WCing in my chemistry lab
 

One of my colleagues (a physicist) had a rather interesting research problem that required using a relatively high power TEC. He asked me if I had ever heard of peliters :)

Anyway, I am flying down to Chicago for a couple days to do some preliminary experiments at Argonne National Lab, and so I setup the Maze 3-1 today. I happened to notice that the bolts that hold the copper top down stick out into the base of the block. So it is not possible to use a 50mmx50mm TEC, as the bolts interfere. No worries, I just used some washers I had lying around the house.

http://www.procooling.com/~phaestus/solution.jpg

This may have been an isolated incident from getting a poly block with a copper top instead, or it could be a common issue. You could also solve it with shorter bolts. I am also using a 169W TEC (12V and 18A) and a Tt 420W PSU to push it (that's all I have around the house).

Here is the obligatory pic with frost:

http://www.procooling.com/~phaestus/cold.jpg

So I'll see you guys Thursday night after some cool (arrgh a pun) science is done.

Well I am burning the last of the data to dvd (filled up four dvd-rs) and thought I would post a picture of the actual setup. Here is the DD wb and cold plate mounted on standoffs upside down and with swagelock style fittings. This setup worked perfectly, and I am really excited about how well the experiments worked out. Be back home tomorrow...

so...errr...what exactly ARE you doing?

Yeah!, come on Hp, don't be shy! :D ...

That looks like some precision equiptment, something I always like to see. I love good engineering :) ...

The experiment was done at the Advanced Photon Source, the synchrotron at Argonne National Lab in Chicago. What was being done was 3d x-ray microtomography. Below the waterblock assembly are very precise motors that are computer controlled. One of the motors rotates the sample 180 degrees in very small increments (0.25 degree). The other motors are used prior to the experiment to adjust the sample so that it is in the exact center of the frame of view over all angles.

Behind the sample is a camera with CCD that takes an etremely high resolution 13,000 picture of the x-ray absorbance of a sample. These images are collected for every angle from 0 to 180, and the x-ray absorbance over all angles is used to reconstruct a 3d image of what is inside the sample. This is similar to a CAT scan at the doctor, but at a much smaller scale and at a much higher resolution.

Very computational intensive to convert the data. Pretty amazing technique. Once it is complete, you get images of slices of the inside of your sample. In the old days, this info would come from making tons of thin sections of sample with a knife and resins and then analyzing them with electron microscopy. This is a non-destructive alternative.

The peltier was needed to freeze water inside of a soil sample. The small aggregate was first analyzed dry, then after satuation with water, and then after freezing. How these conditions change the porosity and average pore size will be modelled once I get the software all in place. Currently, the chemical transport guys use empirical equations that could use a bit of revision.

Not all of it went over my head, but I do find myself wondering what the point is. So maybe it did go over my head. :shrug:

and here I was thinking "that's facinating, wish I had a job like that"

well, . . . .
- if I wanted a job

Pretty sweet setup pH. I still think you should get that 64CPU Xeon to crunch your numbers ;).

The pay isn't so great, but I enjoy going to work every day.

No job would still be preferable, but not yet possible for me :)

I would opine that you have resources there that as an individual you'd be hard-pressed to match
etc. etc.

one needs also to distinguish between 'want' and 'need'
ah so

to improve farming techniques or landscaping

Just a question....

how does a pelt improve agriculture?

You guys are pretty wide of the mark. Here's the justification:

You can think of soils as a huge buffer that acts as a barrier between the many things we apply to it on the surface and the groundwater below. Water flow through soils is how contaminants move from point a to point b. Big field scale models incorporate fairly complex equations describing the physical transport of contaminants along with water. These equations have input parameters that are all empirical. With the above experiments we are able to directly measure things like pore size distribution, porosity, pore connectivity, and tortuosity that have always before been estimated (or more commonly fitted). This is a big deal for those researchers studying transport through porous media. The peltier was used to subject the soil particles to freezing and thawing in succession to see how that might change the pore structure of the aggregates. This was all preliminary data collection; much more interesting stuff is being done now.

Not everyone doing research in colleges of agriculture is a farmer, btw.

cristoff, did you read what the experiment was? the TEC was used to cool down a sample that was scanned.

pHaestus, cool stuff, groundwater is just as important of an issue as anything else. i thought of fertilizers as soon as i read your explanation, that's why i said farming. anyway, any results yet?

Heh.... there's some issues with the program pH is using to analyze the samples. It wouldn't take his datafiles without a conversion to a different type, despite my attempts (and the program author's attempts) to rewrite the code. I don't think pH has gotten around to converting the data yet ;).

I have new code now though KE from a ph.d student at Arizona State. It "should" work like a charm. It's fortran based and we know the fortran compiler in gcc is working now. Going to give it a try Tuesday afternoon I think.

Like, code for 3DMA to read the NetCDF files you have? Cool.