End of Week 1

Week 1 of the summer research institute has come and gone. At the end of this first week we seem to have a pretty good grasp on the running of the falling head test along with how altering the different parameters effects the resulting k value.  Today we decided to switch things up by adding some marbles into the sand to act like rocks. We started with just a few marbles layered on the sand topped with an additional layer of sand and worked our way up to over 50 marbles. The falling head test was run just as before by placing the smaller tube into the sand and filling it with water and timing how long it takes the water to fall a certain distance. The addition of the marbles took longer for the to fall making our calculated k value smaller as expected.

We also started to look and try to comprehend the Matlab code that we will actually be using to produce and image with our data. The code is much different than what we were using before to practice and seems to be a little confusing at the moment, but I am confident that we will be able to get in figured out in the next five weeks.

Next week we will begin our exploration into the constant head test, starting with the construction of the required apparatus. We can't fully start the exploration until we obtain a new glass cylinder. The glass cylinder that was being used became the first casualty of our research, shattering while Matt attempted to remove the sand and marbles. Next week we will probably head over to Duck Creek to do some preliminary research into the sand/soil composition, seeing if the sand/soil will even allow us to take measurements and maybe get some tests done to see what potential problems we might come across. 

Column with marbles (picture added by Susa)

More testing, more data

Another day of testing of the F-60 sand and more of the parameters have been acquired. We figured out that the reason for the differences in the k-values from the previous day was because the sand in the inner column was higher than the sand around the inner column. We tested this and found that by adding more sand into the inner column it changed the k-value. From now on we will figure out our length by how much of the inner column is in the sand by using the inside amount. This change helped us to get more accurate k-values. We then moved on and started running a few tests with the F-65 sand. This sand is consider to be more fine which will mean there will be less room for the water to move through. Due to this, we are predicting that the k-values will be lower than that of the F-60. So far in the few tests we have ran, the data looks that way. Whether there will be a statistical significance is yet to be determined!

Yesterday we had consistent results until we stirred up the sand and reinserted the column of sediment.  Then the K value dropped, we hypothesized that this might be due to settling of the sand.  We tried leaving it set-up and then this morning we tried it again, but the faster K values remained....  We're now hypothesizing that the system is very sensitive to sand levels inside and outside of the column (supposed to be the same, but don't seem to end up that way.)  We're trying it again with different levels of sand inside the tube, which we think is the more important value and hope that using the inner sand level will stabilize values...

The many uses of MATLAB

As we begin our research with experiments in the lab, we are also learning a whole new language on the computer. Learning the MATLAB language is a slow process, but one that should yield some useful computer simulations to compare with experiments done in the lab. To learn this coding language we jumped right in and attempted to reproduce diagrams using the code and a lot of trial and error. We started with some simple figures to reproduce and every time we would load the next image we had to reproduce we were sure we couldn't do it. Eventually though we would manage to get something right on the figure and everything else would start falling in place.

After reproducing one of the many figures I couldn't help but see the potential in the shape that I had produced. The shape was a solid rectangle with a triangle on top, and in my mind I couldn't stop myself from seeing a house. Feeling confident enough in my ability to use what little I had learned of this coding language I made it my mission to turn this figure into a full out piece of art using the MATLAB coding language.

I started with simply making a region of the diagram display as green while some displayed blue. In this I had created a lawn to accompany the house and sky. I couldn't stop there though, I then continued to code in a chimney to sit atop the roof of my house. With help from my other group members we developed a design for the front of the house and in time created a door and windows to brighten up the house. After taking a moment to admire the structure we all decided that the sky seemed very empty and that the sun would have to be created. Learning how to create circles along the way and determining how to most effectively use the code, a sun and bright rays of light were placed upon the figure.

While learning and taking command of MATLAB I managed to produce a solid piece of art. This is only the start to what I'm sure we will all learn is one of the many uses of MATLAB.

Today we started doing falling-head tests.  We began with "play sand" as the cheapest and easily replaced sand, but this was an absolute disaster.  We don't know why the water wouldn't flow through the play sand, but it simply stopped.  It also dirtied the water, so we have a hypothesis that it has a significant amount of fine particles, that are clogging the tube... This was unexpected and quite worrisome at the time.  The complete halt in the falling water remains a mystery, but unknowns are what make it research, right?

Jessica, David, and Matt collect falling head hydraulic conductivity data.

       We then switched to the sand from Ottawa, IL (F-60?)  These runs worked much better.  Students are currently investigating the effect of the vertical location of the column (How close to the bottom can it be?  How far into the sand does it need to be?)  The intent is to figure out some general guidelines on column placement to be used later in more heterogeneous conditions.  We also want to find out now if there are general set-up changes that we should make to get consistent results before the system gets more complicated.  We should find out more tomorrow...

Yesterday (6/25/12) started off the program.  In the morning we discussed logistics and played an icebreaker game with the entire group of summer students.  In the afternoon we broke into our respective research groups and discussed the scope of our project and then started learning Matlab.  I was very impressed with the students' progress in understanding for-loops, if-statements, and managing to modify some Matlab codes to plot matrices that would create specific images.

Welcome...

If you are reading this, you are probably a summer research student, who has been requested to blog here, a friend or family member of said student interested in what we are doing, or you have perhaps mistakenly been directed here by some obscure google query.  In any case, enjoy!

The purpose of this blog is to help us (me and my summer research students from St. Ambrose University) stay organized and informed of our progress during the summer program.  We will be investigating the falling and constant head tests used to measure hydraulic conductivity in streams, through field, laboratory, and computational experimentation.