Hi George,
That one is a new one for me.
I would not go as far as calling them "SCA's (Spherical Crack Arrestors),
more like "SCRs" (Spherical Crack Retarders) or "LSCRs" (Local Spherical Crack
Retarders). After all, the cracks propagation is only slowed down, and then only
where the void is not in the rest of the SJ volume. Chuck Schmidt at SRI had
some pics showing just that, but i never got a copy of thos pictures.



Werner

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