scholarly journals The MESSy aerosol submodel MADE3 (v2.0b): description and a box model test

2014 ◽  
Vol 7 (1) ◽  
pp. 691-739
Author(s):  
J. C. Kaiser ◽  
J. Hendricks ◽  
M. Righi ◽  
N. Riemer ◽  
R. A. Zaveri ◽  
...  
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Box Model ◽  
Coarse Particle ◽  
Aerosol Size Distribution ◽  
Sea Spray ◽  
Test Case ◽  
Aerosol Dynamics ◽  
Coarse Mode ◽  
Made In

Abstract. We introduce MADE3 (Modal Aerosol Dynamics model for Europe, adapted for global applications, 3rd generation), an aerosol dynamics submodel for application within the MESSy framework (Modular Earth Submodel System). MADE3 builds on the predecessor aerosol submodels MADE and MADE-in. Its main new features are the explicit representation of coarse particle interactions both with other particles and with condensable gases, and the inclusion of hydrochloric acid (HCl)/chloride (Cl) partitioning between the gas and condensed phases. The aerosol size distribution is represented in the new submodel as a superposition of nine lognormal modes: one for fully soluble particles, one for insoluble particles, and one for mixed particles in each of three size ranges (Aitken, accumulation, and coarse mode size ranges). In order to assess the performance of MADE3 we compare it to its predecessor MADE and to the much more detailed particle-resolved aerosol model PartMC-MOSAIC in a box model simulation of an idealised marine boundary layer test case. MADE3 and MADE results are very similar, except in the coarse mode, where the aerosol is dominated by sea spray particles. Cl is reduced in MADE3 with respect to MADE due to the HCl/Cl partitioning that leads to Cl removal from the sea spray aerosol in our test case. Additionally, aerosol nitrate concentration is higher in MADE3 due to the condensation of nitric acid on coarse particles. MADE3 and PartMC-MOSAIC show substantial differences in the fine particle size distributions (sizes ≲ 2 μm) that could be relevant when simulating climate effects on a global scale. Nevertheless, the agreement between MADE3 and PartMC-MOSAIC is very good when it comes to coarse particle size distribution, and also in terms of aerosol composition. Considering these results and the well-established ability of MADE in reproducing observed aerosol loadings and composition, MADE3 seems suitable for application within a global model.

scholarly journals The MESSy aerosol submodel MADE3 (v2.0b): description and a box model test

2014 ◽  
Vol 7 (3) ◽  
pp. 1137-1157 ◽  
Author(s):  
J. C. Kaiser ◽  
J. Hendricks ◽  
M. Righi ◽  
N. Riemer ◽  
R. A. Zaveri ◽  
...  
Keyword(s):  
Particle Size ◽  
Box Model ◽  
Aerosol Size Distribution ◽  
Sea Spray ◽  
Test Case ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Aerosol Dynamics ◽  
Coarse Mode ◽  
Made In

Abstract. We introduce MADE3 (Modal Aerosol Dynamics model for Europe, adapted for global applications, 3rd generation; version: MADE3v2.0b), an aerosol dynamics submodel for application within the MESSy framework (Modular Earth Submodel System). MADE3 builds on the predecessor aerosol submodels MADE and MADE-in. Its main new features are the explicit representation of coarse mode particle interactions both with other particles and with condensable gases, and the inclusion of hydrochloric acid (HCl) / chloride (Cl) partitioning between the gas and condensed phases. The aerosol size distribution is represented in the new submodel as a superposition of nine lognormal modes: one for fully soluble particles, one for insoluble particles, and one for mixed particles in each of three size ranges (Aitken, accumulation, and coarse mode size ranges). In order to assess the performance of MADE3 we compare it to its predecessor MADE and to the much more detailed particle-resolved aerosol model PartMC-MOSAIC in a box model simulation of an idealised marine boundary layer test case. MADE3 and MADE results are very similar, except in the coarse mode, where the aerosol is dominated by sea spray particles. Cl is reduced in MADE3 with respect to MADE due to the HCl / Cl partitioning that leads to Cl removal from the sea spray aerosol in our test case. Additionally, the aerosol nitrate concentration is higher in MADE3 due to the condensation of nitric acid on coarse mode particles. MADE3 and PartMC-MOSAIC show substantial differences in the fine particle size distributions (sizes ≲ 2 μm) that could be relevant when simulating climate effects on a global scale. Nevertheless, the agreement between MADE3 and PartMC-MOSAIC is very good when it comes to coarse particle size distributions (sizes ≳ 2 μm), and also in terms of aerosol composition. Considering these results and the well-established ability of MADE in reproducing observed aerosol loadings and composition, MADE3 seems suitable for application within a global model.

