[ExI] Help with freezing phenomenon

[spike]

>...A very short (and potentially very 'dirty') description of the
process: a valuable bluefin tuna is caught and put in the CAS freezer on the
boat...--that the ice is in the form of small granules that substantially
reduces freeze damage...Does this mean that given similar geometry, water
will cool more slowly than ice?... Best jeff davis  


Jeff, this is interesting but your explanation may be wandering off in the
wrong direction.  Do indulge me for a minute please.

Water expands as it freezes.  In a conventional freezer the outer layers
freeze first, so as the internal layers freeze and expand, the outer layers
are placed in tension and are filled with tiny cracks.  We might suppose the
presence of microcracks in fish could degrade its sushiability. 

If one uses a microwave oven, one may observe that the food cooks from the
inside out, as opposed to the convection oven where it is reversed.  

In the process you describe, I can imagine a system whereby the center of
the tissue (a fish or a valuable brain for instance) is kept artificially
warm by very low level microwaves while the entire mass is very gradually
cooled to just slightly below freezing.  Then a second synchronized and 180
degrees out of phase microwave source could be injected from the other
direction.  At the center of the fish or valuable brain, destructive
interference cancels the microwaves starting at the center.  Then the center
freezes first and slowly, as thepower of the  pi-phase-synchronized
microwave sources are gradually decreased.  

That way, the center freezes first.  The frozen portion then expands
slightly against a still unfrozen outer portion, which eventually freezes
solid without the microcracking, maintaining the sushiability of the meat.
Preserved could also perhaps be valuable knowledge, if we are talking about
a brain with something actually in it.

We could experiment with this theory by scavenging a couple of magnetrons
from two identical junky old microwave ovens.  I know how to synchronize
them and control their power.  So we could see if we could take a bowl of
water with these magnetrons on either side and freeze it in such a way that
it is perfectly clear as opposed to milky white with jillions of cracks.
This would be like an icicle which freezes from inside out, as opposed to a
usual bowl of water in the freezer, which freezes on top first then freezes
inward.

Perhaps Max's staff might want to join our efforts in finding a better way
to preserve sushi and valuable brains.

spike