Measurement Techniques in Gas-Phase Tropospheric Chemistry: A Selective View of the Past, Present, and Future

Abstract. Organic material from the ocean's surface can be incorporated into sea salt aerosol particles often producing a surface film on the aerosol. Such an organic coating can reduce the mass transfer between the gas phase and the aerosol phase influencing sea salt chemistry in the marine atmosphere. To investigate these effects and their importance for the marine boundary layer (MBL) we used the one-dimensional numerical model MISTRA. We considered the uncertainties regarding the magnitude of uptake reduction, the concentrations of organic compounds in sea salt aerosols and the oxidation rate of the organics to analyse the possible influence of organic surfactants on gas and liquid phase chemistry with a special focus on halogen chemistry. By assuming destruction rates for the organic coating based on laboratory measurements we get a rapid destruction of the organic monolayer within the first meters of the MBL. Larger organic initial concentrations lead to a longer lifetime of the coating but lead also to an unrealistically strong decrease of O3 concentrations as the organic film is destroyed by reaction with O3. The lifetime of the film is increased by assuming smaller reactive uptake coefficients for O3 or by assuming that a part of the organic surfactants react with OH. With regard to tropospheric chemistry we found that gas phase concentrations for chlorine and bromine species decreased due to the decreased mass transfer between gas phase and aerosol phase. Aqueous phase chlorine concentrations also decreased but aqueous phase bromine concentrations increased. Differences for gas phase concentrations are in general smaller than for liquid phase concentrations. The effect on gas phase NO2 or NO is very small (reduction less than 5%) whereas liquid phase NO2 concentrations increased in some cases by nearly 100%. We list suggestions for further laboratory studies which are needed for improved model studies.

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Inlet Fogging of Gas Turbine Engines: Part B — Fog Droplet Sizing Analysis, Nozzle Types, Measurement and Testing

Volume 4: Turbo Expo 2002, Parts A and B ◽

10.1115/gt2002-30563 ◽

2002 ◽

Cited By ~ 16

Author(s):

Mustapha Chaker ◽

Cyrus B. Meher-Homji ◽

Thomas Mee

Keyword(s):

Gas Turbine ◽

Gas Turbines ◽

Measurement Techniques ◽

Turbine Engines ◽

Gas Turbine Engines ◽

Size Measurement ◽

The Past ◽

Testing Method ◽

Measurement And Testing ◽

Experimental And Theoretical Studies

The inlet fogging of gas turbine engines for power augmentation has seen increasing application over the past decade yet not a single technical paper treating the physics and engineering of the fogging process, droplet size measurement, droplet kinetics, or the duct behavior of droplets, from a gas turbine perspective, is available. This paper provides the results of extensive experimental and theoretical studies conducted over several years, coupled with practical aspects learned in the implementation of nearly 500 inlet fogging systems on gas turbines ranging in power from 5 to 250 MW. Part B of the paper treats the practical aspects of fog nozzle droplet sizing, measurement and testing presenting the information from a gas turbine fogging perspective. This paper describes the different measurement techniques available, covers design aspects of nozzles, provides experimental data on different nozzles and provides recommendations for a standardized nozzle testing method for gas turbine inlet air fogging.

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In-depth structural analysis of glycans in the gas phase

Chemical Science ◽

10.1039/c8sc05426f ◽

2019 ◽

Vol 10 (5) ◽

pp. 1272-1284 ◽

Cited By ~ 25

Author(s):

Eike Mucha ◽

Alexandra Stuckmann ◽

Mateusz Marianski ◽

Weston B. Struwe ◽

Gerard Meijer ◽

...

Keyword(s):

Structural Analysis ◽

High Resolution ◽

Gas Phase ◽

High Throughput ◽

Glycan Analysis ◽

The Past

Although there have been substantial improvements in glycan analysis over the past decade, the lack of both high-resolution and high-throughput methods hampers progress in glycomics.

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Electron-Induced Chemistry in the Condensed Phase

Atoms ◽

10.3390/atoms7010033 ◽

2019 ◽

Vol 7 (1) ◽

pp. 33

Author(s):

Jan Hendrik Bredehöft

Keyword(s):

Gas Phase ◽

Cross Sections ◽

Condensed Phase ◽

Theoretical Understanding ◽

The Past ◽

Long Time ◽

The Difference ◽

Molecule Interactions ◽

Multi Body ◽

Molecule Interaction

Electron–molecule interactions have been studied for a long time. Most of these studies have in the past been limited to the gas phase. In the condensed-phase processes that have recently attracted attention from academia as well as industry, a theoretical understanding is mostly based on electron–molecule interaction data from these gas phase experiments. When transferring this knowledge to condensed-phase problems, where number densities are much higher and multi-body interactions are common, care must be taken to critically interpret data, in the light of this chemical environment. The paper presented here highlights three typical challenges, namely the shift of ionization energies, the difference in absolute cross-sections and branching ratios, and the occurrence of multi-body processes that can stabilize otherwise unstable intermediates. Examples from recent research in astrochemistry, where radiation driven chemistry is imminently important are used to illustrate these challenges.

