Tirpak RA. Measuring sediment loads and particle size distribution in road runoff: Implications for sediment removal by stormwater control measures. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 902:166071. [PMID: 37558076 DOI: 10.1016/j.scitotenv.2023.166071] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 07/12/2023] [Accepted: 08/03/2023] [Indexed: 08/11/2023]
Abstract
Road runoff contributes an array of pollutants which degrade the quality of receiving waters. Sediment conveyed in runoff results in loss of habitat and loss of reservoir capacity, among other undesirable impacts. To select and design stormwater control measures (SCMs), the sediment particle size distribution (PSD) is needed to quantify the required hydraulic retention time for particle settling and to understand what other treatment processes (e.g., filtration) are needed to meet sediment removal targets. A two-year field monitoring study was undertaken across the state of Ohio, USA, to evaluate the PSD of sediment in runoff at twelve roads. The highest TSS concentrations were observed on interstate highways (highest annual average daily traffic [AADT]) and minor arterials (low AADT), suggesting factors beyond AADT, such as antecedent dry period, rainfall intensity, and windborne dust and particulates, contribute to the varied sediment characteristics in runoff. The median TSS load across all samples collected was 2.7 kg/ha per storm event, while annual TSS loads for the monitoring sites varied from 98 kg/(ha·yr) to 519 kg/(ha·yr), with a mean value of 271 kg/(ha·yr). Particle size distributions varied across the monitoring sites, with mean and median d50 of 48.6 μm and 52.5 μm, respectively. Interstate highways (highest AADT) had significantly finer PSDs than other functional classes, while roads in low density residential areas had coarser PSDs than other land uses. Observed differences in PSD across road characteristics may guide SCM selection; dry detention basins and wet ponds/wetlands were predicted to provide effective removal across a variety of PSDs, while TSS reductions provided by hydrodynamic separators and high-flow media filters (which effectively remove larger particles) may be maximized in areas with coarser PSDs (e.g., roads surrounded by low density residential areas studied herein).
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Affiliation(s)
- Ryan J Winston
- Department of Food, Agricultural, and Biological Engineering, The Ohio State University, 590 Woody Hayes Dr., Columbus, OH 43210, USA; Department of Civil, Environmental, and Geodetic Engineering, The Ohio State University, 2070 Neil Ave., Columbus, OH 43210, USA.
| | - Jon D Witter
- Agronomy and Soils, Agricultural Technical Institute, The Ohio State University, 1328 Dover Road, Wooster, OH 44691, USA
| | - R Andrew Tirpak
- Department of Food, Agricultural, and Biological Engineering, The Ohio State University, 590 Woody Hayes Dr., Columbus, OH 43210, USA
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Connolly BJ, Loth E, Smith CF. Efficiency of inertial particle separators. POWDER TECHNOL 2023. [DOI: 10.1016/j.powtec.2022.118004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Drag coefficients for elongated/flattened irregular particles based on particle-resolved direct numerical simulation. POWDER TECHNOL 2023. [DOI: 10.1016/j.powtec.2023.118290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Roostaee A, Faghani A, Vaezi M. On the drag coefficient of flat and non‐flat solid particles of irregular shapes; an experimental validation study. AIChE J 2022. [DOI: 10.1002/aic.17821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Amin Roostaee
- College of Engineering and Engineering Technology Northern Illinois University, Still Gym 203 DeKalb IL USA
| | - Ali Faghani
- College of Engineering and Engineering Technology Northern Illinois University, Still Gym 203 DeKalb IL USA
| | - Mahdi Vaezi
- College of Engineering and Engineering Technology Northern Illinois University, Still Gym 203 DeKalb IL USA
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Comparison of Geometric Properties of Regular and Irregular Mineral Grains by Dynamic Image Analysis (2D) and Optoelectronic Analysis (3D) Methods. MINERALS 2022. [DOI: 10.3390/min12050540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The properties of bulk materials are influenced by geometrical features of grains such as size, size distribution and shape. However, size is an ambiguous parameter for non-spherical particles. Therefore, the influence of the shape of a particle on its size, as described by various measuring methods and estimators using the main particle dimensions, was studied here. Granulometric analyses of mineral raw material samples containing regular and irregular grains were performed as part of the research. The measurements were made using two methods: the dynamic image analysis and the optoelectronic analysis. The main dimensions of the particles in 2D and 3D space were measured. Particle shape descriptors were determined based on the measurements: circularity and sphericity. Particle size distributions were also determined as a function of the minimum and maximum Feret diameters (for the 2D method) and the shortest and longest dimensions of particles recorded by the 3D method. The distribution of grain shapes according to Zingg classification was used for the 3D method. The results of the study were discussed in the context of comparing both of the measuring methods and selecting the most appropriate one to assess particle (ir)regularity.
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Castang C, Laín S, García D, Sommerfeld M. Aerodynamic coefficients of irregular non-spherical particles at intermediate Reynolds numbers. POWDER TECHNOL 2022. [DOI: 10.1016/j.powtec.2022.117341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Zhou C, Su J, Chen H, Shi Z. Terminal velocity and drag coefficient models for disc-shaped particles based on the imaging experiment. POWDER TECHNOL 2022. [DOI: 10.1016/j.powtec.2021.117062] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Lv K, Min F, Zhu J, Ren B, Bai X, Wang C. Experiments and CFD-DEM simulations of fine kaolinite particle sedimentation dynamic characteristics in a water environment. POWDER TECHNOL 2021. [DOI: 10.1016/j.powtec.2020.12.057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Settling of Road-Deposited Sediment: Influence of Particle Density, Shape, Low Temperatures, and Deicing Salt. WATER 2020. [DOI: 10.3390/w12113126] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Separation of particulate matter (PM) is the most important process to achieve a reduction of contaminants present in road runoff. To further improve knowledge about influencing factors on the settling of road-deposited sediment (RDS), samples from three sites were collected. Since particle size distribution (PSD) has the strongest effect on settling, the samples were sieved to achieve comparable PSDs so that the effects of particle density, shape, fluid temperature, and deicing salt concentration on settling could be assessed using settling experiments. Based on the experimental data, a previously proposed model that describes the settling of PM was further developed and validated. In addition, RDS samples were compared to a standard mineral material, which is currently in use to evaluate treatment efficiency of stormwater quality improvement devices. The main finding was that besides PSD, particle density is the most important influencing factor. Particle shape was thoroughly described but showed no significant improvement of the prediction of the settled mass. Temperature showed an effect on PM settling; deicing salts were negligible. The proposed models can sufficiently predict the settling of RDS in settling column experiments under varying boundary conditions and are easily applicable.
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