[RASMB] SedVel60K centerpieces [was Cell Leak]

[Virgil Schirf]

We haven't used the the SedVel60K centerpieces here, but I've also heard 
anecdotally about the problem you describe. Using aluminum and titanium 
centerpieces which require gaskets is more cumbersome (and expensive!) 
than using the SedVel60K centerpiece, but if optical artifacts are 
indeed a problem then using the higher speed rated centerpieces or 
taking a chance with the epon-charcoal centerpiece is the only way to go.

Virgil

John Philo wrote:

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>Virgil and the group,
>
>What is your experience using the 60K epon centerpieces from UNH for
>absorbance? I have heard that there are problems with optical artifacts,
>presumably due to the light hitting the sides of the narrow channels. Has
>anyone looked at this carefully?
>
>John 
>
>-----Original Message-----
>From: rasmb-admin at server1.bbri.org [mailto:rasmb-admin at server1.bbri.org] On
>Behalf Of Virgil Schirf
>Sent: Wednesday, August 24, 2005 11:46 AM
>To: Allen H Pekar
>Cc: rasmb at server1.bbri.org
>Subject: Re: [RASMB] Cell Leak
>
>
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>The older archived RASMB emails can be found at:
>http://rasmb-email.bbri.org/rasmb_archives
>and current archives at http://rasmb-email.bbri.org/pipermail/rasmb/
>Search All the Archives at: http://rasmb-email.bbri.org/rasmb_search.html
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>
>Allen,
>
>We've seen the rib break but not bend as you describe. The centerpiece 
>is probably now corrupted especially for speeds that far above its 
>maximum rating. I would worry that if any resulting surface 
>irregularities developed during bending, eddying effects may occur even 
>if the centerpiece remained intact. Empirically, you might be able to 
>check the integrity of the centerpiece by running something like BSA and 
>critically examining the data.
>
>You might want to consider purchasing centerpieces that are rated for 
>use up to 60krpm such as titanium, aluminum, or the SedVel60k graphite 
>filled epoxy centerpieces.
>
>Best regards,
>
>Virgil
>
>Allen H Pekar wrote:
>
>  
>
>>RASMB members:  We had a cell leak today where all the liquid leaked
>>from one sector but little leaked from the other sector.  As a result 
>>of spinning at 60,000rpm, the plastic between the two sectors was 
>>bent.  When the cell was taken apart, the plastic returned to its 
>>original shape.  Has anyone had this happen and if so, is it safe to 
>>use the centerpiece?  We mostly do velocity runs at 60,000rpm. 
>> Thanks,  Allen Pekar (Eli Lilly and Company) 
>>    
>>
>
>
>  
>

-- 

Virgil Schirf
CAUMA & CLS
Department of Biochemistry, Rm 4.523U
The University of Texas Health Science Center
7703 Floyd Curl Dr.
San Antonio TX 78229-3900 Voicemail: 210 567-6590
Fax: 210 567-6595
Email: schirfv at biochem.uthscsa.edu