Our take...

In an article which appeared in the August 20th edition of Science Punkt at al. make the case that corrosion is not an equilibrium process: it's best thought of as a phase change. To put this into everyday experiences...

Water changes phase (from liquid to gas) at 100 degrees C (assuming atmospheric pressure). What's interesting about that phase change (and even more so for phase changes of other substances - water is unique for all sorts of reasons not worth getting into at the moment) is that at these temperatures and pressures small changes in the environment can cause large changes in the macroscopic properties of the system. For example, small changes in the pressure in a vat of nearly boiling water can cause most of the water to boil off (more or less the idea behind a pressure cooker).

So phase changes are interesting in general, then, because they're times when small changes in the environment can lead to big changes in materials properties. If you want to design, e.g. concrete which cracks less readily in cold, plastics which are easier to shape or, as it turns out, steel which better resists rust, you need to understand what's happening at the relevant phase change and how to design your system to either inhibit or encourage change (depending on the specifics).

But back to corrosion. Prior work has demonstrated that viritually all metals form a protective oxide film when exposed to atmospheric conditions (because of reactions with water). Corrosion happens when holes are made through that film which rapidly grow and extend, downwards, into the underlying metal. Prior work has also demonstrated that under 'normal' conditions this protective film has small metastable pits. These pits typically appear and vanish on fairly small time scales, usually showing up at defects in the underlying crystal structure of the metal. Punkt et al. image metal surfaces under small changes in environmental conditions (small changes in temperature/salt content in the overlying water) and find that corrosion occurs when a critical density of the metastable pits occur: when the ms pits are close enough to feel each other. The observed sensitivity of corrosion to environmental conditions, and the pattern which corrosion follows once it starts can all be predicted (at least qualitatively) by a simple model of the process.

Why is this important you might now ask? If you're interested in a car which doesn't rust as easily or any other sort of metal part which works better when exposed to the environment, this knowledge is key. Now you know that one of the ways to beat corrosion is work really, really, hard at making your product defect free (so the ms pits occurs much further apart in the first place).

Unfortunately accessint the article requires a subscription to Science. For those so inclined the full reference is...

Punckt et al., Sudden Onset of Pitting Corrosion on Stainless Steel as a Critical Phenomenon, Science 2004 305: 1133-1136

Two of the groups involved in the research do have easily accessible web pages at which you can find out more about the sort of stuff they study:

-> Hudson Group at UVA
-> Mikhailov Group at the Fritz-Haber Institute

Yesterday a deranged (my purely subjective jusdgement), defrocked Irish priest (Cornelius Horan) tackled the leader in the men's marathon, the Brazilian Vanderlei de Lima, with about three miles left in the race. De Lima fell, appeared to be injured, but got up and continued the race, finishing in third.

In light of the Paul Hamm huballo (i.e. those who say he won the medal on a mathematical error so should give it back (ignoring what seems to be the current conventional wisdom that if the whole South Korean routine was reviewed he would do worse)) it seems reasonable to ask whether the Italian who won the race (Stefano Baldini) should give his gold to de Lima.

I've argued below that I think, more or less, that Hamm has every right to hold onto his gold. Evaluating what happened in the marathon seems both harder and easier. Harder in the sense that no one will really ever know whether de Lima wasn't almost all spend (i.e. whether the other runners were about to put on a late burst to bring themselves back into contention). Easier in the sense that Horan's actions clearly tilted the playing field away from de Lima. Would you really want to recieve a medal which, mostly, might come from your principal rival being attacked. I think I can say with some certainty that I would not (for more on the story see this news item. Kieren Healy's also posted on the nutty Irish guy here)

1. "Those Chinese are off the hook!" - beginnings of a discussion between two middle aged women while leaving the movie Hero.

2. "What's the best nation in the world?

What?

"Donation"

....

"Spare a dollar man. Come on, you don't have to be a Rockefella to help a fella."

-The last two in a sequence of ten jokes told by a homeless man looking for some help.

3. "Can I smell your feet?" - question addressed to me by a man who looked like a contractor/painter driving a minivan in the early afternoon in South Philadelphia.

