iMechanica - friction - Comments

maybe the theory is not crazy after all .... if only:

Mike Ciavarella — Thu, 03 Apr 2008 06:05:50 -0400

If only we consider that the basic mechanism for bubble formation is compression of thin layers, which clearly in rubber and with no asperity makes the slow Schallamach "waves" (or better, fronts) that we have been able to see already with technology of the 1960's. But there is no reason not to admit bubbles can also be generated within asperities of micron scale, at nanometer scale, so that we cannot see them.... Yet! But together, we see their movement. I wish de Gennes were alive, I was supposed to meet him last year in Trieste at a workshop, I cannot tell you how disappointed I was not to have had the chance to meet with him. Now, I could have stepped into his office in Paris and he would have confirmed or disprooved my theory in less than a second.

So this seems to be one case where, as Michel de Montaigne says, "I only took other people's flowers, and all I did was to find the chord to bind them"! So here the idea may not be that crazy, just the natural step forward on the shoulders of giants like Bowden, Tabor, Johnson and ... especially de Gennes!

mciava@lms.polytechnique.fr

Aplied Mechanics in offshore industry

ausberto — Sun, 30 Mar 2008 18:02:44 -0400

Hi Professors and scientist, I am a Master student in Brazil , I am new member in mechanica comunity

actually I research in viscoplastic behavior of polimers aplied to subsea pipelines

if anyone share information in this area, I will be deep gratefully

ATE

Ausberto

course materials

fsyedrizwan — Sat, 29 Mar 2008 21:32:36 -0400

hello sir i need the course materials for mechanical engineers

help

ouzeriat.a — Wed, 28 Nov 2007 05:22:22 -0500

please how to begin on that problem contact with friction (what the books) for will understand the phenomene

contact with friction and fatigue

ouzeriat.a — Mon, 26 Nov 2007 05:48:11 -0500

modelisation of contact two bodies with friction

Replies to energy dissipation by electronic excitation

Xiaoyan Li — Mon, 05 Mar 2007 08:26:22 -0500

Thank you very much for your interest in our studies.
The friction at the nanoscale is controlled by two mechanisms: the electronic and phonon dissipations. Since to date, it is not clear which contribution of the phonons and electros to friction is dominant. Some researchers concluded that electronic and phonon dissipation channels are of similar importance for the microscopic origin of friction.
In our present investigation, we performed the classical molecular dynamics simulations which are unable to describe electronic motion and electronic structure in the bearings. Therefore, the contribution of phonon to friction is only studied, and the electron contribution is not considered.

energy dissipation by electronic excitation

Henry Tan — Mon, 05 Mar 2007 00:36:57 -0500

In the end of the paper it is written that for a molecular bearing at the atomic scale, the phononic excitation is a main energy dissipation mechanism.

Why the energy dissipation caused by the electronic excitation is not important?

what makes journal different: standards for publication

Henry Tan — Fri, 09 Feb 2007 00:17:14 -0500

Good journals set a high standard for publication. Papers in poor journals usually contain lots of errors, and hard to trust the reported results.

On journal suggestion; labels and the flat internet

Pradeep Sharma — Thu, 08 Feb 2007 22:06:41 -0500

I am perhaps going to take this discussion even further away from what Mike presumably intended in his initial post (----on that by the way, Mike, I would not suggest submitting your manuscript to a "plasticity" journal. This opinion is based on the type and topics of papers I see that appear in say Int J Plasticity. In my subjective opinion, JAM and the like are good bets for your topic).

Zhigang, on a philosphical level I agree with most of the points you have brought up however there are some practical concerns which the younger faculty members or researchers cannot ignore. For an established researcher it is indeed true that there is little difference in the "label" he/she chooses. As you pointed out, internet is flat; all journals are accessible electronically and if the work is good everyone will seek it out....etc. etc. However, early career researchers, if in an academic institute, have to go through the requisite tenure process and eventually other promotions. While I certainly don't endorse this practice, most administrators/bean counters DO judge the quality of the work by the "label" i.e. the name and reputation of the journal or (sometimes to my vexation) by its impact factor. I suspect, although am not sure, grant review panels also pigeon-hole researchers according to the perceived quality of the journals the prospective grantee publish's in.

