In sci.physics, Archimedes Plutonium

wrote
on Fri, 27 Aug 2004 01:45:21 -0500
:
Tonight I need to clean up a few items on the backburner of research. A
good science mind has not just one or two or three projects of interest
but more than 50 going all at once. If memory serves me it was Autumn of
2003 when I asked for a physics answer as to how long it would take for
a 4 foot high steel drum 3 foot wide full of wet sand to dry out inside
a building. I do remember one gentleman replying that it would rust out
the drum which gave me some concern for I do not want it to rust out.

Is this a sealed drum? If so, the only way to remove the water is for
it to react with the insides of the drum. Even with an open drum the
water has to get to the surface, convert to vapor (evaporate), and
blow away.

Of course iron rusts fairly readily, though I don't know the precise
mechanism offhand (the chemical reaction is typically represented
as Fe + O = Fe2O3 [ferric oxide] but I suspect it's more complicated
than that, involving such things as electron migration).


And a few weeks ago I emptied the steel drum and I found out this since
it was stored for approx 1 year in that 2/3 way down the sand was dry
but the last 1/3 distance was still wet sand.

A) So what I am thinking is that the measure of 1/3 wet sand is a
measure of the moisture in the air. And that the steel drum is like some
huge measuring instrument itself. And that the air is never really dry
and thus the sand in the drum will always have a fraction that is wet.

B) An alternative answer is that the 1/3 sand that was wet is due to the
inability of air to flow down that depth and that given more time in
storage it may have dried to 3/4 and then 4/5 etc etc.

Air doesn't flow too well through solid sand. :-) Of course, water
is known to wick up through narrow channels -- I'm not entirely
clear as to why, although the effect is well-known; most likely
it has to do with adhesion and/or surface tension.


But I do not have the time to check out whether A or B is the better
answer.

There was some rust on the bottom and a couple of years ago (do not
remember the exact date) I discovered that tar not only hinders rusting
of steel but actually dissolves rust from steel and returns the surface
to pure steel. Armed with that knowledge I now scrape off, wirebrush and
sometimes sand rusty surfaces and then apply a coat of tar; let dry and
then apply paint over the top of the tar. And some future date if it
peels I peel it off and find pure steel metal underneath to re-tar.

I could see tar preventing water from contacting the iron and
thereby preventing rust -- mostly because dry iron can't rust,
presumably (no path for electron and/or ion migration). Then
again, I'm not all that up on my inorganic chemistry.


Archimedes Plutonium
www.archimedesplutonium.com
www.iw.net/~a_plutonium
whole entire Universe is just one big atom where dots
of the electron-dot-cloud are galaxies



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