Effects of Particle and Bubble Diameters on Removal Rate of Hydrophilic Fine Particles in Bubbly Flows

2021 ◽  
Author(s):  
Masatoshi Kawabata ◽  
Kosuke Hayashi ◽  
Ryo Kurimoto ◽  
Akio Tomiyama
Keyword(s):  
Fine Particles ◽  
Removal Rate ◽  
Bubbly Flows

scholarly journals Episode-Based Analysis of Size-Resolved Carbonaceous Aerosol Compositions in Wintertime of Xinxiang: Implication for the Haze Formation Processes in Central China

2020 ◽  
Vol 10 (10) ◽  
pp. 3498 ◽  
Author(s):  
Guangxuan Yan ◽  
Jingwen Zhang ◽  
Puzhen Zhang ◽  
Zhiguo Cao ◽  
Guifen Zhu ◽  
...  
Keyword(s):  
Fine Particles ◽  
Removal Rate ◽  
Meteorological Condition ◽  
Central China ◽  
Carbonaceous Aerosol ◽  
Biomass Combustion ◽  
Evolution Pattern ◽  
Dry Conditions ◽  
Haze Formation ◽  
Pm2.5 And Pm10

To provide a comprehensive understanding of carbonaceous aerosol and its role in the haze formation in the Central Plains Urban Agglomeration of China, size-segregated particulate matter samples (PM1, PM2.5 and PM10) were continually collected from 20 December 2017, to 17 January 2018, in Xinxiang, the third largest city of Henan province. The results showed that the mean mass concentrations of PM1, PM2.5 and PM10 were 63.20, 119.63 and 211.95 μg·m−3, respectively, and the organic carbon (OC) and elemental carbon (EC) were 11.37 (5.87), 19.24 (7.36), and 27.04 (10.27) μg·m−3, respectively. Four pollution episodes that were categorized by short evolution patterns (PE1 and PE3) and long evolution patterns (PE2 and PE4) were observed. Meteorological condition was attributed to haze episodes evolution pattern. Carbonaceous components contributed to PE1 and PE2 under drier condition through transportation and local combustion emission, while they were not main species in PE3 and PE4 for haze explosive growth under suitable RH, whatever for the short or long evolution pattern. The atmospheric self-cleaning processes were analyzed by a case study, which showed the wet scavenging effectively reduced the coarse particles with a removal rate of 73%, while it was not for the carbonaceous components in fine particles that is hydrophobic in nature. These results highlight that local primary emissions such as biomass combustion were the important sources for haze formation in Central China, especially in dry conditions.

Research on Producing New Ceramic Filter Media Modified at Surface and its Application in Pre-Treating Slightly-Polluted Water

2011 ◽  
Vol 105-107 ◽  
pp. 1736-1741
Author(s):  
Yan Qing Zhang ◽  
Meng Li
Keyword(s):  
Iron Oxide ◽  
Oxide Film ◽  
Fine Particles ◽  
Ph Value ◽  
Removal Rate ◽  
Ceramic Filter ◽  
Polluted Water ◽  
Organic Substances ◽  
Filter Media ◽  
Quality Of Water

Using Fe (NO3)3 as modifying agent, a new porous environmental ceramic filter is modified at surface to pre-treat slightly-polluted water. It can effectively reduce organic substances in subsequent processes, thus enhance the quality of water output. The iron oxide / modified ceramic filter media was manufactured by heating vaporization, and the optimal modification conditions were as follows: pH value is seven, Fe (NO3)3 density is 2mol/L, and roasting temperature is 550 centigrade. Compared with plain ceramic filter media, the removal rate of COD was enhanced six to eight times. The surface morphology of filter media was inspected by SEM, which showed that the iron oxide film, being fine particles, was attached to the ceramic filter. This is beneficial for enhancing adsorption capability. The matter species of iron oxide film were analyzed by XRD, result showed that it contains α-Fe2O3 and α-FeOOH, which is helpful for adsorbing and removing organic substances in water.

