pictos_nano_animations  pictos_nano_videos  pictos_nano_cartoons  pictos_nano_quiz
 animations  videos  cartoons  quiz

Synthesis

How to assess air movements?

Invisible to the human eye, these nanoparticles are "naturally" in large quantities and variable. To assess their movements, we should preferentially follow the movements of air and try to pinpoint the colder areas and the static electric charges.

216_synthese_bis

Comparison between the parameters of nanoparticles behavior.

In addition to the movements of air, the different influences that determine their behavior dependent on the size of nanoparticles. In the range 10 - 100 nm, the force of gravity is always negligible compared with the thermal diffusion. However, the effects thermophoresis and especially electrostatic will be dominant.

Points to remember:

  • "thin" particle of a few micrometers is deposited on the ground by sedimentation in several seconds: in the absence of thermal diffusion, it would take several days per nanoparticle,
  • nanoparticles tend to be transported farther than the larger particles in an open environment,
  • in a closed environment, as they are not subject to gravity, they will stay suspended longer than heavier particles in the work atmosphere,
  • by diffusion, thermophoresis or electrostatic attraction, they are deposited on both horizontal planes and on walls or ceilings,
  • coagulation kinetics makes a very large concentration of nanoparticles unlikely.