The effects of particle size distribution on the settleability of CSOs pollutants

2001 ◽  
Vol 43 (5) ◽  
pp. 103-110 ◽  
Author(s):  
E. B. Shin ◽  
H. S. Yoon ◽  
Y. D. Lee ◽  
Y. S. Pae ◽  
S. W. Hong ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Power Law ◽  
Particle Diameter ◽  
Size Spectrum ◽  
Average Particle ◽  
Factors Affecting ◽  
Major Factors ◽  
Power Law Distributions

Over the past decades, flocculation and/or sedimentation processes have been adopted to remove pollutants from CSOs. It has been learned that major factors affecting settlement of pollutants are the particle size distribution, their settling velocities and their specific gravity. It is, therefore, a good idea to analyze the particle size distribution and settleability of CSOs pollutants in order to develop details in designing a process. Discussed in this study are pollutant characteristics of CSOs such as particle size distribution and settleability of pollutants. The power law function is applied and is found to be an effective and reliable index for expressing the particle size distribution of pollutants in CSOs. Based on the particle size spectrum analysis, the tendency toward settling and simultaneous flocculation-settling phenomenon of CSOs pollutants is described. Based on the regression analysis it is observed that the derived constants of curves representing settling velocity profile are proportional to the initial concentration of particles and to the β-values of power law distributions. It is also revealed that the simultaneous flocculation-settling processes are effectively described by the changes of the average particle diameter and of the β-values of power law distributions.

scholarly journals Particle Size Parameters of Particulate Matter Suspended in Coastal Waters and Their Use as Indicators of Typhoon Influence

2020 ◽  
Vol 12 (16) ◽  
pp. 2581
Author(s):  
Yanxia Liu ◽  
Haijun Huang ◽  
Liwen Yan ◽  
Xiguang Yang ◽  
Haibo Bi ◽  
...  
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Power Law ◽  
Average Particle Size ◽  
Dynamic Processes ◽  
Average Particle ◽  
Suspended Particulate ◽  
Near Shore

The power law particle size distribution (PSD) slope parameter is commonly used to characterize sediment fluxes, resuspension, aggregates, and settling rates in coastal and estuarine waters. However, particle size distribution metrics are also very useful for understanding sediment source and dynamic processes. In this study, a method was proposed to employ the particle size parameters commonly used in sedimentary geology (average particle size (ø), sorting, skewness, and kurtosis) as indicators of changes in sediment dynamic processes, and MODIS images were used to estimate these parameters. The particle size parameters were estimated using a Mie scattering model, Quasi-Analytical Algorithm (QAA) analysis algorithm, and least squares QR decomposition (LSQR) solution method based on the relationship between the power law distribution of the suspended particles and their optical scattering properties. The estimates were verified by field measurements in the Yellow Sea and Bohai Sea regions of China. This method provided good estimates of the average particle size (ø), sorting, and kurtosis. A greater number of wavebands (39) was associated with more accurate particle size distribution curves. Furthermore, the method was used to monitor changes in suspended particulate matter in the vicinity of the Heini Bay of China before and after the passage of a strong storm in August 2011. The particle size parameters represented the influence of a strong typhoon on the distribution of the near-shore sediment and, together with the PSD slope, comprehensively reflected the changes in the near-shore suspended particulate matter. This method not only established the relationship between remote sensing monitoring and the historical sediment record, it also extends the power law model to the application of sediment source and dynamic processes in coastal waters.

scholarly journals Robust Control of Particle Size Distribution in Aerosol Processes

2010 ◽  
Vol 5 (3) ◽  
pp. 385
Author(s):  
Zhengrong Xiang
Keyword(s):  
Particle Size ◽  
Robust Control ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
State Feedback ◽  
Particle Diameter ◽  
Population Balance ◽  
Aerosol Size Distribution ◽  
Average Particle ◽  
Aerosol Process

This paper deals with a comprehensive study on robust control of particle size distribution of fractal agglomerate in aerosol processes with simultaneous chemical reaction, nucleation, condensation and coagulation. Firstly, a general aerosol process is described by population balance and mass and energy balances, which describes the evolution of particle size distribution, continuous phase species and temperature of the aerosol system, respectively. A lognormal moment approximations of the population balance model is then presented. Then, the robust state feedback controller is designed for the aerosol process with some unknown uncertainties, the proposed controller is composed of an nominal control term and a robust control term so that it only ensures the stability of the closed-loop system, but also attenuates the effect of the unknown uncertainties on the system. A high-gain observer is adopted to estimate state variables required in the on-line implementation of the state feedback. Finally, the proposed robust controller is applied to an aerosol process for achieving an aerosol size distribution with desired geometric average particle diameter, the simulation results show the robustness properties of the controller with respect to parametric model uncertainty and unmodeled dynamics.

