Along with our mentor and advisor, Scott and I decided that this will be our last week of experiments, due to having already collected such large amounts of interpretable data.

We will run a last experimental series on a column with organic material, and then we will focus on writing our paper and organizing our poster. I also have to write my abstract early, because I want to attend GSA (who else is going?!).

Column with organic material that we had to dismantle, due to the material being too hydrophobic.

Como Conservatory and Zoo on Sunday.

Greetings fellow REU students!

Monday evening I received a text from Teri asking me if I wanted to go with her to a Hmong market in St. Paul, which she had already been to in the weekend. It was almost 5 pm, and I said, “Sure! as long as we are back by 7:30 pm.”, to which she replied: “I’m sure we’ll be back by then”.

When we left the dorms, we got slightly lost getting to the light rail, as we were trying to use a shortcut. It also had started to drizzle slightly, but we though it wouldn’t rain much.

Half an hour later, we get to our stop in St. Paul, and the rain has started to intensify. We asked each other if we wanted to go back, but not wanting to seem weak or unadventurous to one another, we decided to run in the rain to the market. After walking/sprinting for less than one block, we were soaking wet. The rain came down much more heavily, and combined with the wind, it looked like we were in the middle of a storm. After finding shelter in a small supermarket for about 10 min. we decided to run to the nearest Chinese restaurant we could find.

As we partially dried, while eating and drinking tea, we saw reports on the TV about extreme flooding in Minnesota. By the time we finished eating, it was a beautiful cloudless and sunny day.

We proceded to find the market, which turned out to be closing. After walking through the few stalls left, we decided: “We’re here, why not visit the cathedral?!”.

Which tuned out to be closed too.

We ended up returning to the dorms at 9:30 am, two hours later than planned, but I am glad to have shared this small St. Paul adventure with Teri.

Large rabbit sculpture we found walking through St. Paul.

The calm after the storm in St. Paul.

This week, Scott and I have been analyzing the results from our experiments. We have been able to complete our experiment five times successfully, now we are seeing the results and what they mean, and then we will change our experimental setup to see how results change. I am happy to have a much better grasp of our research and what it means, thanks to the analysis we have done. Here is a graph showing the saltwater concentrations we measured after adding the saltwater to our column, and then after 2 or 3 rinses with clean water. Drain, the blue section of each column, shows the saltwater concentration of the saltwater filtered through the column, which is diluted a bit by the clean water that might have still have been in the column from previous rinses. Then, the column is rinsed twice with fresh water, until the saltwater concentration is less than 1% of the one originally added. As  mentioned, we conducted five successful experiments, because we are discarding Cycle 1 and Cycle 3. Cycle 1 was our first, so the sediment inside the column was dry, making the results unrepresentative of what happens when we pour saltwater through sediment that already contains some clean water. For Cycle 3, we forgot to measure conductivity of the Drain, so we barely have any data on it.

I am excited to see how our research keeps evolving!

-Francesca

Today, Teri, Jabari, Scott, and I attended a tour of MTS Systems Corporation. Graduate students from civil engineering and students from the NEES REU also took the tour with us. The MTS employees who gave us the tour were very welcoming and enthusiastic when answering our questions. They showed us how some of their fatigue test systems and motion simulators work. Being a geology student, I was very interested in a rock mechanics machine that would use stress to identify rocks by their resistance.

They may not know how to spell my name, but the people at MTS were extremely helpful and pleasant. 

Francesca Toledo Cossu

Today, Teri, Jabari, Scott, and I attended a tour of MTS Systems Corporation. Graduate students from civil engineering and students from the NEES REU also took the tour with us. The MTS employees who gave us the tour were very welcoming and enthusiastic when answering our questions. They showed us how some of their fatigue test systems and motion simulators work. Being a geology student, I was very interested in a rock mechanics machine that would use stress to identify rocks by their resistance.