scholarly journals Analysis of particle size distribution changes between three measurement sites in Northern Scandinavia

2013 ◽  
Vol 13 (4) ◽  
pp. 9401-9442 ◽  
Author(s):  
R. Väänänen ◽  
E.-M. Kyrö ◽  
T. Nieminen ◽  
N. Kivekäs ◽  
H. Junninen ◽  
...  
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Aerosol Particle ◽  
Particle Growth ◽  
Particle Formation ◽  
Aerosol Size Distribution ◽  
New Particle Formation ◽  
Air Masses ◽  
Aerosol Dynamics ◽  
Particle Sizer

Abstract. We investigated atmospheric aerosol particle dynamics in a boreal forest zone in Northern Scandinavia. We used aerosol size distribution data measured with either a Differential Mobility Particle Sizer (DMPS) or Scanning Mobility Particle Sizer (SMPS) at three stations (Värriö, Pallas and Abisko), and combined these data with the HYSPLIT air mass trajectory analysis. We compared three approaches: analysis of new particle formation events, investigation of air masses transport from the ocean to individual stations with different over-land transport times, and analysis of changes in aerosol particle size distributions during the air masses transport from one measurement station to another. Aitken mode particles were found to have an apparent average growth rate of 0.6–0.7 nm h−1 when the air masses travelled over land. Particle growth rates during the NPF events were 3–6 times higher than the apparent particle growth. When comparing aerosol dynamics between the different stations for different over-land transport times, no major differences were found except that in Abisko the new particle formation events were observed to take place in air masses having shorter over-land times than at the other stations. We speculate that this is related to the meteorological differences along the paths of air masses caused by the land surface topology. When comparing between air masses travelling the east-to-west direction to those traveling the west-to-east directions, clear differences in the aerosol dynamics were seen. Our results suggest that the condensation growth has an important role in aerosol dynamics also when new particle formation is not evident.

Determination of atmospheric aerosol particle size distribution and visibility using a mobile laboratory

1982 ◽  
Vol 60 (8) ◽  
pp. 1101-1107
Author(s):  
C. V. Mathai ◽  
A. W. Harrison
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Atmospheric Aerosols ◽  
Suspended Particle ◽  
Aerosol Size Distribution ◽  
Size Distributions ◽  
Mobile Laboratory ◽  
Mean Values ◽  
The City

As part of an ongoing general research program on the effects of atmospheric aerosols on visibility and its dependence on aerosol size distributions in Calgary, this paper presents the results of a comparative study of particle size distribution and visibility in residential (NW) and industrial (SE) sections of the city using a mobile laboratory. The study was conducted in the period October–December, 1979. An active scattering aerosol spectrometer measured the size distributions and the corresponding visibilities were deduced from scattering coefficients measured with an integrating nephelometer.The results of this transit study show significantly higher suspended particle concentrations and reduced visibilities in the SE than in the NW. The mean values of the visibilities are 44 and 97 km for the SE and the NW respectively. The exponent of R (particle radius) in the power law aerosol size distribution has a mean value of −3.36 ± 0.24 in the SE compared with the corresponding value of −3.89 ± 0.39 for the NW. These results arc in good agreement with the observations of Alberta Environment; however, they are in contradiction with a recent report published by the City of Calgary.

scholarly journals Investigation of Microbial Contamination and Physicochemical Properties of Compounded Medications in Pharmacies

2020 ◽  
Vol 26 (1) ◽  
pp. 82-93
Author(s):  
Reihaneh Radmanesh ◽  
◽  
Mohsen Nabi Meybodi ◽  
Vahid Ramezani ◽  
Maryam Akrami ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Microbial Contamination ◽  
Raw Materials ◽  
Chemical Properties ◽  
Pharmaceutical Product ◽  
Physical And Chemical ◽  
Made In ◽  
And Chemical Properties

Aims: Any pharmaceutical product made in pharmacy, hospital or factory may be contaminated with microbes. This contamination can originate from raw materials or during production. Hence, it is important to study the physical and chemical properties and stability of compounded drugs. Methods & Materials: In this study, first a specific sample of prescribed medication was ordered from 63 pharmacies in Yazd, Iran. After collecting the samples, the amount of microbial contamination, viscosity and particle size distribution and their stability were investigated and their results were compared to the standard levels. Findings: Based on the results, 31.7% of the samples had discoloration and 23.8% showed creaming phenomenon. In terms of particle size distribution, 57.1% of the samples had a 20-40 μm particle size and 49.2% had a viscosity equal to 2500-3000 centipoise. Regarding stability, 12.6% of the samples underwnet phase change at 30-40°C. About of the amount of hydroquinone in samples, 35% had acceptable amount. In 23.8% of the samples, fungal infection was observed. Conclusion: Contrary to a popular belief that the compounded medicines produced in pharmacies have microbial contamination, the results of this study showed that the microbial contamination of these compounded medications is low.

