[Homeroast] Poisson's ratio WAS: Re: Compak vs Macap vs Rocky Grinders

Robert Yoder robotyonder at hotmail.com
Tue May 18 16:39:54 CDT 2010


One man's Mean is another man's Poisson!

 

Happy Roasting,

 

robert yoder
 
> From: koenig.mike at gmail.com
> Date: Tue, 18 May 2010 10:34:03 -0400
> To: homeroast at lists.sweetmariascoffee.com
> Subject: Re: [Homeroast] Poisson's ratio WAS: Re: Compak vs Macap vs Rocky Grinders
> 
> I'm probably splitting hairs here, but Poisson's effect happens on the
> molecular level, with bonds elongating under pressure or strain. I'm not a
> geoscience guy, but I imagine the effect effect would happen in rocks, dense
> clays and shale, etc, but what you are seeing in a coffee puck is
> interactions between discrete non-uniform particles.
> 
> I'm not arguing at all that you don't get some lateral expansion during
> tamping, since that certainly does happen, but it's not necessarily uniform,
> and dependent on the distribution (and re-arrangement under force) of the
> particles, as opposed to poisson's effect, which describes a predictable
> amount of lateral expansion based on the change axial length. If the
> expansion was due to poisson's effect, the puck would spring back when you
> let go of the tamper. What you are getting is some re-arrangement of the
> particles under force (like when you step in sand, and it moves out of the
> way under your foot).
> 
> --mike
> 
> 
> 
> On Tue, May 18, 2010 at 3:01 AM, <raymanowen at gmail.com> wrote:
> 
> > Then I don't know why the grounds would press out and seal against the
> > sides
> > of the basket when you are only applying axial force with the tamper.
> > Hydrostatic?
> >
> > I hope I don't owe a refund of all our pay at the Geophysics Research
> > Institute at CSM. Please don't tell Dr. Levent Ozdemir or Dr. Russ Miller
> > we
> > were doing bad oil shale research. Damn!
> >
> > What supports you when you walk on a sandy beach?
> >
> > Teach me, please. -ro
> > _______________________________________________
> > Homeroast mailing list
> > Homeroast at host.sweetmariascoffee.com
> >
> > http://host.sweetmariascoffee.com/mailman/listinfo/homeroast_lists.sweetmariascoffee.com
> > Homeroast community pictures -upload yours!) :
> > http://www.sweetmariascoffee.com/gallery/main.php?g2_itemId=7820
> >
> _______________________________________________
> Homeroast mailing list
> Homeroast at host.sweetmariascoffee.com
> http://host.sweetmariascoffee.com/mailman/listinfo/homeroast_lists.sweetmariascoffee.com
> Homeroast community pictures -upload yours!) : http://www.sweetmariascoffee.com/gallery/main.php?g2_itemId=7820
 		 	   		  
_________________________________________________________________
Hotmail has tools for the New Busy. Search, chat and e-mail from your inbox.
http://www.windowslive.com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_1


More information about the Homeroast mailing list