scholarly journals Particle Morphology and Size Results from the Smoke Aerosol Measurement Experiment-2

2012 ◽  
Author(s):  
David Urban ◽  
Gary Ruff ◽  
Paul Greenberg ◽  
David Fischer ◽  
Marit Meyer ◽  
...  
Keyword(s):  
Particle Morphology ◽  
Smoke Aerosol ◽  
Aerosol Measurement ◽  
Measurement Experiment

scholarly journals The Finokalia Aerosol Measurement Experiment – 2008 (FAME-08): an overview

2010 ◽  
Vol 10 (3) ◽  
pp. 6641-6679 ◽  
Author(s):  
M. Pikridas ◽  
A. Bougiatioti ◽  
L. Hildebrandt ◽  
G. J. Engelhart ◽  
E. Kostenidou ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Back Trajectory ◽  
Aerosol Composition ◽  
Air Masses ◽  
The Balkans ◽  
Aerosol Measurement ◽  
Aerosol Mass Concentration ◽  
Measurement Experiment

Abstract. A month (4 May to 8 June 2008) of ambient aerosol, air ion and gas phase sampling (Finokalia Aerosol Measurement Experiment 2008, FAME-08) was conducted at Finokalia, on the island of Crete, Greece. The purpose of the study was to characterize the physical and chemical properties of aged aerosol and to investigate new particle formation. Measurements included aerosol and air ion size distributions, size-resolved chemical composition, organic aerosol thermal volatility, water uptake and particle optical properties (light scattering and absorption). Statistical analysis of the aerosol mass concentration variations revealed the absence of diurnal patterns suggesting the lack of strong local sources. Sulfates accounted for approximately half of the particulate matter less than 1 micrometer in diameter (PM1) and organics for 26%. The PM1 organic aerosol fraction was highly oxidized with 80% water soluble. The supermicrometer particles were dominated by crustal components (50%), sea salt (24%) and nitrates (16%). The organic carbon to elemental carbon (OC/EC) ratio correlated with ozone measurements but with a one-day lag. The average OC/EC ratio for the study period was equal to 5.4. For three days air masses from North Africa resulted in a 6-fold increase of particulate matter less than 10 micrometers in diameter (PM10) and a decrease of the OC/EC ratio by a factor of 2. Back trajectory analysis, based on FLEXPART footprint plots, identified five source regions (Athens, Greece, Africa, other continental and marine), each of which influenced the PM1 aerosol composition and properties. Marine air masses had the lowest PM1 concentrations and air masses from the Balkans, Turkey and Eastern Europe the highest.

scholarly journals Measurement of the ambient organic aerosol volatility distribution: application during the Finokalia Aerosol Measurement Experiment (FAME-2008)

2010 ◽  
Vol 10 (7) ◽  
pp. 17435-17466 ◽  
Author(s):  
B. H. Lee ◽  
E. Kostenidou ◽  
L. Hildebrandt ◽  
I. Riipinen ◽  
G. J. Engelhart ◽  
...  
Keyword(s):  
Particle Density ◽  
Collection Efficiency ◽  
Eastern Mediterranean ◽  
Organic Aerosol ◽  
Accommodation Coefficient ◽  
Scanning Mobility Particle Sizer ◽  
Aerosol Dynamics ◽  
Aerosol Measurement ◽  
Measurement Experiment ◽  
Particle Sizer

Abstract. A variable residence time thermodenuder (TD) was combined with an Aerodyne Aerosol Mass Spectrometer (AMS) and a Scanning Mobility Particle Sizer (SMPS) to measure the volatility distribution of aged organic aerosol in the Eastern Mediterranean during the Finokalia Aerosol Measurement Experiment in May of 2008 (FAME-2008). A new method for the quantification of the organic aerosol volatility distribution was developed combining measurements of all three instruments together with an aerosol dynamics model. Challenges in the interpretation of ambient thermodenuder-AMS measurements include the potential resistances to mass transfer during particle evaporation, the effects of particle size on the evaporated mass fraction, the changes in the AMS collection efficiency and particle density as the particles evaporate partially in the TD, and finally potential losses inside the TD. Our proposed measurement and data analysis method accounts for all of these problems combining the AMS and SMPS measurements. The AMS collection efficiency of the aerosol that passed through the TD was found to be approximately 10% lower than the collection efficiency of the aerosol that passed through the bypass. The organic aerosol measured at Finokalia is approximately 2 orders of magnitude less volatile than fresh laboratory-generated biogenic secondary organic aerosol. This low volatility is consistent with its highly oxygenated AMS mass spectrum. The results are found to be highly sensitive to the mass accommodation coefficient of the evaporating species.