So I read with interest yesterday that the International Gymnastics Federation has publicly requested (but will not force) American gymnast Paul Hamm to give the gold he won in this years all around competition in Athens to the South KoreanYang Tae-young.

The back story here, for the perhaps two people who might care about the forward story (on which I'm about to comment) but don't know the background is that after Hamm won the gold the FIG (yes Federation International Gymnastique) reqviewed tape of Young's parallel bar routine and determined that his start value (the degree of difficulty for his routine) had been miscalculated by judges and that he was owed ~0.1 points (enough to move him from bronze to gold.

Let's ignore all the practical objections to this review: 1. by rule it should have happened at the event (the South Koreans say they were told to file a protext afterward by a functionary on the scene but, if so, this was clearly against the written rule. 2. Hamm points out that if you do review the start value you should review the entire routine, in which case Young loses more than he gains.

Instead I want to just focus on the fact that FIG publicly requested Hamm give up his medal. How truly, truly ridiculous is this? FIG is the governing body of a sport. It has no buiness publicly requesting anything!!!!! Sport's governing bodies make their ruling (there either was or wasn't a violation) and then they move on. Can you imagine the NFL hierarchy saying to Terrel Owens last year "We're not going to fine you for the Sharpie signing end zone celebration (there was no rule violation on your part) but we're really uncomfortable with it and, when we think about it, we think there probably should have been a rule so if you could just please publicly apologize that would make us really happy." Absolutely not. And if they tried anything of the sort they'd be villified 24 hours a day across the US (yes actually 24 hours a day I'm imagining this decision as sports talk radio fodder).

So Paul, if you're reading this (you know unlikely but just possible) keep your medal. You won it fair and square, by the rules of the competition in place at the time. Your performance was bold and inventive - you're a champion in my book.

UPDATE: A number of people have pointed out to me that, while it's seems clear that the FIG is acting badly, the question surrounding whether Hamm should give up his metal is, perhaps, a bit more complicated. I should note, along these lines then, that my understanding of gymnastics judging (something of which I have no first hand experience) is that you can change your routine on the fly. Which is to say that, if Hamm had known he needed a different amount of points to win (i.e. if Young had protested and his score had been changed during the competition) he could have changed his intended routine to one that was higher risk/higher reward.

Ever since ESPN (no you will not get a link from me) moved the baseball columnist Rob Neyer into its premium section I've soured on them. While souring I've also required a new place to look for that sort of analysis coupled with a knack for clear and thoughtful writing.

Such a place is the weblog Red Bird Nation. This is a web log produced by a St. Louis Cardinal's fan so it mostly deals, naturally, with Cardinal related issues (hence the name). I've never been a Cardinal's fan but the guy who writes most of the entries is really more of a fan of baseball than of the Cardinals and his stuff is so consistently interesting and well written that it's a pleasure to read.

The recent theft of Edvard Munch's "The Scream" by a gang of masked thieves at gunpoint during business hours from it's museum resting place was, I thought, an aberration (I had - as I imagined most had - always thought of art theft largely as a business most often conducted in the dark of night). In a recent article in Slate Marc Spiegler makes the case that the times are a changing (with respect to art theft): that the Munch theft was emblematic of a new movement in the art theft world towards armed, conducted during working hours, heists. He argues (although I suppose it would actually be difficult to produce any empirical data on this point) that better security measures during nonworking hours (e.g. extensive networks of motion/body heat detectors) have led theives to work during more risky daylight hours where they can actually be reasonably sure they can get the work.

If you're interested in reform of the intelligence business (either because that's just the sort of person you are, or because you worry about national security issues, or because you're generally interested in the policy process - whatever the reason really) the Council of Foreign Relations has a nice summary of the various proposals currently floating around.

The interaction of microorganisms with their environment is critical to much of how we live: this interaction is the determining factor in much disease, it plays a significant role in the stability (or lack thereof) of the climate system and often determines such things as the cleanliness of our groundwater. For many years much of the interaction of microorganisms with their environment has been assumed to be largely chemical and largely atomic. For example the uptake of nutrients and the evacuation of cellular wastes happens usually because of some type of diffision, i.e. the process is explicable purely by paying attention to the relevant molecules.

