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More replies to Yavari, fractals, strongly emotional disputes, and what really leads to Nobel prize

Dear Yavari

I have promised more replies on Mandelbrot, fractals, strongly emotive discussions in journals, and here is a coincise statement, which I take from a Nobel prize, prematurely passed away last year.  I think it has a lot to teach (including the kind of attitude that leads to Nobel prize, i.e. close to no human weakness), you will recognize the real name of the "Caesar" in this book is somebody with a 58 pages CV on his web site, most likely.

For a better idea of fractals, read please the other attachment.

Regards

Mike

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are there platforms similar to iMechanica? should we list them all?

I think it would be useful to collect a list of most useful sites, to start with iMechanica-look-alike.  Not exactly similar but a good site for CFD is http://www.cfd-online.com/.  This incidentally suggests us some "ways" to improve iMechanica.  (see my other blog PROPOSAL for iMechanica node/2996)

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a review of a paper by HD Bui found in the internet !!

dear iMechanica friends

I came across a review of a paper by HD Bui who was somewhere in the internet, and I find it is very interesting. I could even have written this review myself !!  I don't think the reviewer exaggerates....

michele

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Rail corrugation: ”one hundred years of solitude”? or a true enigma?

You may remember that I promised some time ago to discuss each of the topics mentioned by Ken Johnson in his Timoshenko Medal speach. Here I take rail corrugation. Rail corrugation has been noticed at least for 100 years, but (particularly short pitch one in the range 20÷80 mm) has been considered an enigma because measured corrugation wavelength did not relate well with wear instabilitymodels.

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PROPOSALS FOR IMECHANICA

Hello imechanica users: I launch a few ideas. Can we improve imechanica stealing ideas from successful web systems like google, amazon, wikipedia, myspace, youtube? Taking the best of the various worlds to improve our imechanica?

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Italian stress analysis AIAS conference in Ischia --- call for papers Sept.

dear Imechanica users,

a wonderful location for our annual italian conference in stress analysis -- see www.aias2007.it. It is organized by our collegues in Università di Napoli, Prof. Renato Esposito. Attached the call for papers in PDF, and more info are below.

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Does anyone know a collection of Lennard Jones potential material constants??

I am trying to find out the theoretical adhesive strength limit of a few materials, or more precisely the ratio adhesive strength limit to elastic modulus. I think this is after all part of the Lennard-Jones constants potential - theoretical adhesive strength limit is simply the maximum of the curve.

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Contact mechanics of rough surfaces: is Persson's theory better than Greenwood & Willamson?

A recent string of papers originated from Persson's paper in the physics literature contain a number of interesting new ideas, but compare, of the many theories for randomly rough surfaces, only Persson's and Bush et al, BGT. These papers often assume the original Greenwood and Williamson (GW) theory [1] to be inaccurate, but unfortunately do not test it, assuming BGT to be its better version. The original GW however is, I will show below, still the best paper and method today (not surprisingly, as not many papers have the level of 1300 citations), containing generally less assumptions than any other model, including the constitutive equation which does not need to be elastic! I just submitted this Letter to the Editor: On "Contact mechanics of real vs. randomly rough surfaces: A Green's function molecular dynamics study" by C. Campaña and M. H. Müser, EPL, 77 (2007) 38005. C. Campaña and M. H. Müser also make several questionable statements, including a dubious interpretation of their own results, and do not even cite the original GW paper; hence, we find useful to make some comments.

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Some notes on Luan and Robbin's papers on contact and adhesion at atomic scale

As I promised, I start with some brief notes on themes loved by Ken Johnson to hopefully raise some interest for discussion on iMechanica. Regards, Mike

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