Oops- forgot Colin's paper. The references for this and the other paper are:
CJ Pennycuick and A Lock
Elastic energy storage in primary feather shafts
J. Exp. Biol. 1976 64: 677-689.
http://jeb.biologists.org/cgi/content/abstract/64/3/677 (abstract only)
R Bonser and P Purslow
The Young's modulus of feather keratin
J. Exp. Biol. 1995 198: 1029-1033.
http://jeb.biologists.org/cgi/reprint/198/4/1029.pdf (full-text PDF)
Rgds,
Richard
> -----Original Message-----
> From: Engineers and biologists mechanical design list
> [mailto:[log in to unmask]]On Behalf Of Julian Vincent
> Sent: 29 September 2003 12:11
> To: [log in to unmask]
> Subject: Re: Birds´ feathers
>
>
> Colin Penycuick did a paper many years ago in J Exp Biol looking at the
> bending of the tip of a birds feather and relating it to energy storage
> at the end of the wing stroke.
> But it's easy enough to set up the rachis as a cantilever beam and twang
> it to get a resonant vibration. Record with high-speed video (these
> days) or shine a light through a slit and have the rachis cast a shadow
> onto some photographic paper (a way I did this with grass yonks ago.
> Also described in the book on experimental techniques with biological
> materials - IRL press. Or do it on a strip of material in a torsional
> pendulum (again easy to set up) at a number of temperatures (-20 in a
> freezer to + 40 under a heat lamp would be quite possible.
>
> Ulrike Wegst wrote:
>
> > Dear All,
> >
> > Are you aware of measurements of the damping performance (mechanical
> > spektroscopy, loss coefficient ...) of bird´s feathers or beta-keratin?
> >
> > I am grateful for any references and help you might be able to provide.
> >
> > Looking forward to hearing from you.
> >
> > Kind regards,
> > Ulrike Wegst
> >
> >
> > Dr. Ulrike G.K. Wegst
> > Max-Planck-Institut für Metallforschung
> > Heisenbergstr. 3
> > D-70569 Stuttgart
> > Germany
> > Tel: +49(0)711-689-3423
> > Tel: +49(0)711-689-3412
> > Email: [log in to unmask]
> > e
>
> --
> Julian FV Vincent [log in to unmask]
> Professor of Biomimetics office 01225 386596
> Centre for Biomimetics & Natural Technologies mobile 07941 933901
> Dept of Mechanical Engineering fax 01225 386928
> The University
> BATH BA2 7AY
>
> http://www.bath.ac.uk/Departments/Eng/biomimetics/
>
> I hate quotations. Tell me what you know. (Ralph Waldo Emerson)
>
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