scholarly journals Measurement of the ambient organic aerosol volatility distribution: application during the Finokalia Aerosol Measurement Experiment (FAME-2008)

2010 ◽  
Vol 10 (24) ◽  
pp. 12149-12160 ◽  
Author(s):  
B. H. Lee ◽  
E. Kostenidou ◽  
L. Hildebrandt ◽  
I. Riipinen ◽  
G. J. Engelhart ◽  
...  
Keyword(s):  
Particle Density ◽  
Collection Efficiency ◽  
Eastern Mediterranean ◽  
Organic Aerosol ◽  
Accommodation Coefficient ◽  
Scanning Mobility Particle Sizer ◽  
Aerosol Dynamics ◽  
Aerosol Measurement ◽  
Measurement Experiment ◽  
Particle Sizer

Abstract. A variable residence time thermodenuder (TD) was combined with an Aerodyne Aerosol Mass Spectrometer (AMS) and a Scanning Mobility Particle Sizer (SMPS) to measure the volatility distribution of aged organic aerosol in the Eastern Mediterranean during the Finokalia Aerosol Measurement Experiment in May of 2008 (FAME-2008). A new method for the quantification of the organic aerosol volatility distribution was developed combining measurements of all three instruments together with an aerosol dynamics model. Challenges in the interpretation of ambient thermodenuder-AMS measurements include the potential resistances to mass transfer during particle evaporation, the effects of particle size on the evaporated mass fraction, the changes in the AMS collection efficiency and particle density as the particles evaporate partially in the TD, and finally potential losses inside the TD. Our proposed measurement and data analysis method accounts for all of these problems combining the AMS and SMPS measurements. The AMS collection efficiency of the aerosol that passed through the TD was found to be approximately 10% lower than the collection efficiency of the aerosol that passed through the bypass. The organic aerosol measured at Finokalia is approximately 2 or more orders of magnitude less volatile than fresh laboratory-generated monoterpene (α-pinene, β-pinene and limonene under low NOx conditions) secondary organic aerosol. This low volatility is consistent with its highly oxygenated AMS mass spectrum. The results are found to be highly sensitive to the mass accommodation coefficient of the evaporating species. This analysis is based on the assumption that there were no significant reactions taking place inside the thermodenuder.

Polar Ozone and Aerosol Measurement Experiment (POAM-II)

1994 ◽  
Author(s):  
Richard M. Bevilacqua ◽  
Eric P. Shettle ◽  
John S. Hornstein ◽  
Philip R. Schwartz ◽  
Davidson T. Chen ◽  
...  
Keyword(s):  
Aerosol Measurement ◽  
Measurement Experiment ◽  
Polar Ozone

scholarly journals Aged organic aerosol in the Eastern Mediterranean: the Finokalia Aerosol Measurement Experiment – 2008

2010 ◽  
Vol 10 (9) ◽  
pp. 4167-4186 ◽  
Author(s):  
L. Hildebrandt ◽  
G. J. Engelhart ◽  
C. Mohr ◽  
E. Kostenidou ◽  
V. A. Lanz ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
Eastern Mediterranean ◽  
Source Region ◽  
Bulk Composition ◽  
Organic Aerosol ◽  
Aerosol Measurement ◽  
Two Factors ◽  
Measurement Experiment ◽  
Total Sulfate ◽  
Significant Diurnal Variation

