Maybe we're not talking about the same kind of container? We never had any kind of particles** in ours and with the use of a lid the ice does not appear for quite some time. We did not see 'vigorous boiling' either. If one leaves LN2 in the open it would eventually ice up regardless of the nature of storage container :-)
Artem * calling foam LN2 container a 'Dewar' is a misnomer, James Dewar would not be happy. ** there is a scenario in which particulates may form - and that is if a wet container (i.e. not dried for long enough after previous use) is subjected to LN2. This would rapidly freeze the water inside the foam layer and bust up the pores, resulting in particulates. _____ From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On Behalf Of Van Den Berg, Bert Sent: Thursday, October 09, 2008 11:03 AM To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] foam dewar usage ? Funny indeed. Our experience has been as well that icing of the foam dewars seems to be reduced compared to the "classical" ones. Bert -----Original Message----- From: CCP4 bulletin board on behalf of Schubert, Carsten [PRDUS] Sent: Thu 10/9/2008 9:15 AM To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] foam dewar usage ? Hmmm, that's funny. Our experience was quite the opposite. The first time we used one of the darker small dewars we ended up with a lot of burr in the LN2. Those got picked up by the cryo and we ended up with lilac particles embedded inside the cryo. You can imagine the reaction when these particles showed up in the mounting camera .... We also noticed that the LN2 in these dewars actually ices up more rapidly as compared to the glass dewars. We attribute this to the lower insulating capacity of the foam dewars, which causes a vigorous boiling action and the higher turbulence seems to suck in more ambient air. Needless to say the dewars did not make it past the first use... Carsten -----Original Message----- From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] Behalf Of [EMAIL PROTECTED] Sent: Thursday, October 09, 2008 8:50 AM To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] foam dewar usage ? Yes, we use them all the time and they're great. Stuff does not slip on the bottom like it does in the glass Dewars and the formation of ice is greatly reduced. Plus, they're much easier to dry. Artem > Does anyone in the biocrystallogaphy community use foam dewars for > handly liquid nitrogen and freezing/manipulating frozen protein > crystals ?
