Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Experiment and Modeling of Rice Winnowing: Granular Segregation Method
  in Ancient Traditions   Rice winnowing is a process of separation of small and large rice grains by
air flow practiced since the ancient human history especially in societies
where rice is the main source of carbohydrate (in Asia, Africa, and Latin
America). Indeed, this process contains rich of scientific rule but has never
been documented by the old society. We report here experimental investigation
of the rice winnowing and develop a physical model to explain the process of
segregation of rice grains having different size or density. Flapping the tray
in the winnowing process, generates a vortex centered at position around the
tray free end. We demonstrated numerically that the effectiveness of
segregation is strongly depended on the different in grain sizes (for grain
from the same material), the initial position of the grain, and the angular
velocity of the vortex generated by flapping the tray. We obtained a phase
diagram describing different final conditions of winnowing process (either the
small grains move towards the tray fee end or move toward the inner end of the
tray, able or unable to leave the tray at the free end). The result can be
useful to design a new method in separating grains based on size or density.

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The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
21
The categories of this paper are: adap-org
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The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio