scholarly journals Enhanced Polonium Concentrations in Aerosols from the Gulf Oil Producing Region and the Role of Microorganisms

2021 ◽  
Vol 18 (24) ◽  
pp. 13309
Author(s):  
Montaha Behbehani ◽  
Fernando Piedade Carvalho ◽  
Saif Uddin ◽  
Nazima Habibi
Keyword(s):  
Particle Size ◽  
Activity Concentration ◽  
Organic Component ◽  
Data Set ◽  
Size Classes ◽  
210Pb Activity ◽  
Particle Size Classes ◽  
210Po Concentration ◽  
Inorganic Components ◽  
Concentration Ratios

This study provides the first data set of 210Po and 210Pb activity concentrations in the organic and inorganic components of several particle size classes of aerosols collected at two sampling stations in Kuwait. The 210Po concentrations in the aerosols (Bq/g) were similar in all of the particle size classes, but as most (91%) of the aerosol load was made of fine fraction particles of PM0.39–2.5 µm, most of the 210Po activity was carried by this aerosol fraction. At the two sampling stations, the 210Po/210Pb activity concentration ratios in the aerosols were similar, stable around the year, and averaged 1.5 (range 1.2–1.9), much higher than the typical activity concentration ratios of these radionuclides in unmodified (background) aerosols, with Po/Pb < 0.1. The aerosol enrichment in 210Po was likely originated from the oil industry, specifically by gas flaring and oil refining in the Gulf region. Radionuclide analysis in the organic and inorganic components of aerosols showed that the 210Po concentration in the organic component was one order of magnitude higher than the 210Po concentration in the inorganic component, in contrast with 210Pb, which displayed similar concentrations in both organic and inorganic aerosol components. The 210Po carrying organic component of aerosols was investigated and it was found to be largely composed of microorganisms with high microbial and fungi diversity, with the phyla Proteobacteria, Ascomycota, and Basidiomycota being dominant among the bacteria and with Zygomycota being dominant among the fungi. Therefore, we are facing an active concentration process of the atmospheric 210Po carried out by microorganisms, which underlies the 210Po enrichment process in the organic component of aerosols. This bioconcentration of polonium in bioaerosols was unknown.

Modelling the influence of total suspended solids on E. coli removal in river water

2015 ◽  
Vol 73 (6) ◽  
pp. 1320-1332 ◽  
Author(s):  
Jueying Qian ◽  
Evelyn Walters ◽  
Peter Rutschmann ◽  
Michael Wagner ◽  
Harald Horn
Keyword(s):  
Particle Size ◽  
Large Scale ◽  
Suspended Solids ◽  
Total Suspended Solids ◽  
Sensitivity Coefficient ◽  
Fecal Indicator ◽  
E Coli ◽  
Size Classes ◽  
Sedimentation Process ◽  
Particle Size Classes

Following sewer overflows, fecal indicator bacteria enter surface waters and may experience different lysis or growth processes. A 1D mathematical model was developed to predict total suspended solids (TSS) and Escherichia coli concentrations based on field measurements in a large-scale flume system simulating a combined sewer overflow. The removal mechanisms of natural inactivation, UV inactivation, and sedimentation were modelled. For the sedimentation process, one, two or three particle size classes were incorporated separately into the model. Moreover, the UV sensitivity coefficient α and natural inactivation coefficient kd were both formulated as functions of TSS concentration. It was observed that the E. coli removal was predicted more accurately by incorporating two particle size classes. However, addition of a third particle size class only improved the model slightly. When α and kd were allowed to vary with the TSS concentration, the model was able to predict E. coli fate and transport at different TSS concentrations accurately and flexibly. A sensitivity analysis revealed that the mechanisms of UV and natural inactivation were more influential at low TSS concentrations, whereas the sedimentation process became more important at elevated TSS concentrations.

scholarly journals Hygroscopicity of aerosol and its organic component at a coastal location

2014 ◽  
Vol 14 (9) ◽  
pp. 12525-12553
Author(s):  
J. D. Yakobi-Hancock ◽  
L. A. Ladino ◽  
R. H. Mason ◽  
A. K. Bertram ◽  
C. L. Schiller ◽  
...  
Keyword(s):  
Particle Size ◽  
Chemical Speciation ◽  
Aerosol Particles ◽  
Organic Component ◽  
Particle Size Distributions ◽  
Aerosol Composition ◽  
The West ◽  
Organic Species ◽  
Condensation Nucleation ◽  
Inorganic Components

