scholarly journals The effect of fatty acid surfactants on the uptake of ozone to aqueous halogenide particles

2010 ◽  
Vol 10 (6) ◽  
pp. 15023-15054
Author(s):  
A. Rouvière ◽  
M. Ammann
Keyword(s):  
Atmospheric Pressure ◽  
Phase State ◽  
Saturated Fatty Acids ◽  
Organic Coatings ◽  
Organic Films ◽  
Condensed State ◽  
Uptake Coefficient ◽  
Straight Chain ◽  
Flow Tube ◽  
Aqueous Surface

Abstract. The reactive uptake of ozone to deliquesced potassium iodide aerosol particles coated with linear saturated fatty acids (C9, C12, C15, C18 and C20) as surfactants was studied. The experiments were performed in an aerosol flow tube at 293 K and atmospheric pressure. The uptake coefficient on pure deliquesced KI aerosol was γ=(1.10±0.20)×10−2 at 72–75% relative humidity. In presence of organic coatings, the uptake coefficient decreased significantly for long straight chain surfactants (>C15), while it was only slightly reduced for the short ones (C9, C12). We linked the kinetic results to the monolayer properties of the surfactants, and specifically to the phase state of the monolayer formed (liquid expanded or liquid condensed state). We also investigated the effect of organic films to mixed deliquesced aerosol composed of a variable mixture of KI and NaCl, which allowed determining the resistance exerted to O3 at the aqueous surface by the two longer chained surfactants pentadecanoic acid (C15) and stearic acid (C18). Finally, the effect of two-component coatings, consisting of a mixture of long and short chained surfactants, was also studied.

scholarly journals The effect of fatty acid surfactants on the uptake of ozone to aqueous halogenide particles

2010 ◽  
Vol 10 (23) ◽  
pp. 11489-11500 ◽  
Author(s):  
A. Rouvière ◽  
M. Ammann
Keyword(s):  
Fatty Acid ◽  
Saturated Fatty Acids ◽  
Organic Films ◽  
Condensed State ◽  
Uptake Coefficient ◽  
Flow Tube ◽  
Spreading Pressure ◽  
Air Water Interface ◽  
Aqueous Surface ◽  
Equilibrium Spreading Pressure

Abstract. The reactive uptake of ozone to deliquesced potassium iodide aerosol particles coated with linear saturated fatty acids (C9, C12, C15, C18 and C20) was studied. The experiments were performed in an aerosol flow tube at 293 K and atmospheric pressure. The uptake coefficient on pure deliquesced KI aerosol was γ = (1.10±0.20)×10−2 at 72–75% relative humidity. In presence of organic coatings, the uptake coefficient decreased significantly for long straight chain surfactants (≥C15), while it was only slightly reduced for the short ones (C9, C12). We linked the kinetic results to the monolayer properties of the surfactants, and specifically to the expected phase state of the monolayer formed (liquid expanded or liquid condensed state). The results showed a decrease of the uptake coefficient by 30% for C12, 85% for C15 and 50% for C18 in presence of a monolayer of a fatty acid at the equilibrium spreading pressure at the air/water interface. The variation among C12, C15 and C18 follows the density of the monolayer at equilibrium spreading pressure, which is highest for the C15 fatty acid. We also investigated the effect of organic films to mixed deliquesced aerosol composed of a variable mixture of KI and NaCl, which allowed determining the resistance exerted to O3 at the aqueous surface by the two longer chained surfactants pentadecanoic acid (C15) and stearic acid (C18). For these, the probability that a molecule hitting the surface is actually transferred to the aqueous phase underneath was βC15=6.8×10−4 and βC18 = 3.3×10−4, respectively. Finally, the effect of two-component coatings, consisting of a mixture of long and short chained surfactants, was studied qualitatively.

scholarly journals Heterogeneous reaction of N<sub>2</sub>O<sub>5</sub> with illite and Arizona test dust particles

2014 ◽  
Vol 14 (1) ◽  
pp. 245-254 ◽  
Author(s):  
M. J. Tang ◽  
G. Schuster ◽  
J. N. Crowley
Keyword(s):  
Relative Humidity ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Heterogeneous Reaction ◽  
Thermal Dissociation ◽  
Dust Particles ◽  
Mineral Surfaces ◽  
Uptake Coefficient ◽  
Flow Tube ◽  
Aerosol Flow

