Investigating the effect of storm events on the particle size distribution in a combined sewer simulator

2005 ◽  
Vol 52 (3) ◽  
pp. 129-136 ◽  
Author(s):  
C.A. Biggs ◽  
C. Prall ◽  
S. Tait ◽  
R. Ashley
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Suspended Solids ◽  
Sediment Type ◽  
Shear Stresses ◽  
Annular Flume ◽  
Sediment Bed ◽  
Median Size ◽  
Size Of Particles ◽  
Consolidation Time

The changes in particle size of sewer sediment particles rapidly eroded from a previously deposited sediment bed are described, using a rotating annular flume as a laboratory scale sewer simulator. This is the first time that particle size distributions of eroded sewer sediments from a previously deposited sediment bed have been monitored in such a controlled experimental environment. Sediments from Loenen, The Netherlands and Dundee, UK were used to form deposits in the base of the annular flume (WL Delft Netherlands) with varying conditions for consolidation in order to investigate the effect of changing consolidation time, temperature and sediment type on the amount and size of particles eroded from a bed under conditions of increasing shear. The median size of the eroded particles did not change significantly with temperature, although the eroded suspended solids concentration was greater for the higher temperature under the same shear stresses, indicating a weaker bed deposit. An increase in consolidation time caused an increase in median size of eroded solids at higher bed shear stresses, and this was accompanied by higher suspended solids concentrations. As the shear stress increased, the solids eroded from the bed developed under a longer consolidation time (56 hours) tended towards a broad unimodal distribution, whilst the size distribution of solids eroded from beds developed under shorter consolidation times (18 or 42 hours) retained a bi- or tri-modal distribution. Using different types of sediment in the flume had a marked effect on the size of particles eroded.

Dynamic behavior of suspended pollutants and particle size distribution in highway runoff

2002 ◽  
Vol 46 (11-12) ◽  
pp. 413-418 ◽  
Author(s):  
H. Furumai ◽  
H. Balmer ◽  
M. Boller
Keyword(s):  
Heavy Metals ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Suspended Solids ◽  
Dynamic Change ◽  
First Flush ◽  
Highway Runoff ◽  
Runoff Rate ◽  
Highway Drainage

Continuous runoff quality monitoring was conducted for one month at urban highway drainage with an area of 8.4 ha. Dynamic change of suspended solids and heavy metal concentrations were investigated during first flush periods, taking the particle size distribution into consideration. Except for Pb, the concentrations of TSS and heavy metals in runoff were within the range of the EMC reported in recent highway runoff research. Particle-bound heavy metals (Zn, Pb, and Cu) accounted for more significant pollutant loads than soluble fractions. Their content decreased with increasing total SS concentration in runoff samples. The results of particle size distribution (PSD) analysis of runoff samples indicate that high TSS concentration samples contained coarser particles. Based on the PSD results, a stepwise wash-off phenomenon of TSS under varying runoff rate conditions was explained by the different washoff behavior of fine (< 20 mm) and coarser particles.

scholarly journals The Study of Particle Size Distribution of Micronized Oat Bran Layer

2020 ◽  
Vol 24 (2) ◽  
pp. 45-54
Author(s):  
Dariusz Dziki ◽  
Wojciech Tarasiuk ◽  
Grzegorz Łysiak ◽  
Paweł Jochymek
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Laser Light ◽  
Rotation Speed ◽  
Raw Material ◽  
Coarse Particles ◽  
Oat Bran ◽  
Size Of Particles ◽  
Sense Of Touch

AbstractThe aim of this work was to study the particle size distribution of micronized oat bran. An impact classified mill was used to pulverizing. Before the pulverizing raw material was sterilized using overheated steam at 150°C during 3.5 min. The moisture of bran after sterilization decreased from 7.2 to about 3.9%. Five speeds of the rotor disc were used: 2600, 2970, 3340, and 3710 rpm. For each speed of the rotor disc the following speeds of classifier wheel were applied: 480, 965, 1450, 1930, 2410 and 2890 rpm. The particle size distribution of oat bran layer was measured by laser light scattering. Moreover, the sense of touch of coarse particles of micronized oat bran on a tongue was assessed according to five point scale. The largest fragmentation of the oat bran was obtained at a disc speed of 3710 rpm and at a classifier rotation speed of 1930 rpm, whereas the most coarse particles were obtained when these parameters were 3340 rpm and 480 rpm, respectively. On the other hand, the highest uniformity in size of particles in size was observed when the lowest speed of disc and classifier were used. Moreover, for the most samples the pulverized particles of oat bran were almost not discernible on tongue.