The Effect of Nanometer Polysilicon Material on Properties of Wax-Diesel Oil Systems

2013 ◽  
Vol 774-776 ◽  
pp. 1237-1241
Author(s):  
Ren Yuan Sun ◽  
Kun Kun Fan ◽  
Lei Wang ◽  
Xiao Meng Huang ◽  
Chao Sun
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Dispersion Model ◽  
Particle Diameter ◽  
Diesel Oil ◽  
Average Particle ◽  
Scattering Method ◽  
Average Particle Diameter ◽  
Laser Scattering

The effect of nanometer polysilicon material (NMPM) on properties of wax-diesel oil systems was experimentally studied. The particle size distribution of NMPM-diesel oil, wax-diesel oil system and wax-NMPM-diesel oil system were measured by laser scattering method. The viscosity of wax-diesel oil system was compared with that of systems with NMPM addition. A new wax growth and dispersion model was built up to analyze the mechanism for wax solubility increasing and size changing. Experiments show that the solubility of wax increases with the increase of temperature and the NMPM concentration in the wax-diesel oil system. The average particle diameter of NMPM-wax-diesel oil system is larger than that of wax-diesel oil system. The viscosity of wax-diesel oil system decreases with the NMPM addition.

Effects of Multiple Impacts and Size Distribution of Particles on Erosion Predictions Using CFD

2007 ◽  
Author(s):  
Yongli Zhang ◽  
Brenton S. McLaury ◽  
Siamack A. Shirzai
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Target Material ◽  
Average Particle ◽  
Multiple Impacts ◽  
Cfd Simulations ◽  
Erosion Damage ◽  
Wide Range

Erosion equations are usually obtained from experiments by impacting solid particles entrained in a gas or liquid on a target material. The erosion equations are utilized in CFD (Computational Fluid Dynamics) models to predict erosion damage caused by solid particle impingements. Many erosion equations are provided in terms of an erosion ratio. By definition, the erosion ratio is the mass loss of target material divided by the mass of impacting particles. The mass of impacting particles is the summation of (particle mass × number of impacts) of each particle. In erosion experiments conducted to determine erosion equations, some particles may impact the target wall many times and some other particles may not impact the target at all. Therefore, the experimental data may not reflect the actual erosion ratio because the mass of the sand that is used to run the experiments is assumed to be the mass of the impacting particles. CFD and particle trajectory simulations are applied in the present work to study effects of multiple impacts on developing erosion ratio equations. The erosion equation as well as the CFD-based erosion modeling procedure is validated against a variety of experimental data. The results show that the effect of multiple impacts is negligible in air cases. In water cases, however, this effect needs to be accounted for especially for small particles. This makes it impractical to develop erosion ratio equations from experimental data obtained for tests with sand in water or dense gases. Many factors affecting erosion damage are accounted for in various erosion equations. In addition to some well-studied parameters such as particle impacting speed and impacting angle, particle size also plays a significant role in the erosion process. An average particle size is usually used in analyzing experimental data or estimating erosion damage cases of practical interest. In petroleum production applications, however, the size of sand particles that are entrained in produced fluids can vary over a fairly broad range. CFD simulations are also performed to study the effect of particle size distribution. In CFD simulations, particle sizes are normally distributed with the mean equaling the average size of interest and the standard deviation varying over a wide range. Based on CFD simulations, an equation is developed and can be applied to account for the effect of the particle size distribution on erosion prediction for gases and liquids.

scholarly journals Particle Size Distribution of E-Cigarette Aerosols and the Relationship to Cambridge Filter Pad Collection Efficiency

2015 ◽  
Vol 26 (4) ◽  
Author(s):  
Steven L. Alderman ◽  
Chen Song ◽  
Serban C. Moldoveanu ◽  
Stephen K. Cole
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Propylene Glycol ◽  
Collection Efficiency ◽  
Transmission Measurement ◽  
Average Particle ◽  
Electrical Mobility ◽  
Total Particulate Matter

AbstractThe relatively volatile nature of the particulate matter fraction of e-cigarette aerosols presents an experimental challenge with regard to particle size distribution measure-ments. This is particularly true for instruments requiring a high degree of aerosol dilution. This was illustrated in a previous study, where average particle diameters in the 10-50 nm range were determined by a high-dilution, electrical mobility method. Total particulate matter (TPM) masses calculated based on those diameters were orders of magnitude smaller than gravimetrically determined TPM. This discrepancy was believed to result from almost complete particle evaporation at the dilution levels of the electrical mobility analysis. The same study described a spectral transmission measurement of e-cigarette particle size in an undiluted state, and reported particles from 210-380 nm count median diameter. Observed particle number concentrations were in the 10Described here is a study in which e-cigarette aerosols were collected on Cambridge filters with adsorbent traps placed downstream in an effort to capture any material passing through the filter. Amounts of glycerin, propylene glycol, nicotine, and water were quantified on the filter and downstream trap. Glycerin, propylene glycol, and nicotine were effciently captured (> 98%) by the upstream Cambridge filter, and a correlation was observed between filtration efficiency and the partial vapor pressure of each component. The present analysis was largely inconclusive with regard to filter efficiency and particle-vapor partitioning of water. [Beitr. Tabakforsch. Int. 26 (2014) 183-190]

scholarly journals Global variability of phytoplankton functional types from space: assessment via the particle size distribution

2010 ◽  
Vol 7 (3) ◽  
pp. 4295-4340 ◽  
Author(s):  
T. S. Kostadinov ◽  
D. A. Siegel ◽  
S. Maritorena
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Power Law ◽  
Seasonal Succession ◽  
Remote Sensing Data ◽  
Good Correspondence ◽  
Size Classes ◽  
Functional Types ◽  
Phytoplankton Size

Abstract. A new method of retrieving the parameters of a power-law particle size distribution (PSD) from ocean color remote sensing data was used to assess the global distribution and dynamics of phytoplankton functional types (PFT's). The method retrieves the power-law slope, ξ, and the abundance at a reference diameter, N0, based upon the shape and magnitude of the particulate backscattering coefficient spectrum. Relating the PSD to PFT's on global scales assumes that the open ocean particulate assemblage is biogenic. The retrieved PSD's can be integrated to define three size-based PFT's by the percent volume concentration contribution of three phytoplankton size classes – picoplankton (0.5–2 μm in equivalent spherical diameter), nanoplankton (2–20 μm) and microplankton (20–50 μm). Validation with in-situ HPLC diagnostic pigments results in satisfactory match-ups for the pico- and micro-phytoplankton size classes. Global climatologies derived from SeaWiFS monthly data reveal PFT and particle abundance spatial patterns that are consistent with current understanding. Oligotrophic gyres are characterized by lower particle abundance and higher contribution by picoplankton-sized particles than transitional or eutrophic regions. Seasonal succession patterns for size-based PFT's reveal good correspondence between increasing chl and percent contribution by microplankton, as well as increasing particle abundance. Long-term trends in particle abundances are generally inconclusive yet are well correlated with the MEI index indicating increased oligotrophy (i.e. lower particle abundance and increased contribution of picoplankton-sized particles) during the warm phase of an El Niño event. This work demonstrates the utility and future potential of assessing phytoplankton functional types using remote characterization of the particle size distribution.

scholarly journals Digital microscopic image application (DMIA), an automatic method for particle size distribution analysis in waste activated sludge

2021 ◽  
Author(s):  
S. Cazares ◽  
J. A. Barrios ◽  
C. Maya ◽  
G. Velásquez ◽  
M. Pérez ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Activated Sludge ◽  
Size Distribution ◽  
Particle Diameter ◽  
Diffraction Method ◽  
Laser Diffraction ◽  
Waste Activated Sludge ◽  
Equivalent Diameter ◽  
Distribution Analysis