Abstract. As one aspect of the NETwork on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments (NETCARE), measurements of the cloud condensation nucleation properties of 50 and 100 nm aerosol particles were conducted at Ucluelet on the west coast of Vancouver Island in August 2013. Additionally, the size-resolved chemical speciation of two particle size ranges (42–75 nm and 78–141nm) was inferred using a combination of ion chromatography and particle size distributions. Together, this information was used to estimate the hygroscopicity parameter of the organic species contained within the ambient aerosol particles (κorg). The overall hygroscopicity parameter of the aerosol (κambient) exhibited a wide variation, ranging from 0.14 to 1.08, with the highest values arising when the organic to sulfate ratio of the aerosol composition was lowest and when the winds were from the west, i.e. off the ocean. Correspondingly, the aerosol's two-day average chemical speciation also showed variation but was consistently dominated by its organic (60 to 86% by mass) and sulfate (10 to 34% by mass) components. With derived values of κorg from 0.3 to 0.5, it is illustrated that the organic component of marine-influenced aerosol can be viewed as quite hygroscopic, somewhat more than typical continental organics but not as much as soluble inorganic components.

scholarly journals Comparative selective retention of particle size classes in the gastrointestinal tract of ponies and goats

2017 ◽  
Vol 102 (2) ◽  
pp. 429-439 ◽  
Author(s):  
J. Hummel ◽  
F. Scheurich ◽  
S. Ortmann ◽  
L. A. Crompton ◽  
M. Gerken ◽  
...  
Keyword(s):  
Particle Size ◽  
Gastrointestinal Tract ◽  
Size Classes ◽  
Selective Retention ◽  
Particle Size Classes

scholarly journals Structural and Micromechanical Properties of Ternary Granular Packings: Effect of Particle Size Ratio and Number Fraction of Particle Size Classes

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 339 ◽  
Author(s):  
Joanna Wiącek ◽  
Mateusz Stasiak ◽  
Jalal Kafashan
Keyword(s):  
Particle Size ◽  
Small Particle ◽  
Size Ratio ◽  
Small Particle Size ◽  
Coordination Numbers ◽  
Size Classes ◽  
Micromechanical Properties ◽  
Particle Size Ratio ◽  
Effect Of Particle Size ◽  
Particle Size Classes

The confined uniaxial tests of packings with discrete particle size distribution (PSD) were modeled with the discrete element method. Ternary packings of spheres with PSD uniform or nonuniform by number of particles were examined in three-dimensional (3D) system. The study addressed an effect of the particle size ratio and the particle size fraction on structural and micromechanical properties of mixtures. A study of packing structure included porosity and coordination numbers, while the investigation of micromechanical properties included distribution of normal contact forces and stress transmission through the packing. A micro-scale investigation of the effect of particle size ratio on structure and mechanics of the ternary packings revealed a strong relationship between the properties of sample and the value of parameter till its critical value was reached. A further increase in particle size ratio did not significantly affect properties of packings. Contrary to the porosity and coordination numbers, the partial stresses were highly affected by the fraction of particle size classes in ternary mixtures. The contribution of the partial stress into the global stress was determined by number fraction of particles in packings with small particle size ratio, while it was mainly determined by particle size ratio in packings with small particle size ratio.

scholarly journals Valorization of MSWI Bottom Ash as a Function of Particle Size Distribution, Using Steam Washing

2020 ◽  
Vol 12 (22) ◽  
pp. 9461
Author(s):  
Enrico Destefanis ◽  
Caterina Caviglia ◽  
Davide Bernasconi ◽  
Erica Bicchi ◽  
Renato Boero ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Particle Size ◽  
Bottom Ash ◽  
Raw Material ◽  
Size Classes ◽  
Mswi Bottom Ash ◽  
Legal Limits ◽  
Chloride Sulfate ◽  
Particle Size Classes ◽  
By Products

