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ERC

NANODYNAMITE Report Summary

Project ID: 616075
Funded under: FP7-IDEAS-ERC
Country: Austria

Mid-Term Report Summary - NANODYNAMITE (Quantifying Aerosol Nanoparticle Dynamics by High Time Resolution Experiments)

ERC project 616075 under the acronym „nanoDynamite“ is dedicated to the quantification of aerosol nanoparticle dynamics by high time resolution experiments. Airborne nano-scale objects experience rapid changes of their physico-chemical properties owing to physical mechanisms such as nucleation, condensation, evaporation and coagulation. Detailed understanding of the mechanisms governing nanoparticle dynamics is therefore essential to allow for quantitative interpretation of macroscopic effects related to aerosol nanoparticle formation. In this project we develop and use cutting-edge instrumentation for the characterization of aerosol nanoparticles and investigate fundamental nucleation mechanisms.
A core aspect of nanoDynamite is the construction of a so-called DMA train that provides size distribution measurements of aerosol nanoparticles in the 1.7 – 10 nm diameter range at unprecedented time resolution. The DMA train consists of six differential mobility analyzers (DMAs) that are operated at different but fixed voltages to extract one single size per channel. Based on the response time of our detectors (condensation particle counters, CPCs) we can track the time evolution of single sizes at 1 second time resolution. A major advantage of this method is that the sampling at one size allows us to do statistical analysis of raw counts which is highly important at very low particle counts. Measurements of new particle formation at ambient conditions hardly exceed particle counts of more than five counts per minute in the lowest size channels (2 nm and below). Still we can use this information to analyze growth dynamics.
Another key research area of nanoDynamite is the in-situ characterization of nanoparticles. To this end we are using synchrotron radiation to perform small-angle x-ray scattering (SAXS) experiments on aerosol nanoparticles at ambient pressures and concentrations. The set-up includes a flow tube with variable inlet length that allows us to adjust reaction time and size distribution in the measurement region. The most challenging aspect in these experiments relates to the weak scattering contrast between air molecules (~10^19 cm^-3) and nanoparticles (~10^6-10^7 cm^-3). We therefore developed a differential background subtraction method that allows us to measure scattering signals close to the resolution limit of the beamline.
Furthermore we have investigated fundamental heterogeneous nucleation mechanisms by utilizing a newly designed versatile Size Analyzing Nuclei Counter (vSANC). Specifically we studied mass accommodation coefficients during the condensation of organic molecules and determined microscopic contact angles during the nucleation of water on Ag nanoparticles. vSANC was also utilized as a particle detector with variable cut-off diameter for the measurement of ambient new particle formation.
Overall, in the first half of the project we provided instruments and manpower to three CLOUD campaigns at CERN, Switzerland, received three beam times at the SAXS beamline at the Elettra Synchrotron, Italy, and actively participated at a spring campaign at the SMEAR II station in Hyytiälä, Finland. Our work resulted in a number of publications that can be viewed on our homepage nanodynamite.at, with several manuscripts in preparation. Also we disseminated our findings at international conferences and workshops giving in total 11 oral presentations. A movie has been made publicly available at nanodynamite.at to present our research direction to the general public.

Contact

Helmut Schaschl, (Research Management)
Tel.: +43 1427718218
E-mail
Record Number: 194402 / Last updated on: 2017-02-14
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