The potential role of large, fast-sinking particles in clearing nepheloid layers

1990 ◽  
Vol 331 (1616) ◽  
pp. 103-117 ◽  
Keyword(s):  
Potential Role ◽  
Fine Particles ◽  
Removal Rate ◽  
Reynolds Numbers ◽  
Marine Snow ◽  
Particle Properties ◽  
Theoretical Predictions ◽  
Predicted Values ◽  
Contact Efficiency

The concentration of fine 0(1pm) suspended sediment in deep-sea nepheloid layers is roughly 10 5 particles cm -3 . Given this concentration, aggregation theory dictates that marine snow particles must remove fine particles at a rate of 3.5 x 10 -4 particles cm -3 s -1 for scavenging of small particles by large, fast-sinking ones to play a significant role in deposition from nepheloid layers. Assuming that one in every 10 fine particles that collide with a marine snow particle sticks to it, to achieve the above removal rate given a marine snow concentration of 10 -4 particles cm -3 requires contact efficiencies of 10 -1 to 10 -2 . Such values of contact efficiency are significantly larger than theoretical predictions of contact efficiency, but are supported by evidence from studies of radionuclide fluxes and particle size distributions. Discrepancies between inferred and predicted values of contact efficiency arise from differences in actual and model particle properties. Contact by direct interception potentially is enhanced by roughened particle surfaces and by wake capture. Wake capture is the process whereby fine particles are entrained in the recirculating eddies present behind settling particles with Reynolds numbers greater than one.

scholarly journals Aerosol size-dependent below-cloud scavenging by rain and snow in the ECHAM5-HAM

2009 ◽  
Vol 9 (2) ◽  
pp. 7873-7925 ◽  
Author(s):  
B. Croft ◽  
U. Lohmann ◽  
R. V. Martin ◽  
P. Stier ◽  
S. Wurzler ◽  
...  
Keyword(s):  
Climate Model ◽  
Fine Particles ◽  
Removal Rate ◽  
Lower Troposphere ◽  
Sea Salt ◽  
Radiative Forcings ◽  
Nucleation Mode ◽  
Size Dependent ◽  
Cloud Scavenging ◽  
Global Mean

Abstract. Wet deposition processes are highly efficient in the removal of aerosols from the atmosphere, and thus strongly influence global aerosol concentrations, and clouds, and their respective radiative forcings. In this study, physically detailed size-dependent below-cloud scavenging parameterizations for rain and snow are implemented in the ECHAM5-HAM global aerosol-climate model. Previously, below-cloud scavenging by rain in the ECHAM5-HAM was simply a function of the aerosol mode, and then scaled by the rainfall rate. The below-cloud scavenging by snow was a function of the snowfall rate alone. The global mean aerosol optical depth, and sea salt burden are sensitive to the below-cloud scavenging coefficients, with reductions near to 15% when the more vigorous size-dependent below-cloud scavenging by rain and snow is implemented. The inclusion of a prognostic rain scheme significantly reduces the fractional importance of below-cloud scavenging since there is higher evaporation in the lower troposphere, increasing the global mean sea salt burden by almost 15%. Thermophoretic effects are shown to produce increases in the global and annual mean below-cloud number removal of Aitken size particles of near to 15%, but very small increases (near 1%) in the global mean below-cloud mass scavenging of carbonaceous and sulfate aerosols. Changes in the assumptions about the below-cloud scavenging of ultra-fine particles by rain do not cause any significant changes to the global mean aerosol mass or number burdens, despite a change in the below-cloud number removal rate for nucleation mode particles by near to 10%. For nucleation mode particles, changes to the assumptions about the below-cloud scavenging by snow produce a greater change in the number removal rate, in excess of one order of magnitude. Closer agreement with different observations is found when the more physically detailed below-cloud scavenging parameterization is employed in the ECHAM5-HAM model.

Modification of Fly Ash by Sodium Tetraethylenepentamine-multi Dithiocarbamate and its Removing Performance towards Cu(II)

2011 ◽  
Vol 421 ◽  
pp. 71-76 ◽  
Author(s):  
Li Hua Liu ◽  
Bo Li ◽  
Jing Cao ◽  
Zhi Hua Zhou
Keyword(s):  
Fly Ash ◽  
Treatment Cost ◽  
Fine Particles ◽  
Removal Rate ◽  
Pozzolanic Reaction ◽  
High Specific Surface Area ◽  
Porous Crystal ◽  
Simulated Wastewater ◽  
Modified Fly Ash ◽  
Scanning Electron

A modified fly ash (MFA) was prepared from fly ash (FA) and tetraethylenepentamine-multi dithiocarbamate (TEPAMDT). The structure of MFA was characterized by FTIR, and the morphology was observed by using scanning electron microscope (SEM). Its removal perfermance towards heavy metals was assessed by employing it to the treatment of simulated wastewater containing Cu2+ and comparing with TETAMDT. The results show that the fine particles in FA assemble to form a porous crystal with high specific surface area after being modified due to the pozzolanic reaction. The dosage of MFA is far lower than that of FA and the treatment cost is less than that of TEPAMDT. The removal rate of Cu2+ can reach 100% at the dosage of MFA 412 mg/L when the Cu2+ simulated wastewater concentration is 50 mg/L. Compared with TEPAMDT, using MFA can not only increase the sedimentation rate of flocs but also reduce the volume of precipitates, and the MFA-Cu precipitate obtained is more stable than TEPAMDT-Cu in acid solution and would not cause the threat of instantly releasing heavy metal under weak acidic and alkaline environment.

