[RASMB] SedVel60K centerpieces [was Cell Leak]

[John Philo]

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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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

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