[Avodah] Making Ice Cream on Shabbat

[Prof. Aryeh A. Frimer]

Has anyone seen a Halakhic discussion about making Ice cream on Shabbat. 
There is something known as an ice Cream ball 
[http://icecreamrevolution.com/; video: 
http://www.youtube.com/watch?v=z4t3SWKYWCE&NR=1].  In one compartment you 
add ice and rock salt; in the other you add sugar, cream, and vanilla.  Then 
you shake for about 10 minutes and the mix freezes during the agitation to 
give a pint of ice cream.
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Dr. Aryeh A. Frimer
Chemistry Dept., Bar-Ilan University
Ramat Gan 52900, ISRAEL
E-mail: FrimeA at mail.biu.ac.il