Andrew E. Pelling, Sadaf Sehati, Edith B. Gralla, Joan S. Valentine, and James K. Gimzewski, in a just published paper in the journal Science, have found that the cell walls of live yeast cells vibrate with a characteristic frequency which is dependent on temperature. They argue that these oscillations are likely driven the the passage of groups of motor proteins on the inner side of the cell wall - something like the vibration of a house's wall as a nearby frieght train roles past (as Gimzewski explains on his web site). For the technically inclined, I should note that Pelling performed the observations using an AFM (atomic force microscope - essentially a molecularly small record needle) and live cells caught in the pores of a polycarbonate filter).

While the actual observation is interesting, even more interesting are the consequences. Pelling et al. seem to make the case the in the paper (and Gimzewski makes the case in other articles about the research) that it is likely that the observed oscillations are somehow passive: that they are diagnostic of healthy cell function. But it's clear from the paper that the oscillations take a lot of energy. It seems at least possible to me that, if the oscillations truly served no useful purpose (for the cell) the energy used to create them would have long ago been channelled elsewhere more effectively.

If the oscillations actually serve a purpose, it's not at all clear what that might be. More work is needed with tools which say something about the chemistry happening at the same time as these observed mechanical changes and that can resolve the dynamics of these chemical changes.

So there's still a long way to go, but if this oscillatory behaviour turns out to be spread widely among microorganisms, and if it turns out to be useful (to the cell) Pelling et al. have opened the door to an interesting new world.

The reference for the paper (only accessible over the web if you have a subscription to Science) is,

Pelling et al., Local Nanomechanical Motion of the Cell Wall of Saccharomyces cerevisiae, Science 2004 305: 1147-1150

However, if you'd like a reprint and don't have a subscription you can drop Gimzewski a line and ask him for one here.

From Sunday 8/22 through Thursday 8/26 the American Chemical Society will be holding it's biannual national meeting in Philadelphia. This is a usually a fun meeting (if you're interested in chemistry of any sort). Should you be interested in learning more about what's going on the meeting site is here. Should you be interested in the pure joys of chemistry - you know, molecules for the sake of molecules - also check out ACS's 'Molecule of the Week' feature here. Should you really, really, really, be desperate I'll be giving a talk on Thursday afternoon describing my attempts to create better living through nonlinear optics (better living in this case just means novel tools for probing the surface chemistry of colloidal particles in solution).

Because I have several good friends who work in the legal arena in Philadelphia I read with some interest this recent piece in Law.com. The gist of the article is that, yes, Philadelphia corporate lawyers do get paid less than those in other major metropolitan areas. Ignored in this analysis is that the cost of living (principally here I'm thinking of real estate) is also less in Philadelphia than in many other major cities. In other words, don't weap for the counselors from Philadelphia just yet (via Brian Leiter).

Using wind to generate electrical power is relatively common. Many states boast companies responsible for some small percentage of the total power that generate using wind (check out the American Wind Energy Association for more details). But wind, by itself, can never be the whole answer in power generation. Climatological factors play too critical a role: some states just aren't windy enough.

Where wind is inadequate it may prove possible to generate power by harnessing other natural processes: e.g. tides. In a small pilot project the energy company Verdant Power plans to install a series of turbines on the bottom of the Hudson river (next to New York City) which will rotate to follow the tides. Many practical issues still remain to be considered: e.g. the influence of fields of river bottom turbines on wild life, how to help the turbines spin freely in the presence of lots of debris, but wouldn't it be something, wouldn't it be really something, if someday New York got much of it's power from the tides?

My apologies for light posting over the last 8 weeks or so. I've been working in Beijing at the Molecular Reaction Dynamics Laboratory in the Institute of Chemistry for that period and web access to blogger (or to web logs in general) was erratic. I've got a number of rough drafts of interesting science related posts and more general notes about living and working in China which should appear within the next several weeks.