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Mike Ciavarella's blog

electroadhesion of rough surfaces, with application to touch screen technology

Submitted by Mike Ciavarella on

Just submitted a paper on electroadhesion of rough surfaces, greatly simplifying the recent theory of the great Bo Persson , with hot application to touch screens :  see here

Comments welcome.

The false myth of the rise in Italian self-citations, and the impressively positive effect of bibliometric evaluations on the increase of the impact of Italian research

Submitted by Mike Ciavarella on

Title: The false myth of the rise in self-citations, and the impressively positive effect of bibliometric evaluations on the increase of the impact of Italian research

Authors: Pietro D'Antuono and Michele Ciavarella

Categories: physics.soc-ph math.ST stat.TH   Comments: 20 pages, 8 figures, 10 tables, in English and inItalian  License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/

 https://arxiv.org/abs/1910.02948

Mean stress effect on Gaßner curves interpreted as shifted Wöhler curves

Submitted by Mike Ciavarella on

A criterion for the mean stress effect correction in the shift factor approach for variable amplitude life prediction is presented for both smooth and notched specimens. The criterion is applied to the simple idea proposed by the authors in a previous note that Gaßner curves can be interpreted as shifted Wöhler curves. The mean stress correction used has been proposed by Smith, Watson and Topper and, more in general, by Walker.

On the top 100 000 scientists in the world / the most authoritative and impressive ranking available today

Submitted by Mike Ciavarella on

See this impressive ranking of the top 100 000 scientists in the world.

 

Somebody told me about it as I appear as the best of my University, Politecnico di Bari in Italy.

https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3…

 

 

Universal features in "stickiness" criteria for soft adhesion with rough surfaces

Submitted by Mike Ciavarella on

A very interesting recent paper by Dalvi et al. has demonstrated convincingly with adhesion experiments of a soft material with a hard rough material that the simple energy idea of Persson and Tosatti works reasonably well, namely the reduction in apparent work of adhesion is equal to the energy required to achieve conformal contact. We demonstrate here that, in terms of a stickiness criterion, this is extremely close to a criterion we derive from BAM (Bearing Area Model) of Ciavarella, and not very far from that of Violano et al.

A comment on "A dimensionless measure for adhesion and effects of the range of adhesion in contacts of nominally flat surfaces" by M. H. Muser

Submitted by Mike Ciavarella on

I attach a Letter I sent to the Editor of a tribology journal, concerning adhesion of rough surfaces. 

I contend that some "criteria" that have been proposed based on extrapolation of numerical results are due to the limitations in present numerical sophisticated rough contact simulations, which only span at most 3 orders of magnitude of wavelengths, so typically people simulate from nanometer to micrometer scale.