
Math Problems This project requires XAD columns for filtering water samples and PUF (polyurethane foam) plugs for filtering air samples while we are in Antarctica. The XAD columns and the PUF plugs will be taken back to Virginia to be analyzed for POPs. Click here for a special printable version of this page. Problem One: We need lots of PUF (polyurethane foam) plugs for our experiments that analyze and measure POPs in air samples. Each sampling process needs 2 PUF plugs. We will do two sampling processes each day. We need enough PUF plugs for 42 days worth of work. How many PUF plugs need to be cleaned? Problem Two: Use the total number of PUF plugs you calculated in Problem Two: We also need 12 PUF plug "field blanks". We have 15 PUF plugs already cleaned. We have seven weeks to clean the PUF plugs clean and get them ready to be shipped out. How many PUF plugs need to be cleaned each week? Problem Three: It takes three days to clean a PUF plug. How many should be started every three days in order to have them ready in time? (To make this problem easier, assume that a week has six days, even though people work every day in order to get ready for field work.) Problem Four: 60 XAD columns are needed altogether for water samples 10 are ready now We have seven weeks to clean the columns and get them ready to be shipped out. How many XAD columns remain to be cleaned each week? Look at this image of Michele’s lab sheet. It gives you the answers for problems 1, 2, and 4. Problem Five: Note: a "filtering thimble" is the name for each piece of equipment that is used to clean an amount of XAD. The image to the right is a filtering thimble.
When we started preparations, we needed 60 clean XAD columns. We are using the Soxhlet lab filtering thimbles to wash the XAD before it is packed into columns. To fill each column, it takes 1 1/2 small filtering thimbles. How many small filtering thimbles will it take to clean and pack 60 XAD columns? Below is an image of some small setups. Problem Six: We can use some large Soxhlet lab filtering thimbles to clean the XAD. You can pack 1 1/3 columns with each large Soxhlet filtering thimble. How many large Soxhlet lab filtering thimbles will it take to clean and pack 60 XAD columns? Here you can see Amy with some large filtering thimbles. Problem Seven: There are three parts to this problem. Refer to the "recipe" for cleaning XAD material in the Soxhlet apparatus. How many days does it take to clean and wash the material in a Soxlet lab filtering thimble? Look back at your answer for problem five. If we can process 8 small s filtering thimbles at one time, how long will it take us to clean the number of filtering thimbles you calculated in problem five? Look back at your answer for problem six. If we can process 6 large filtering thimbles at one time, how long will it take us to clean the number of filtering thimbles you calculated in problem six?