Abstract. The heterogeneous reaction of N2O5 with airborne illite and Arizona test dust (ATD) particles was investigated at room temperature and at different relative humidities using an atmospheric pressure aerosol flow tube. N2O5 at concentrations in the range 8 to 24 × 1012 molecule cm−3 was monitored using thermal-dissociation cavity ring-down spectroscopy at 662 nm. At zero relative humidity a large uptake coefficient of N2O5 to illite was obtained, γ(N2O5) = 0.09, which decreased to 0.04 as relative humidity was increased to 67%. In contrast, the uptake coefficient derived for ATD is much lower (~0.006) and displays a weaker (if any) dependence on relative humidity (0–67%). Potential explanations are given for the significant differences between the uptake behaviour for ATD and illite and the results are compared with uptake coefficients for N2O5 on other mineral surfaces.

scholarly journals Heterogeneous reaction of N<sub>2</sub>O<sub>5</sub> with illite and Arizona Test Dust particles

2013 ◽  
Vol 13 (9) ◽  
pp. 24855-24884 ◽  
Author(s):  
M. J. Tang ◽  
G. Schuster ◽  
J. N. Crowley
Keyword(s):  
Relative Humidity ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Heterogeneous Reaction ◽  
Thermal Dissociation ◽  
Dust Particles ◽  
Experimental Uncertainty ◽  
Mineral Surfaces ◽  
Uptake Coefficient ◽  
Flow Tube

Abstract. The heterogeneous reaction of N2O5 with airborne illite and Arizona Test Dust particles was investigated at room temperature and at different relative humidities using an atmospheric pressure aerosol flow tube. N2O5 at concentrations in the range 8 to 24×1012 molecule cm−3 was monitored using thermal-dissociation cavity ring-down spectroscopy at 662 nm. At zero relative humidity a large uptake coefficient of N2O5 to illite was obtained, γ(N2O5) = 0.09, which decreased to 0.04 as relative humidity was increased to 67%. In contrast, the uptake coefficient derived for ATD is much lower (~ 0.006) and, within experimental uncertainty, independent of relative humidity (0–67%). Potential explanations are given for the significant differences between the uptake behaviour for ATD and illite and the results are compared with uptake coefficients for N2O5 on other mineral surfaces.

scholarly journals Uptake of HO<sub>2</sub> radicals onto Arizona test dust particles using an aerosol flow tube

2014 ◽  
Vol 14 (14) ◽  
pp. 7397-7408 ◽  
Author(s):  
P. S. J. Matthews ◽  
M. T. Baeza-Romero ◽  
L. K. Whalley ◽  
D. E. Heard
Keyword(s):  
Atmospheric Pressure ◽  
Room Temperature ◽  
Reaction Times ◽  
Dust Particles ◽  
Partial Saturation ◽  
Flow Tube ◽  
Aerosol Flow ◽  
Uptake Coefficients ◽  
Gas Expansion ◽  
Dust Surface

Abstract. Uptake coefficients for HO2 radicals onto Arizona test dust (ATD) aerosols were measured at room temperature and atmospheric pressure using an aerosol flow tube and the sensitive fluorescence assay by gas expansion (FAGE) technique, enabling HO2 concentrations in the range 3–10 × 108 molecule cm−3 to be investigated. The uptake coefficients were measured as 0.031 ± 0.008 and 0.018 ± 0.006 for the lower and higher HO2 concentrations, respectively, over a range of relative humidities (5–76%). A time dependence for the HO2 uptake onto the ATD aerosols was observed, with larger uptake coefficients observed at shorter reaction times. The combination of time and HO2 concentration dependencies suggest either the partial saturation of the dust surface or that a chemical component of the dust is partially consumed whilst the aerosols are exposed to HO2. A constrained box model is used to show that HO2 uptake to dust surfaces may be an important loss pathway of HO2 in the atmosphere.

