Dear Mark,

        The magnetic force is proportional to the volume (L^3) of the particle
and the drag force is proportional to the cross-section (L^2). When we
reduce the particle diameter the magnetic force drops faster than the
drag force. So the speed of a smaller particle should be less than a
speed of a larger particle.

        The simulation results support this explanation. I attach pdf files
with data for trajectory calculation and here is the summary:

Drag force tissue/saline ratio k=1000.
Small 15nm-particle traveled the distance 0.375 m in 1115 seconds (it
was 473 seconds for the large 100-nm particle - see results calculated
on May, 2)


Drag force tissue/saline ratio k=1.
Small 15nm-particle traveled the distance 0.375 m in 35 seconds (it was
14 seconds for the large 100-nm particle - see results calculated on
April, 24)



        Time spent 1 hour.




Best regards,
         Alex

-------------------------------------
Aleksandr Liubimtcev
QuickField Support team
http://quickfield.com
e-mail: aleksandr.liubimtcev@quickfield.com




On 05.05.2019 17:18, Mark Arokiaraj wrote:
> Dear Alex,
>
>             The last result can you perform with the particle size of
> 15nm instead of 100nm and without the same drag force 1 and 1000. This
> will highlight the results of smaller particles.
>
> with regards,
> Mark