[lit-ideas] Re: For Those Who Were Worried...
- From: Julie Krueger <juliereneb@xxxxxxxxx>
- To: lit-ideas@xxxxxxxxxxxxx
- Date: Tue, 14 Feb 2012 11:59:31 -0600
And yet a five year old can do it.
Julie Krueger
On Tue, Feb 14, 2012 at 2:47 AM, <cblists@xxxxxxxx> wrote:
>
> On 14-Feb-12, at 6:00 AM, David Ritchie wrote:
>
> ...the ponytail problem has been solved:
>>
>> http://www.bbc.co.uk/news/**science-environment-17012795<http://www.bbc.co.uk/news/science-environment-17012795>
>>
>
> "'It's a remarkably simple equation,' explained Prof Raymond Goldstein ..."
>
> I was wondering just how 'simple' so I searched - and found
>
> The Shape of a Ponytail and the Statistical Physics of Hair Fiber Bundles
> - Raymond E. Goldstein, Patrick B. Warren, and Robin C. Ball
>
> [Abstract] A general continuum theory for the distribution of hairs in a
> bundle is developed, treating individual fibers as elastic filaments with
> random intrinsic curvatures. Applying this formalism to the iconic problem
> of the ponytail, the combined effects of bending elasticity, gravity, and
> orientational disorder are recast as a differential equation for the
> envelope of the bundle, in which the compressibility enters through an
> ‘equation of state’. From this, we identify the balance of forces in
> various regions of the ponytail, extract a remarkably simple equation of
> state from laboratory measurements of human ponytails, and relate the
> pressure to the measured random curvatures of individual hairs.
>
> http://www.damtp.cam.ac.uk/**user/gold/pdfs/ponytail.pdf<http://www.damtp.cam.ac.uk/user/gold/pdfs/ponytail.pdf>
>
> It is reported at the end of the paper that the work "was supported in
> part by the Schlumberger Chair Fund."
>
> Chris Bruce,
> wondering (after perusing Goldstein, Warren and Ball's paper)
> a) about the definition of the term 'remarkably simple' as used there,
> b) just who it is (outside of the Steven Seagal fan club, perhaps)
> who finds the problem of the ponytail 'iconic', and
> c) if I'd find a Schlumberger Chair down at the local hair salon, in
> Kiel, Germany ------------------------------**
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