On the Regularities of the Concentration Profile of Asbestos-Cement Dust, its Particle Size Distribution Depending on the Height of Working Room and the Methods of Air Exchange Organization

2018 ◽  
Vol 875 ◽  
pp. 187-190 ◽  
Author(s):  
Valery N. Azarov ◽  
I.V. Stefanenko ◽  
R.A. Burkhanova
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Concentration Profile ◽  
Dust Particles ◽  
Cement Dust ◽  
Median Size ◽  
Asbestos Cement ◽  
Air Exchange

The dependences of the concentration profile and the particle size distribution of asbestos-cement dust on the dimensions of working room along the horizontal and vertical axes were obtained in the work. The paper considers the dependence of the median size values of dust particles on the methods of air exchange organization in the working room.

scholarly journals Shape and Size of Particles Scaled from Concrete Surfaces during Salt Frost Testing and Rapid Freeze/thaw in Water

2021 ◽  
Vol 64 (1) ◽  
pp. 53-68
Author(s):  
Marte Beheim Brun ◽  
Andrei Shpak ◽  
Stefan Jacobsen
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Test Methods ◽  
Internal Damage ◽  
Flake Thickness ◽  
Freeze Thaw ◽  
Salt Scaling ◽  
Scale Particle ◽  
Size Of Particles ◽  
Air Void

Abstract Thickness (T), Length (L), Width (W) and size distribution of scaled concrete particles in frost testing were measured. T (mm) increases with particle size surprisingly similarly for different concrete qualities and frost test methods. 2T/(L+W) reduces as function of size and is lowest for the largest particles of the salt scaling test: 0.1 – 0.15 but increases if large aggregate particles scale. Particle size distributions from salt frost testing peak for particles of 1-2 mm. The particles are flakier compared to particles from freeze/thaw in water which also have flatter size distribution no matter type of concrete or degree of damage. Scaling in water is not so efficiently reduced by air voids despite protecting very efficiently against internal damage and scaling in salt frost testing. Comparisons with T predicted by the glue spall model (≈3/4 × ice thickness) and the air void dependent (≈3× critical air void spacing) model proposed by Fagerlund are difficult due to the size dependent flake thickness. Image analysis could well describe shape. Further studies of concrete flake thickness scaled at varying thickness of ice layers are proposed.

scholarly journals Effect of the particle-size distribution variability on the SWCC predictions of coarse-grained materials

2021 ◽  
Vol 337 ◽  
pp. 02010
Author(s):  
Roberto Alves ◽  
Gilson de F.N. Gitirana ◽  
Sai K. Vanapalli
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Characteristic Curve ◽  
Strong Relationship ◽  
Coarse Grained ◽  
Sieve Analysis ◽  
Testing Procedures ◽  
Coefficient Of Uniformity ◽  
Size Of Particles

The particle-size distribution (PSD) is the key information required by several models for prediction of the soil-water characteristic curve (SWCC). The performance of these models has been extensively investigated in the literature; however, limited studies have been undertaken with respect to the uncertainty associated with the SWCC predictions resulting from the variability in the PSD. This study aims to investigate the influence of the variability of the PSD in the prediction of SWCCs using five different models applied to three different glass beads (GBs). The PSD curves were determined by sieve analysis, laser diffraction, and image analysis. The various testing procedures were statistically evaluated to understand the influence of variability of the PSD in terms of the coefficient of uniformity (CU) and de size of particles corresponding to 10% in the PSD (D10). For each prediction model, a combination of PSD curves and their coefficient of variation were used to estimate the SWCCs. Both the CU and D10 proved to have a strong relationship with the predicted SWCCs. The CU appears to influence more the residual suction prediction while the D10 seems to have a major role for the transition and residual stages.

Particle size distribution mathematical models and properties of suspended solids in a typical freshwater pond

2018 ◽  
Vol 241 ◽  
pp. 164-171 ◽  
Author(s):  
Weijun Bao ◽  
Songming Zhu ◽  
Shuirong Guo ◽  
Li Wang ◽  
Shixue Huang ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Mathematical Models ◽  
Size Distribution ◽  
Suspended Solids ◽  
Freshwater Pond
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