Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Structure formation by nanosilica particles suspended in levitated
  droplet   Vaporization of liquid droplets containing particles has been studied
extensively for its applications in combustion, thermal coating, ink-jet
printing, spray cooling, drug delivery, and surface patterning. Droplets
containing solid particles show a preferential solute-migration during drying
process. Recently we carried out experiments with vaporizing droplet suspended
in an acoustic levitator. In this work, we present detailed study of a laser
irradiated droplet containing nanosilica particles. Infrared and High speed
imaging of the heating process for different concentrations of nanosilica
revealed an interesting solute migration pattern. Further investigation with
Particle Image Velocimetry shows presence of strong recirculation within the
levitated droplet. It also reveals that with increasing viscosity of the liquid
the strength of this recirculation decreases. Due to the droplets rotation
about the levitator axis, a centrifugal force also dominated the flow field
within the droplet. High speed imaging shows that initial stage of heating is
dominated by sharper diameter reduction. At the end of this stage the droplet
takes a bowl shape. Next stage, which is termed as structure formation shows
different characteristics for higher and lower concentrations. For nanosilica
concentration of less than 1.3%, the bowl shape remains unaltered with further
heating. On the other hand, for concentration greater than 1.9%, due to
stronger centrifugal effect than recirculation, the particles migrate towards
the equator plane creating horizontal ring structure. The horizontal ring very
soon starts oscillating about the levitator axis. This creates an imbalance of
forces resulting in reorientation of the ring. Thus a vertical ring is created.

18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th