Abstract. Aged organic aerosol (OA) was measured at a remote coastal site on the island of Crete, Greece during the Finokalia Aerosol Measurement Experiment-2008 (FAME-2008), which was part of the EUCAARI intensive campaign of May 2008. The site at Finokalia is influenced by air masses from different source regions, including long-range transport of pollution from continental Europe. A quadrupole aerosol mass spectrometer (Q-AMS) was employed to measure the size-resolved chemical composition of non-refractory submicron aerosol (NR-PM1), and to estimate the extent of oxidation of the organic aerosol. Factor analysis was used to gain insights into the processes and sources affecting the OA composition. The particles were internally mixed and liquid. The largest fraction of the dry NR-PM1 sampled was ammonium sulfate and ammonium bisulfate, followed by organics and a small amount of nitrate. The variability in OA composition could be explained with two factors of oxygenated organic aerosol (OOA) with differing extents of oxidation but similar volatility. Hydrocarbon-like organic aerosol (HOA) was not detected. There was no statistically significant diurnal variation in the bulk composition of NR-PM1 such as total sulfate or total organic aerosol concentrations. However, the OA composition exhibited statistically significant diurnal variation with more oxidized OA in the afternoon. The organic aerosol was highly oxidized, regardless of the source region. Total OA concentrations also varied little with source region, suggesting that local sources had only a small effect on OA concentrations measured at Finokalia. The aerosol was transported for about one day before arriving at the site, corresponding to an OH exposure of approximately 4×1011 molecules cm−3 s. The constant extent of oxidation suggests that atmospheric aging results in a highly oxidized OA at these OH exposures, regardless of the aerosol source.

scholarly journals The Finokalia Aerosol Measurement Experiment – 2008 (FAME-08): an overview

2010 ◽  
Vol 10 (14) ◽  
pp. 6793-6806 ◽  
Author(s):  
M. Pikridas ◽  
A. Bougiatioti ◽  
L. Hildebrandt ◽  
G. J. Engelhart ◽  
E. Kostenidou ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Back Trajectory ◽  
Aerosol Composition ◽  
Air Masses ◽  
The Balkans ◽  
Aerosol Measurement ◽  
Aerosol Mass Concentration ◽  
Measurement Experiment

Abstract. A month (4 May to 8 June 2008) of ambient aerosol, air ion and gas phase sampling (Finokalia Aerosol Measurement Experiment 2008, FAME-08) was conducted at Finokalia, on the island of Crete, Greece. The purpose of the study was to characterize the physical and chemical properties of aged aerosol and to investigate new particle formation. Measurements included aerosol and air ion size distributions, size-resolved chemical composition, organic aerosol thermal volatility, water uptake and particle optical properties (light scattering and absorption). Statistical analysis of the aerosol mass concentration variations revealed the absence of diurnal patterns suggesting the lack of strong local sources. Sulfates accounted for approximately half of the particulate matter less than 1 micrometer in diameter (PM1) and organics for 28%. The PM1 organic aerosol fraction was highly oxidized with 80% water soluble. The supermicrometer particles were dominated by crustal components (50%), sea salt (24%) and nitrates (16%). The organic carbon to elemental carbon (OC/EC) ratio correlated with ozone measurements but with a one-day lag. The average OC/EC ratio for the study period was equal to 5.4. For three days air masses from North Africa resulted in a 6-fold increase of particulate matter less than 10 micrometers in diameter (PM10) and a decrease of the OC/EC ratio by a factor of 2. Back trajectory analysis, based on FLEXPART footprint plots, identified five source regions (Athens, Greece, Africa, other continental and marine), each of which influenced the PM1 aerosol composition and properties. Marine air masses had the lowest PM1 concentrations and air masses from the Balkans, Turkey and Eastern Europe the highest.

scholarly journals Aged organic aerosol in the Eastern Mediterranean: the Finokalia aerosol measurement experiment-2008

2010 ◽  
Vol 10 (1) ◽  
pp. 1847-1900 ◽  
Author(s):  
L. Hildebrandt ◽  
G. J. Engelhart ◽  
C. Mohr ◽  
E. Kostenidou ◽  
V. A. Lanz ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
Eastern Mediterranean ◽  
Source Region ◽  
Bulk Composition ◽  
Organic Aerosol ◽  
Time Of Day ◽  
Aerosol Measurement ◽  
Measurement Experiment ◽  
Total Sulfate ◽  
Significant Diurnal Variation

