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Shape--both spheroids and irregular, larger particles with
small spheroids attached.
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Distribution of radioactivity--some particles radioactive
throughout, some particles radioactive only on or near the
surface.
These properties indicate that after the liquid particles
solidify, they begin to agglomerate with the irregularly shaped dust
particles and with each other.
The daughters of the nuclides in the
gas phase are continually being deposited on the surface of al]
particles until the particles fall out of the gas cloud.
The
refractory elements in a given fallout sample are acquired partially by
agglomeration, but the volatile elements all are acquired by
condensation on a solid surface.
The spheroidal particles in a sample
should show a strong inverse relation between r(A) and particle size.
On the other hand, the irregular particles in a sample, having been
sieved, contain variable (indeterminate) relative amounts of solid
particles and gaseous condensate.
Therefore, in a sample containing
both spheroidal and sieved irregular particles, the relation of r(A) to
particle size will depend on the relative amounts of spheroidal and
irreqular particles in the sample.
The inverse relation of r(A) and particle size is easily seen in
the Smoky data.
There is less of a trend in the Shasta data and still
Jess in the Diablo data.