Removal Rate of Hydrophobic Fine Particles in Bubbly Flow

2021 ◽  
Author(s):  
Masatoshi Kawabata ◽  
Ryo Kurimoto ◽  
Kosuke Hayashi ◽  
Akio Tomiyama
Keyword(s):  
Fine Particles ◽  
Removal Rate ◽  
Bubbly Flow

Lamella settlers for storm water treatment – performance and design recommendations

2013 ◽  
Vol 69 (2) ◽  
pp. 278-285 ◽  
Author(s):  
Stephan Fuchs ◽  
Ingo Mayer ◽  
Bernd Haller ◽  
Hartmut Roth
Keyword(s):  
Removal Efficiency ◽  
Suspended Solids ◽  
Fine Particles ◽  
Removal Rate ◽  
Total Suspended Solids ◽  
Surface Load ◽  
Surface Loading ◽  
Definition Of ◽  
Event Basis

Three lamella settlers were monitored over a period of 4 years. The main objective was to determine removal efficiencies for total suspended solids and associated pollutants. For this purpose a new sampling method based on large volume solid samplers was developed allowing a detailed analysis of solids. With regard to total suspended solids the average removal efficiency of the plants range from 49 to 68%. Similar values could be achieved for phosphorus and heavy metals mainly because of the high portion of fine particles in treatment plants' influent. A clear dependency between solid removal efficiency and the parameters maximum surface load and influent concentration could be observed on a single event basis. The aggregation of all findings result in a recommended maximum design surface loading rate (SLR) of 4 m/h. A solid removal rate of 50%, which is defined as minimum long-term efficiency, can be achieved safely at this SLR. In addition to the definition of the maximum SLR, a proper dissipation of the inflow energy and an equal collection of the clear water above the lamellas turn out to be essential.

Cytoplasmic Organization in the Receptor Cells of the Crista Ampullaris

1972 ◽  
Vol 30 ◽  
pp. 60-61 ◽  
Author(s):  
Robert F. Dunn
Keyword(s):  
Fine Particles ◽  
Apical Cell ◽  
Apical Region ◽  
Receptor Cells ◽  
Cuticular Plate ◽  
Morphological Organization ◽  
Crista Ampullaris ◽  
Cytoplasmic Organization ◽  
High Degree ◽  
General Appearance

Receptor cells of the cristae in the vestibular labyrinth of the bullfrog, Rana catesbiana, show a high degree of morphological organization. Four specialized regions may be distinguished: the apical region, the supranuclear region, the paranuclear region, and the basilar region.The apical region includes a single kinocilium, approximately 40 stereocilia, and many small microvilli all projecting from the apical cell surface into the lumen of the ampulla. A cuticular plate, located at the base of the stereocilia, contains filamentous attachments of the stereocilia, and has the general appearance of a homogeneous aggregation of fine particles (Fig. 1). An accumulation of mitochondria is located within the cytoplasm basal to the cuticular plate.

Bright-Field Images (Ctem) of Phase Objects at High Resolution

1976 ◽  
Vol 34 ◽  
pp. 490-491 ◽  
Author(s):  
Sumio Iijima
Keyword(s):  
High Resolution ◽  
Electron Beam Irradiation ◽  
Fine Particles ◽  
High Resolution Electron Microscopy ◽  
Good Test ◽  
Resolution Electron ◽  
Single Crystal Films ◽  
Crystal Films ◽  
By Products ◽  
Test Objects

We have developed a technique to prepare thin single crystal films of graphite for use as supporting films for high resolution electron microscopy. As we showed elsewhere (1), these films are completely noiseless and therefore can be used in the observation of phase objects by CTEM, such as single atoms or molecules as a means for overcoming the difficulties because of the background noise which appears with amorphous carbon supporting films, even though they are prepared so as to be less than 20Å thick. Since the graphite films are thinned by reaction with WO3 crystals under electron beam irradiation in the microscope, some small crystallites of WC or WC2 are inevitably left on the films as by-products. These particles are usually found to be over 10-20Å diameter but very fine particles are also formed on the film and these can serve as good test objects for studying the image formation of phase objects.

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