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ChemInform Abstract: Gas-Phase Tropospheric Chemistry of Volatile Organic Compounds. Part 1. Alkanes and Alkenes

ChemInform ◽

10.1002/chin.199732273 ◽

2010 ◽

Vol 28 (32) ◽

pp. no-no

Author(s):

R. ATKINSON

Keyword(s):

Volatile Organic Compounds ◽

Gas Phase ◽

Organic Compounds ◽

Tropospheric Chemistry ◽

Volatile Organic

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Soot Activation Energy for a Xylene-Fueled CVD Reactor

International Journal of Chemical Reactor Engineering ◽

10.2202/1542-6580.1388 ◽

2007 ◽

Vol 5 (1) ◽

Author(s):

Wahed Wasel ◽

Kazunori Kuwana ◽

Kozo Saito

Keyword(s):

Activation Energy ◽

Carbon Nanotube ◽

Species Composition ◽

Gas Phase ◽

Inverse Method ◽

Soot Formation ◽

Effect Of Temperature ◽

Gas Phase Reactions ◽

Concentration Data ◽

The Past

The past attempts of Arrhenius plots of carbon nanotube (CNT) yield (or CNT length) to obtain the overall activation energy for CNT formation under changing reaction temperature conditions have created substantial errors. Here we propose an inverse method to accurately account for the effect of temperature on gas-phase reactions and species composition. The overall activation energy of soot formation for a xylene-based CVD reactor was calculated and successfully compared with the measured gas-phase concentration data. Our proposed inverse method is expected to help improve the performance of CVD reactors and optimize its design.

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Intercomparison of Hantzsch and fiber-laser-induced-fluorescence formaldehyde measurements

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-7-233-2014 ◽

2014 ◽

Vol 7 (1) ◽

pp. 233-255 ◽

Cited By ~ 1

Author(s):

J. Kaiser ◽

X. Li ◽

R. Tillmann ◽

I. Acir ◽

F. Rohrer ◽

...

Keyword(s):

Linear Regression ◽

Fiber Laser ◽

Gas Phase ◽

Measurement Techniques ◽

Laser Induced Fluorescence ◽

Mixing Ratios ◽

Wet Chemical ◽

Simulation Chamber

Abstract. Two gas-phase formaldehyde (HCHO) measurement techniques, a modified commercial wet-chemical instrument based on Hantzsch Fluorimetry and a custom-built instrument based on Fiber-Laser Induced Fluorescence (FILIF), were deployed at the atmospheric simulation chamber SAPHIR to compare the instruments' performances under a range of conditions. Thermolysis of para-HCHO and ozonolysis of 1-butene were used as HCHO sources, allowing for calculations of theoretical HCHO mixing ratios. Calculated HCHO mixing ratios are compared to measurements, and the two measurements are also compared. Experiments were repeated under dry and humid conditions (RH < 2% and RH > 60%) to investigate the possibility of a water artifact in the FILIF measurements. The ozonolysis of 1-butene also allowed for the investigation of an ozone artifact seen in some Hantzsch measurements in previous intercomparisons. Results show that under all conditions the two techniques are well correlated (R2 ≥ 0.997), and linear regression statistics show measurements agree with within stated uncertainty (15% FILIF + 5% Hantzsch). No water or ozone artifacts are identified.

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Odorants and Their Contributions to Overall Odour Emission from a Landfill Leachate

10.20944/preprints201911.0289.v1 ◽

2019 ◽

Author(s):

Xinguang Wang ◽

Gavin Parcsi ◽

Eric Sivret ◽

Minh Le ◽

Richard Stuetz

Keyword(s):

Gas Chromatography ◽

Gas Phase ◽

Landfill Leachate ◽

Measurement Techniques ◽

Leachate Collection ◽

Alpha Pinene ◽

Odour Source ◽

Landfill Sites ◽

Odour Emissions ◽

Sydney Australia

As one of the important odour sources, landfill sites have drawn more and more public attentions. Odour emissions from landfill sites depend on the waste buried, operation activities, running conditions, etc. A study for finding out all possible odorous compounds from a landfill was conducted by analysing of on-site gas phase samples and emission samples from a landfill leachate in Sydney, Australia using thermal desorber – gas chromatography – mass spectrometer (TD-GC-MS) and air server – thermal desorber – gas chromatography – sulfur chemiluminoscence detector (AS-TD-GC-SCD). 49 odorants were identified from emission gas samples collected from landfill leachate collection pipe and only 8 odorants were detected from flux hood emission samples of the collected leachate sample. This indicates that more sampling and measurement techniques are always better to acquire all possible pollutants from an unknown odour source. The contributions of these odorants to overall odour emissions were also calculated based on their concentrations and odour thresholds. The top 10 odorants from leachate transportation pipe include methyl mercaptan, ethyl mercaptan, m-xylene, H2S, CS2, 1,2,3,4-tetra-methylbenzene, p-xylene, 1,2,4-trimethylbenzene, ethylbenzene and α-pinene. They contributed more than 95% to the odour in the gas accumulated in the leachate collection pipe.

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