Week 6

Week 6

As we began collecting data on the leaking rate of the plastic tube as well, we have begun preliminary testing of  the critical pressure. We finished constructing the experimental setup and tried varying internal pressures to see if the setup worked.

Critical Pressure Threshold Experimentation

We finally finished fabricating the experimental setup for the critical pressure testing. This is how the experimental setup looked like:

Experimental Setup for Critical Pressure Experimentation

The protocol simulates how the capillary tube will pierce the tube with reagent in it. First, we will the tube with 'reagent'. In this case, we used water, as shown:

VacuStor Tube with Mock Reagent (Water)

Then, we fit it onto the rubber stopper, which has a half-drilled hole to place the tube in. Then, we attach the vacuum tube to the tube and evacuate the tube at the desired pressure we want. We can evacuate the tube to varying extents to create differing levels of internal vacuum. Finally, we cap the tube, and then remove the tube out of the setup. Then, we fill the capillary with fluid, and then pierce the tube with the capillary. Depending on the pressure, we can get no sample transfer, partial sample transfer, or full sample transfer. Since we wanted to make sure this setup worked, we chose pressures that we knew the outcome would be, and here were the results:

Left tube was tube with high vacuum; Right tube was tube with low vacuum

As you can see, one had no sample transfer, and one did. We weighed the tubes before adding the water, after adding the water, and after the sample transfer, and used the density of liquid in order to determine how much sample transfer there was.