Sunday, September 5, 2010

A short course in Vienna

As I type (Saturday morning 4 Sept 2010) this I am sitting on a train, traveling from Vienna to Zurich, where I will change trains for my trip home from my latest adventures. The plan, when I scheduled the travel was to enjoy the mountain views out the window, but the clouds are low, so while I can tell that there are hills out there, I can’t tell if they rise up into mountains. However, as we passed Salzburg I did get glimpses of the peaks as the clouds parted, so the time spent on the train will have been worth it for that view, if no others come along. With luck I will get a chance to post this once I’m home, since I don’t expect to have any internet access at all next week.
After leaving Budapest and the IMA conference I traveled first to Salzburg, where I spent the weekend playing tourist and visiting the salt mine at Hallein (photos from that trip to follow in another post), and then doubled back to Vienna, where I attended a short-course on the Kinetics of Geologic Materials.
The course turned out to be as useful as I’d hoped. I signed up for it in large part because, having had such a long break between taking my last math course and enrolling in my PhD program, I’d found that when reading papers I had a tendency to skip over formulas and jump to the next descriptive part of the text. In an effort to overcome this habit I have checked out text books on the thermodynamics behind the chemical reactions which form minerals, and, to some extent, they helped. However, I still felt like I was missing something in my understanding of the math/formulas that one needs to describe what is happening during mineral-forming reactions, and so this course.
There were more than 25 of us who signed up for the course, traveling there from Italy, Germany, Hungary, the Czech Republic, and more. We range in experience from advance undergraduate geology students to post-doctoral researchers. At the end of our course we shared information on our current research in a poster session ( good percentage of us had attended the IMA conference in Budapest), and our specialties range from experimental studies to traditional petrology—from the crystallization of minerals from a melt, to zoning in metamorphic minerals and a number of points in between. One student is even studying the ability of rocks in Hungary to store man-made CO2.
The lectures started with an introduction to thermodynamics—the study of the relationship to the energy of a system to the equilibrium thereof. The common physical example used to illustrate this point is to stand a rectangular block on its narrow end. So long as it is on a flat surface and nothing happens to it, it will happily stand there all day. However, being taller than it is wide, should anything bump into it the block will fall over and land on its broad side. We describe the block standing on its narrow end as “metastable”, because if energy is added (it gets pushed), it will transform to its more stable state of lying on its broad side. Chemical reactions are much the same. Minerals are each stable in a specific range of conditions (pressure, temperature, and composition of the rock itself), but some chemical reactions take more of a “push” to make them happen than others. In these cases the minerals will often exist in conditions during which they are not expected to exist, in which case, like the block standing on its narrow side, they are metastable.
From this simple example the course built up the mathematical framework of how to describe the energy used to “push” the reactions into happening, and how to use published values for that energy to determine for any conditions what minerals will be expected to be stable in an equilibrium situation. We touched on many related topics related to kinetics, including diffusion (how the elements within the minerals move from one location to another so that the chemical reactions will happen), nucleation (the earliest stages of the growth of a new crystal), and the boundaries between grains and/or phases. For most topics presented we also had exercises to work on during the lab hours—using MATLAB to perform calculations on these processes for model (simplified) systems.
All in all the week was a very valuable experience, but train has reached an area where the mountains are visible, so it is time to shut down the computer and enjoy the view.

1 comment:

Roads said...

Ah, Vienna -- how wonderful. And I love Zurich, too.