scholarly journals Neural network modelling to estimate particle size distribution based on other particle sections and meteorological parameters

2021 ◽  
Author(s):  
Pak Lun Fung ◽  
Martha Arbayani Zaidan ◽  
Ola Surakhi ◽  
Sasu Tarkoma ◽  
Tuukka Petäjä ◽  
...  
Keyword(s):  
Neural Network ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Meteorological Parameters ◽  
Aerosol Size Distribution ◽  
Sufficient Information ◽  
Electrical Mobility ◽  
Particle Sizer ◽  
Mass Concentrations

Abstract. In air quality research, often only particle mass concentrations as indicators of aerosol particles are considered. However, the mass concentrations do not provide sufficient information to convey the full story of fractionated size distribution, which are able to deposit differently on respiratory system and cause various harm. Aerosol size distribution measurements rely on a variety of techniques to classify the aerosol size and measure the size distribution. From the raw data the ambient size distribution is determined utilising a suite of inversion algorithms. However, the inversion problem is quite often ill-posed and challenging to invert. Due to the instrumental insufficiency and inversion limitations, models for fractionated particle size distribution are of great significance to fill the missing gaps or negative values. The study at hand involves a merged particle size distribution, from a scanning mobility particle sizer (NanoSMPS) and an optical particle sizer (OPS) covering the aerosol size distributions from 0.01 to 0.42 μm (electrical mobility equivalent size) and 0.3 μm to 10 μm (optical equivalent size) and meteorological parameters collected at an urban background region in Amman, Jordan in the period of 1st Aug 2016–31st July 2017. We develop and evaluate feed-forward neural network (FFNN) models to estimate number concentrations at particular size bin with (1) meteorological parameters, (2) number concentration at other size bins, and (3) both of the above as input variables. Two layers with 10–15 neurons are found to be the optimal option. Lower model performance is observed at the lower edge (0.01 

Study on the evolution of nanoparticle size distribution due to continuous injection using the sectional method

2014 ◽  
Vol 24 (8) ◽  
pp. 1803-1812 ◽  
Author(s):  
Liu Huijie ◽  
Yu Mingzhou ◽  
Yin Zhaoqin ◽  
Jiang Ying ◽  
Chen Miaogen
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Design Methodology ◽  
Aerosol Size Distribution ◽  
Source Strength ◽  
Competitive Effect ◽  
Content Type ◽  
Nanoparticle System ◽  
Continuous Injection ◽  
Continuous Source

Purpose – The purpose of this paper is to investigate competitive effect of source strength and coagulation on the evolution of aerosol size distribution with a continuous source. Design/methodology/approach – A theoretical model was proposed in which the nanoparticle population balance equation with respect to particle size was solved by the sectional method. Findings – It was found two modes appear when a nanoparticle system was injected by a continuous source. Originality/value – Through tracing the evolution of particle size distribution with different source strength, the characteristics of two modes as well as their lag-time to approach steady state were deeply investigated.

scholarly journals PARTICLE SIZE DISTRIBUTION AND AEROSOL DYNAMICS OF OIL MIST IN COMMERCIAL KITCHENS

2011 ◽  
Vol 76 (664) ◽  
pp. 547-554
Author(s):  
Yasushi KONDO ◽  
Akinobu KAWAGUCHI ◽  
Hajime YOSHINO ◽  
Shunsuke OGITA
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Aerosol Dynamics ◽  
Oil Mist

Determination of Particle-Size Distribution in GR-S Latexes

1954 ◽  
Vol 27 (4) ◽  
pp. 1051-1060 ◽  
Author(s):  
Alfred Nisonoff ◽  
W. E. Messer ◽  
L. H. Howland
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Light And Electron Microscopy ◽  
Wide Distribution ◽  
Plant Production ◽  
Particle Sizes ◽  
Laboratory Centrifuge ◽  
Made In

Abstract A method based on Stokes' law, involving the use of an ordinary laboratory centrifuge, is described for the determination of particle size distribution in GR-S latexes. It is shown to be valid by tests for reproducibility and by comparison with the results of light and electron microscopy. In applying the method, several unusually fluid high-solids latexes made in the pilot plant were found to be characterized by a wide distribution of particle sizes. Data on various latexes in plant production are reported.

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