Tuesday, December 24, 2013

The h index

I was explaining to a.colleague how to calculate.the h index of our department, since he got surprized that an emmeritus professor of our department (who does not publish too much) appears three times in the list of the 34 most quoted papers. I explained that this is a problem of the h index (if II remember well, Hirch pointed to this in his paper): it gives too much value to old published papers, which, due to their long lives, received lots of citations. Then I got the idea of using a time-dependent h index, let us say, based on the list of papers published in a given time span (for example, the last three years). This will give a best estimate of the citation strength os a set of researchers. Of course, this time-dependent h index may be artificially inflated by the own researcher citing his own papers, thefore I suggest introducing a secondary index, which I call the citation strengrh, which is the number of citations (full) divided by the citations excluding self-citations. In my opinipn this index computes the probability that an article published by that author is cited by someone else. I would like to hear your opinion about this idea.

Friday, December 13, 2013

Brilliant minds

We are still mourning the passing away from our friend Larry Kaufman. I was thinking about him today, thinking about how lucky I was to have the opportunity to know him in person and thought about other friends, some who already left us, and some who are still with us. I decided to choose three of them, to share with you some of my recollections of the interaction with these extraordinary persons. This is no biography, I just want to share few memories which are special to me.

The first one, of course, must be Larry (Lawrence) Kaufman. I first heard his name as co-autor (with Berstein) of a book called CALPHAD, which we (still) have in our library. I first met him in Erice, at the 1996 Calphad conference in Italy, He knew I worked in the MPI Eisenforschung so he called me aside, to show a calculation of Al-Ti-Fe phase diagram using his database (which uses only crude models, regular solutions, ideal solutions, line compounds), showing he could reproduce a particularly tricky phase equilibriium involving the t2 phase, my colleagues had experimentally determined. This was characteristic from him. It does not matter that he coined the term CALPHAD, that in some sense, he was a kind o "father" to us all, he was always available and interacting, even with the humblest of the graduate students (myself). It in not everyday that you have the opportunity to "chat" with the person who created an entire scientific discipline (computational thermodynamics) and a whole industry (e.g. Thermo-calc, Pandat and so on).

The second extraordinary person is John Cahn (to my best knowledge, still alive and well). I met him at many occasions, but I remind in particular, my visit to NIST in 2001 on the way to the CALPHAD in Boston. I was showing some results on modelling crystal defects in intermetallics and said that I was doing that for my "Livre-docência" thesis (some Brazilian copy of the German habilitation). He told me he, in his entire life, had written only one thesis, his Ph. D. . The implication was clear. If he, himself, needed only a title, why should anyone else have other titles? I realized this and quickly answered that by doing this, I would get a 30% raise in my salary and he replied then, therefore, that I should do it, laughing. John Cahn is well known, even to physicist, due to the Hilliard-Cahn equation and some consider that he is the closest materials science will ever get to a Nobel prize winner.

The third special person was Ryioichi Kikuchi. One of the most privileged minds I ever met, I consider him to be of the level of Einstein, Bohr, Heisenberg and Feynman. I was working at the MPI Eisenforschung in Düsseldorf and met this tiny japanese guy walking in the corridor. I knew already he was coming for a three months for the fourth round of the Alexander von Humbolt prize grant, so I guessed right. At that time I remember him telling me his first recollection of Brazil was about watching one of his relatives departing on a ship to a distant country which was painted in green at the Mapa Mundi he had in his fundamental school. I made that time the decision to invite him to visit Brazil, so he could have opportunity to visit this lost branch of his family, what we did in year 2000. Sadly he passed away 10 years ago, but his memory will stay with me forever.

Wednesday, December 11, 2013

Results of the triennial evaluation by CAPES

Our graduate program on Metallurgical and Materials Engineering was evaluated by CAPES in the last triennial evaluation with grade 7, the highest possible and the first in the whole history of Escola Politécnica da USP. Congratulations to Professors +Jorge Tenório , +Denise Espinosa , Sérgio Duarte Brandi and Francisco Rolando Valenzuela Diaz, who led us to this unprecedented good result.

Monday, December 9, 2013

The world of Martian rocks: a cutting-edge system to materials characterization.

Launched in 2012 by NASA the Curiosity robot has revealed a lot of secrets from the red planet only studying Mars rocks and soil geology. What is the mechanism that allows human robots perform the Mars remote sensing of small rocks in a research to seek water, life and the own Mars's history?

The human robot is a real high-technology interplanetary laboratory. It is the state-of-the-art of a magnificent engineering achievement. It is equipped with a high-power Laser in an ingenious multipurpose device named by project’s scientists as ChemCam (Chemical Camera). The high-power Laser emits a short pulse with a big power which is focused on the surface of some rocks samples. The high energy density on the surface rock or in a sample of sand may induce supersonic plasma emission: so then, this light is collected by a spectrometer and with this information, scientists can identify the spectroscopic lines of the chemical elements in the rocks! Scientific literature refers to this technique as Laser-Induced Breakdown Spectroscopy (LIBS).

Fig. 1: ChemCam Artist's Conception by NASA.

The Curiosity robot has many devices developed in several countries including Russia, Netherlands, Germany and United States. Since 2012 a lot of discovers were reported with ChemCam and another devices. For example the first ionizing radiation measures in the red planet, a dry riverbed in a Martian crater and the first drilling in a Mars's rock in seek of water.

The amazing discover was, no doubt, performed by the ChemCam and its high-power remote sensing instrumentation. The robot reports that Mars sands are enriched with nutrients essential to life occurrence like Oxigen, Sulfur, Nitrogen, Phosphorus and Carbon. It also reports clay in Mars that indicates there were long periods of aqueous soil in the red planet. The great question is: Would be Mars an environment able to hold life? Better than this: Was Mars a planet with an ancient civilization?

Matheus Tunes, 23, is Graduate Student Candidate at Polytechnic School of the University of São Paulo  
Scientific Website

Fig. 2: A typical LIBS spectrum. In this case, we generate plasma in a deionized water sample. Tunes, MA; Schön, CG et al. INAC 2013 Proceedings, ENAN X121 E06, p. 1-6 (2013) ABEN-RJ.

Long way to learn how to use internet

I finally discovered how to connect my blog to my google+ account, thanks to +Felipe Pait , who showed me this was possible.

Sunday, December 8, 2013

Two useful services

Recently I got in touch with two online services which I find most useful.
The first is the ResearcrhGate : at first sight a social network of scientists, is much more than that. It is a draft article repository and a place to post and answer technical questions which are visible worldwide. I guess it will change the way we do science, but maybe I'm exaggerating.
The second service is SciRev : have you ever had an unpleasant experience with a magazine? A manuscript which took too much to review, a badly written reviewer report? Some manuscript which was unfairly rejected? The place to post you complain is scirev. You may also access the service to see the stats of a particular magazine.
So, have fun!

Reinaugurating the blog

I was so busy in the last few years and left this blog unnattended. Now that my administrative duties diminished, I want to start posting again. It was never my intention to be the sole contributor. If you wish to post science and technology related topics here, please contact me. Depending on the case I may give you posting privileges. The only rule I wish to maintain is thst the posts and comment must be in english.