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Full-Text Articles in Physics
Small Angle Neutron Scattering From D2o–H2o Nanodroplets And Binary Nucleation Rates In A Supersonic Nozzle, Christopher H. Heath, Kiril A. Streletzky, Barbara E. Wyslouzil, Judith Woelk, Reinhard Strey
Small Angle Neutron Scattering From D2o–H2o Nanodroplets And Binary Nucleation Rates In A Supersonic Nozzle, Christopher H. Heath, Kiril A. Streletzky, Barbara E. Wyslouzil, Judith Woelk, Reinhard Strey
Physics Faculty Publications
Small angle neutron scattering (SANS) experiments were used to characterize binary nanodroplets composed of D2O and H2O. The droplets were formed by expanding dilute mixtures of condensible vapor in a N2 carrier gas through a supersonic nozzle, while maintaining the onset of condensation at a fixed position in the nozzle. It is remarkable, given the small coherent scattering length density of light water, that even the pure H2O aerosol gave a scattering signal above background. The scattering spectra were analyzed assuming a log-normal distribution of droplets. On average, the geometric radius of the nanodroplets rg was rg=13 (±1) nm, the …
Controlling Nucleation And Growth Of Nanodroplets In Supersonic Nozzles, Kiril A. Streletzky, Yury Zvinevich, Barbara E. Wyslouzil, Reinhard Strey
Controlling Nucleation And Growth Of Nanodroplets In Supersonic Nozzles, Kiril A. Streletzky, Yury Zvinevich, Barbara E. Wyslouzil, Reinhard Strey
Physics Faculty Publications
We present the first results for a new supersonic nozzle that decouples nucleation and droplet growth, and closely controls the supersaturation and temperature during nucleation. We characterize the expansions using pressure trace measurements, and the aerosol properties using light scattering and small angle neutron scattering. We show that when nucleation and droplet growth are separated, the aerosol number density decreases, the average particle size increases, and the aerosol can be more monodisperse than that formed in a conventional nozzle. Under these conditions, we can estimate the nucleation rate J as a function of supersaturation S and temperature T directly from …