Thin organic films by atmospheric-pressure ion deposition

2004 ◽  
Vol 3 (5) ◽  
pp. 323-329 ◽  
Author(s):  
Robert Saf ◽  
Marian Goriup ◽  
Thomas Steindl ◽  
Thomas E. Hamedinger ◽  
Daniel Sandholzer ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Organic Films ◽  
Thin Organic Films ◽  
Ion Deposition

The Use of Organic Coatings to Promote Dropwise Condensation of Steam

1987 ◽  
Vol 109 (3) ◽  
pp. 768-774 ◽  
Author(s):  
K. M. Holden ◽  
A. S. Wanniarachchi ◽  
P. J. Marto ◽  
D. H. Boone ◽  
J. W. Rose
Keyword(s):  
Heat Transfer ◽  
Atmospheric Pressure ◽  
Polymer Coatings ◽  
Organic Coatings ◽  
Major Constituent ◽  
Dropwise Condensation ◽  
Test Results ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Sustained Performance

Fourteen polymer coatings were evaluated for their ability to promote and sustain dropwise condensation of steam. Nine of the coatings employed a fluoropolymer as a major constituent; four employed hydrocarbons and one a silicone. Each coating was applied to 25-mm-square by approximately 1-mm-thick metal substrates of brass, copper, copper–nickel, and titanium. While exposed to steam at atmospheric pressure, each coating was visually evaluated for its ability to promote dropwise condensation. Observations were also conducted over a period of 22,000 hr. Hardness and adhesion tests were performed on selected specimens. On the basis of sustained performance, six coatings were selected for application to the outside of 19-mm-dia copper tubes in order to perform a heat transfer evaluation. These tubes were mounted horizontally in a separate apparatus through which steam flowed vertically downward. Steam-side heat transfer coefficients were inferred from overall measurements. Test results indicate that the steam-side heat transfer coefficient can be increased by a factor of five to eight through the use of polymer coatings to promote dropwise condensation.

Toxicity of Some Straight Chain Saturated Fatty Acids to House Fly Larvae1

1965 ◽  
Vol 58 (3) ◽  
pp. 400-402 ◽  
Author(s):  
M. Sayeed Quraishi ◽  
A. J. Thorsteinson
Keyword(s):  
Fatty Acids ◽  
Saturated Fatty Acids ◽  
House Fly ◽  
Straight Chain

scholarly journals Uptake of HO<sub>2</sub> radicals onto Arizona Test Dust aerosols

2014 ◽  
Vol 14 (4) ◽  
pp. 4229-4261 ◽  
Author(s):  
P. S. J. Matthews ◽  
M. T. Baeza-Romero ◽  
L. K. Whalley ◽  
D. E. Heard
Keyword(s):  
Time Dependence ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Reaction Times ◽  
Box Model ◽  
Partial Saturation ◽  
Flow Tube ◽  
Uptake Coefficients ◽  
Gas Expansion ◽  
Dust Surface

Abstract. Uptake coefficients for HO2 radicals onto Arizona Test Dust (ATD) aerosols were measured at room temperature and atmospheric pressure using an aerosol flow tube and the sensitive Fluorescence Assay by Gas Expansion (FAGE) technique, enabling HO2 concentrations in the range 3–10 × 108 molecule cm−3 to be investigated. The uptake coefficients were measured as 0.031 ± 0.008 and 0.018 ± 0.006 for the lower and higher HO2 concentrations, respectively, over a range of relative humidities (5–76%). A time dependence for the HO2 uptake onto the ATD aerosols was observed, with larger uptake coefficients observed at shorter reaction times. The combination of time and HO2 concentration dependencies suggest either the partial saturation of the dust surface or that a chemical component of the dust is partially consumed whilst the aerosols are exposed to HO2. A constrained box model is used to show that HO2 uptake to dust surfaces may be an important loss pathway of HO2 in the atmosphere.

Atmospheric pressure plasma deposition of organic films of biomedical interest

2011 ◽  
Vol 205 ◽  
pp. S525-S528 ◽  
Author(s):  
G. Da Ponte ◽  
E. Sardella ◽  
F. Fanelli ◽  
A. Van Hoeck ◽  
R. d'Agostino ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Plasma Deposition ◽  
Atmospheric Pressure Plasma ◽  
Organic Films ◽  
Pressure Plasma ◽  
Biomedical Interest
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