Abstract An important physical property in environmental samples is particle size distribution. Several processes exist to measure particle diameter, including change in electrical resistance, blocking of light, the fractionation of field flow and laser diffraction (these being the most commonly used). However, their use requires expensive and complex equipment. Therefore, a Digital Microscopic Imaging Application (DMIA) method was developed adapting the algorithms used in the Helminth Egg Automatic Detector (HEAD) software coupled with a Neural Network (NN) and Bayesian algorithms. This allowed the determination of particle size distribution in samples of waste activated sludge (WAS), recirculated sludge (RCS), and pretreated sludge (PTS). The recirculation and electro-oxidation pre-treatment processes showed an effect in increasing the degree of solubilization (DS), decreasing particle size and breakage factor with ranges between 44.29%, and 31.89%. Together with a final NN calibration process, it was possible to compare results. For example, the 90th percentile of Equivalent Diameter (ED) value obtained by the DMIA with the corresponding result for the laser diffraction method. DMIA values: 228.76 μm (WAS), 111.18 μm (RCS), and 84.45 μm (PTS). DMIA processing has advantages in terms of reducing complexity, cost and time, and offers an alternative to the laser diffraction method.

Particle Size Distribution of ZrO2:Pr3+ – Influences of pH, High Power Ultrasound, Surfactant and Dopant Quantity

2007 ◽  
Vol 128 ◽  
pp. 97-100 ◽  
Author(s):  
Stephanie Möller ◽  
Janusz D. Fidelus ◽  
Witold Łojkowski
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
High Power ◽  
Average Particle Size ◽  
Sodium Dodecyl ◽  
Average Particle ◽  
Power Ultrasound ◽  
High Power Ultrasound ◽  
Influence Of Ph

The aim of the work was to examine the influence of pH, high power ultrasound, surfactant and dopant quantity on the particle size distribution of ZrO2:Pr3+, with praseodymium content varying between 0.05 and 10 %. The nanopowders were obtained via a hydrothermal microwave driven process. To establish if the dopant was located on the surface of the zirconia nanoparticles, the particle size distribution, as a function of pH, was measured to obtain an estimate of the isoelectric point of the samples. All results indicated that the dopant was concentrated on the surface: the measurements of the particle size distribution show that the pH corresponding to maximum average particle size changes towards higher values when the Pr content increases. Measurements of the particle size distribution dependency on the application of high power ultrasound and the addition of the sodium dodecyl sulphate surfactant show that, under certain conditions, there is a better stabilisation of the nanopowders in a dispersion and undesirable agglomeration is hindered.

scholarly journals Factors affecting the particle size distribution and rheology of brinzolamide ophthalmic suspensions

2020 ◽  
Vol 586 ◽  
pp. 119495 ◽  
Author(s):  
Anh Vo ◽  
Xin Feng ◽  
Deval Patel ◽  
Adil Mohammad ◽  
Darby Kozak ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Factors Affecting

Effect of the particulate morphology of resin on the gelation process of PVC plastisols

2017 ◽  
Vol 37 (8) ◽  
pp. 757-764 ◽  
Author(s):  
Yubi Ji ◽  
Zhao Yang ◽  
Min Shi ◽  
Hong Tan
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Key Factors ◽  
Factors Affecting ◽  
Gelation Process ◽  
Secondary Particles ◽  
Poly Vinyl Chloride ◽  
Opposite Behavior

Abstract The gelation process of poly(vinyl chloride) (PVC) plastisol is very important to ensure the quality of the product and is affected by the type of resins, plasticizers, and other additives. In this study, the gelation process of the as-prepared PVC plastisol was characterized by measuring the evolution of vibrational viscosity with temperature or time using a vibrational viscometer. Furthermore, the effect of some commercial resins with different particulate morphologies on the gelation process was investigated by synchronously combining scanning election microscopy and laser particle size analyses. The results of this study proved that the particle size distribution and the aggregation degree of the secondary particles of a resin are the key factors affecting the gelation process. For the resin with bimodal particle size distribution, the closer the aggregation of the secondary particles, the slower the gel speed; however, an opposite behavior was observed for the resins with unimodal particle size distribution.

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