The process of synthesizing silica nanopowder by the gas phase thermal oxidation of tetraethylorthosilicate (TEOS) in a diffusion flame reactor was simulated using a commercial computational fluid dynamic (CFD) code. The fuel combustion process and silica particle formation and growth in the flame are modeled. The temperature, velocity and particle size distribution (PSD) fields inside the reac...

Particle nucleation In a thermal plasma reactor occurs as a high-temperature gas undergoes a cooling trajectory. Cooling leads to formation of supersaturated vapours, which causes either homogeneous or ion-induced nucleation. Detailed models have been developed for homogeneous nucleation in a plasma reactor, including discretesectional models and moment-type models. The discrete-sectional model...

The role of -pinene in aerosol nucleation and growth was investigated using the CERN CLOUD chamber, a nano scanning mobility particle sizer (nanoSMPS) and several condensation particle counters (CPCs) with different diameter cut-offs. Different oxidation conditions for -pinene – OH⋅ vs. ozone oxidation – were considered to investigate their contributions to particle nucleation and growth. Resul...

We present a meshless simulation method for multiphase fluid-particle systems using Smoothed Particle Hydrodynamics (SPH) and the Discrete Element Method (DEM). Rather than fully resolving the interstitial fluid, which is often infeasible, we use an unresolved fluid model based on the locally averaged Navier Stokes equations. A variable-h SPH formulation is used to calculate the fluid phase, wh...

Dust particle growth instability and residual dust charges in a rf discharge have been studied. Dust particles were grown by sputtering of a polymer material previously deposited on the electrodes. We show that two regimes of the dust particle growth instability exist and are characterized by their frequencies. An empirical explanation based on the assumption of different dust particle growth r...

Despite the fact that frequent aerosol formation has been observed in various locations in the atmosphere, the overall magnitude of the new particle formation as a particle source is still unclear. In order to understand the particle formation and growth processes, we investigate the magnitudes of the particle formation and growth rates at the size where the real atmospheric nucleation and acti...

Transmission electron microscopic study on the aligned carbon nanotubes has demonstrated a growth mechanism which involves two sizes of iron nanoparticles. While the small particle is catalytically active for the nucleation of the nanotube, the large particle produces the carbon atomistic species required for the growth of the nanotubes. The aligned nanotubes are believed to be the result of a ...

Atmospheric gaseous sulphuric acid was measured and its influence on particle formation and growth was investigated building on aerosol data. The measurements were part of the EU-project QUEST and took place at two different measurement sites in Northern and Central Europe (Hyytiälä, Finland, March–April 2003 and Heidelberg, Germany, March–April 2004). From a comprehensive data set including su...