Treatments to reduce the leaching of contaminants (chloride, sulfate, heavy metals) into the environment from bottom ash (BA) are investigated, as a function of the ash’s particle size (s). The aim is to make BA suitable for reuse as secondary raw material, in accordance with the legal requirements. Such treatments must be economically feasible and, possibly, have to use by-products of the plant (in this case, steam in excess from the turbine). For the sake of completeness and comparison, carbonation is performed on those BA particle size classes that are not positively responsive to steam washing. BA is partitioned into four different particle size classes (s ≥ 4.75, 4.75 > s ≥ 2, 2 > s ≥ 1 and s < 1 mm, corresponding to 36, 24, 13 and 27 wt%, respectively). In the case of s ≥ 2 mm (60 wt%), steam washing is effective in reducing to under the legal limits the leaching of chlorides, sulfate and heavy metals (Zn, Cu, Cd, Pb). It has been observed that steam washing causes both removal and dissolution of thin dust adherent to the BA’s surface. BA with 2 > s ≥ 1 (~13 wt% of total BA) requires a combination of steam washing and carbonation to achieve a leaching below the legal limits. The finest BA fraction, s < 1 mm (~27 wt% of total BA), is treated by carbonation, which reduces heavy metals leaching by 85%, but it fails to sufficiently curb chlorides and sulfates.

scholarly journals Attainable Region Approach in Analyzing the Breakage Behavior of a Bed of Olivine Sand Particles: Optimizing Impact Energy and Particle Size

Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1096
Author(s):  
Endene Emmanuel ◽  
Vivi Anggraini ◽  
Agusril Syamsir ◽  
Suvash Chandra Paul ◽  
Afshin Asadi
Keyword(s):  
Particle Size ◽  
Impact Energy ◽  
Size Classes ◽  
Drop Weight ◽  
Attainable Region ◽  
Sand Particles ◽  
Particle Size Classes ◽  
Olivine Sand ◽  
The Impact ◽  
Breakage Behavior

In this study, we investigated the breakage behavior of a bed of olivine sand particles using a drop-weight impact test, with drop weights of various shapes (oval, cube, and sphere). An Attainable Region (AR) technique, which is a model-free and equipment-independent technique, was then applied to optimize the impact energy during the breakage process and also to get particles in defined particle size classes. The findings revealed that the different drop weights produce products within the three different particle size classes (feed, intermediate, and fine). A higher mass fraction of materials in the fine-sized class (−75 μm) was obtained when the spherical drop weight was used relative to the cubic and oval drop weights. The drop height was found to have a significant influence on the breakage process. The AR technique proved to be a practical approach for optimizing impact energy and particle size during the breakage of a bed of olivine particles, with potential application in sustainable soil stabilization projects.

scholarly journals Sampling and analysis of coarsely shredded mixed commercial waste. Part II: particle size-dependent element determination

2021 ◽  
Author(s):  
S. A. Viczek ◽  
L. Kandlbauer ◽  
K. Khodier ◽  
A. Aldrian ◽  
R. Sarc
Keyword(s):  
Particle Size ◽  
Chemical Elements ◽  
Size Fraction ◽  
Material Composition ◽  
Accurate Analysis ◽  
Element Determination ◽  
Size Classes ◽  
Particle Size Classes ◽  
Sampling Procedures ◽  
Composite Samples

AbstractIn contemporary waste management, sampling of waste is essential whenever a specific parameter needs to be determined. Although sensor-based continuous analysis methods are being developed and enhanced, many parameters still require conventional analytics. Therefore, sampling procedures that provide representative samples of waste streams and enable sufficiently accurate analysis results are crucial. While Part I estimated the relative sampling variabilities for material classes in a replication experiment, Part II focuses on relative sampling variabilities for 30 chemical elements and the lower heating value of the same samples, i.e., 10 composite samples screened to yield 9 particle size classes (< 5 mm–400 mm). Variabilities < 20% were achieved for 39% of element-particle size class combinations but ranged up to 203.5%. When calculated for the original composite samples, variabilities < 20% were found for 57% of the analysis parameters. High variabilities were observed for elements that are expectedly subject to high constitutional heterogeneity. Besides depending on the element, relative sampling variabilities were found to depend on particle size and the mass of the particle size fraction in the sample. Furthermore, Part I and Part II results were combined, and the correlations between material composition and element concentrations in the particle size classes were interpreted and discussed. For interpretation purposes, log-ratios were calculated from the material compositions. They were used to build a regression model predicting element concentration based on material composition only. In most cases, a prediction accuracy of ± 20% of the expected value was reached, implying that a mathematical relationship exists.

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