Abstract. Aged organic aerosol (OA) was measured at a remote coastal site on the island of Crete, Greece during the Finokalia Aerosol Measurement Experiment-2008 (FAME-2008), which was part of the EUCAARI intensive campaign of May 2008. The site at Finokalia is influenced by air masses from different source regions, including long-range transport of pollution from continental Europe. A quadrupole aerosol mass spectrometer (Q-AMS) was employed to measure the size-resolved chemical composition of non-refractory submicron aerosol (NR-PM1), and to estimate the extent of oxidation of the organic aerosol. Factor analysis was used to gain insights into the processes and sources affecting the OA composition. The particles were internally mixed and liquid. The largest fraction of the dry NR-PM1 sampled was ammonium sulfate and ammonium bisulfate, followed by organics and a small amount of nitrate. The variability in OA composition could be explained with two factors of oxygenated organic aerosol (OOA) with differing extents of oxidation but similar volatility. Hydrocarbon-like organic aerosol (HOA) was not detected. There was no statistically significant diurnal variation in the bulk composition of NR-PM1 such as total sulfate or total organic aerosol concentrations. However, the OA composition exhibited statistically significant diurnal variation with more oxidized OA in the afternoon. The organic aerosol was highly oxidized, regardless of the source region. Total OA concentrations also varied little with time of day, suggesting that local sources had only a small effect on OA concentrations measured at Finokalia. The aerosol was transported for about one day before arriving at the site, corresponding to an OH exposure of approximately 4×1011 molecules cm−3 s. The constant extent of oxidation suggests that atmospheric aging results in a highly oxidized OA at these OH exposures, regardless of the aerosol source.

Cryomicroscopy of multiphase latices

1991 ◽  
Vol 49 ◽  
pp. 1060-1061
Author(s):  
O. L. Shaffer ◽  
M.S. El-Aasser ◽  
C. L. Zhao ◽  
M. A. Winnik ◽  
R. R. Shivers
Keyword(s):  
Electron Microscopy ◽  
Radiation Damage ◽  
Freeze Fracture ◽  
Particle Morphology ◽  
Second Stage ◽  
Transmission Electron ◽  
Important Approach ◽  
Carbon Coated ◽  
Preparation Techniques

Transmission electron microscopy is an important approach to the characterization of the morphology of multiphase latices. Various sample preparation techniques have been applied to multiphase latices such as OsO4, RuO4 and CsOH stains to distinguish the polymer phases or domains. Radiation damage by an electron beam of latices imbedded in ice has also been used as a technique to study particle morphology. Further studies have been developed in the use of freeze-fracture and the effect of differential radiation damage at liquid nitrogen temperatures of the latex particles embedded in ice and not embedded.Two different series of two-stage latices were prepared with (1) a poly(methyl methacrylate) (PMMA) seed and poly(styrene) (PS) second stage; (2) a PS seed and PMMA second stage. Both series have varying amounts of second-stage monomer which was added to the seed latex semicontinuously. A drop of diluted latex was placed on a 200-mesh Formvar-carbon coated copper grid.

Surface energy of cellulosic materials: The effect of particle morphology, particle size, and hydroxyl number

TAPPI Journal ◽  
2015 ◽  
Vol 14 (9) ◽  
pp. 565-576 ◽  
Author(s):  
YUCHENG PENG ◽  
DOUGLAS J. GARDNER
Keyword(s):  
Particle Size ◽  
Surface Energy ◽  
Particle Morphology ◽  
Nanofibrillated Cellulose ◽  
Particle Sizes ◽  
Hydroxyl Number ◽  
Small Individual ◽  
Dispersion Component ◽  
Commercial Applications ◽  
Lower Temperature

Understanding the surface properties of cellulose materials is important for proper commercial applications. The effect of particle size, particle morphology, and hydroxyl number on the surface energy of three microcrystalline cellulose (MCC) preparations and one nanofibrillated cellulose (NFC) preparation were investigated using inverse gas chromatography at column temperatures ranging from 30ºC to 60ºC. The mean particle sizes for the three MCC samples and the NFC sample were 120.1, 62.3, 13.9, and 9.3 μm. The corresponding dispersion components of surface energy at 30°C were 55.7 ± 0.1, 59.7 ± 1.3, 71.7 ± 1.0, and 57.4 ± 0.3 mJ/m2. MCC samples are agglomerates of small individual cellulose particles. The different particle sizes and morphologies of the three MCC samples resulted in various hydroxyl numbers, which in turn affected their dispersion component of surface energy. Cellulose samples exhibiting a higher hydroxyl number have a higher dispersion component of surface energy. The dispersion component of surface energy of all the cellulose samples decreased linearly with increasing temperature. MCC samples with larger agglomerates had a lower temperature coefficient of dispersion component of surface energy.

Sign in / Sign up

Export Citation Format

Share Document