Regarding "superficial discussions"....I am puzzled as well...the ability to chat with fellow mechanicians across the world (on both pointless and weighty matters) is (as the master card ad claims) "priceless"! (:-)

On lables and other superficial topics

Zhigang Suo — Thu, 08 Feb 2007 21:19:20 -0500

The difference between JMPS, IJSS, MOM, JAM, say, is analogous to the difference between a Coke can and a Pepsi can: They are containers of different labels but with similar contents.

The difference between JMPS and Journal of Hepatology is analogous to the difference between a Coke can and a Miller Light can: They are similar containers with different contents.

Even in a flat world of journals, with equal accessibility of (nearly) all papers, labels (the names of the journals, the names of the authors, the keywords, etc.) still serve useful purposes, as indicators of likely contents, and as brand names.

But when you have doubt if you prefer a Coke or a Pepsi, perhaps you might as well stop agonizing and just think the difference between the two labels make no difference to you.

Your conclusion that "the Internet, forums, chatting, are all about superficial discussions" puzzles me. Which part of this thread of discussion leads you to this conclusion?

To me, such discussions simply complement discussions in a hallway when we cannot be together in person, and complement formal articles when we don't feel like to be formal. There are times and places for formal, long discourse. There are times and places for informal, to-the-point (or pointless) chats.

Isn't it wonderful we can choose whichever mode of communication, or none at all, that pleases us?

If the World is flat, what makes journals different?

Mike Ciavarella — Thu, 08 Feb 2007 17:28:40 -0500

I still find myself reading JMPS more than Journal of Hepatology, or Annals of Physics!

But of course a careful answer to my question requires attentive readings at least of the abstract.

Perhaps we are leading towards the conclusion that internet, forums, chatting, are all about superficial discussions?

p.s. I still thank you for your comments, nobody else of course has done better!

Regards, Mike

Reply from Bob McMeeking, the Editor of JAM

Zhigang Suo — Thu, 08 Feb 2007 16:13:13 -0500

Bob McMeeking sent me this message and asked me to post it here. ZS

Zhigang, I will have to consult ASME on this before I can give you an answer. As you know, ASME is transitioning to online-first publication and from then on papers will have doi numbers, and the on-line version will be considered to be the primary vehicle for the Journal. Publication dates will then be determined by when the on-line version is released, as with many other journals now. The plan I think is to do this by 2008. I assume that ASME will establish its policies on pre- and post-publication posting on the internet clearly in the context of its new online-first publishing system. In the meantime, I will look into what our policy sould be until the online-first system is operating.

I only regret that ASME is only now proceeding with its online-first publication system and that it won't be functional until the 2008 volume appears. However, as you know, ASME has gone through a reorganization and rationalization which has only now given them the capital to invest in the new system.

With best regards

Bob McMeeking

The World is Flat

Zhigang Suo — Thu, 08 Feb 2007 15:58:52 -0500

Dear Mike:

In my initial reply, I did give my reply to your question. Perhaps not quite the answer you wanted to hear. To me, it makes little difference which journal one submits a paper to.

All papers are accessed from the Internet. The World is Flat, to borrow the title of Tom Friedman's book. The Internet is even flater. All papers are a few clicks away, regardless which journal you publish in.

Zhigang, you have taken

Mike Ciavarella — Thu, 08 Feb 2007 10:42:15 -0500

Zhigang, you have taken quite a different path than the original question --- where should I publish a paper such as that described? Independently on putting it into Imechanica or not, now you ruined my question and probably nobody will ever answer that.

This, incidentally, is a risk of the "forums", instability with respect to initial intentions!

Most journals in mechanics allow authors to archive preprints

Zhigang Suo — Thu, 08 Feb 2007 08:10:59 -0500

Dear Jim: As far as I can tell, most journals in mechanics allow authors to archive both pre-refereeing copies and post-refereeing copies. For example, all Elsevier journals (except for Cell Press) allow authors to do both. This will cover us for JMPS, IJSS, MOM, and many other popular journals in mechanics and materials.

The web site I gave the other day is very easy to use to check the standing of any particular journal. The site shows that journals like Applied Physics Letters and Journal of Applied Physics and all Physical Review Journals allow authors to do both.

Interestingly, the ASME Journal of Applied Mechanics is unclear about these permisions. I'm forwarding this discussion to Bob McMeeking, the Editor of JAM, so that he can clarify the issue.