1) Project Identity
Design of Magnetic Field Concentrators
Week 4 Report
Due: Sunday February 27th
Group D: Mohammedjuned Desai, Areio Hashemi, Koji Hirota, Michael Wong
2) Work Completed
The eighth week was a slow week for us as we ran into a couple of setbacks. Our magnet core (Mu Metal) had just arrived and was about begin our fabrication of the final product. However, the company that we originally found (near Fullerton, CA) that does sells magnet coils does not actually do coiling. The customer service of that company was very poor so we had to result back to looking for other companies. We found 2 more companies, one near Rancho Cucamonga, CA and one near Los Angeles, CA. The one near Rancho Cucamonga also does not do any coiling of magnets itself and notified us that they only sell them. We are currently in contact with the company near Los Angeles and communicating through email and found out that they do coiling but we must first finalize the software analysis so we can give them the dimensions. However since the contact process might take more time than originally planned, we decided to create our own magnets for testing and familiarization of the calibration process until our true design is complete. We have set up another meeting with Dr. Rodgers group to learn coiling of the magnet. However this solution also produces a problem. We need the magnets to be identical or else they would produce a different force and if we put them together on the setup the force would not be uniform. A solution was proposed for this problem even if the magnets are not the same we could use different currents to power the magnets which could then cause both of the magnets to generate the same force and hence we could use it to produce our setup. For this process we have bought a metal steel rod of diameter ¼ inch, a plastic tube with internal diameter of ¼ inch. The metal steel rod is the core substitute for the Mu metal and the plastic tube is for coiling process. We still need to decide on the gauge of the wire to use for coiling and we will get it by next week. On the other hand this week we were able to finalize our software design and we no longer have to use FEMM to run anymore models. This week we change the location of the coils on the magnet to see how that affects the magnetic field gradient. We did this because the coils were in the way of the sample and to move the coil a away from the tip it will allow our magnet to get closer to the sample below are some of the sample results of what we obtained this week.
From doing these finalized runs we found that the distance of the coils between the ends of the magnets does effect the magnetic field and so does the number of coils. The larger number of coils the more field strength we get and the further the distance from the end of the magnet the less field strength we did. So from these results we have concluded that we have to move the coil further away from the end and compensate the power loss by adding more coils to the magnet.
3) Future Work
For the upcoming weeks we will have to fabricate the design of the magnetic tweezers. We will continue to keep in contact with the coiling companies and see what the final answer and their pricing of the process. We also will need to get in contact with the machine shop as we need to modify the core to the appropriate size in addition we will be meeting up with Dr. Rodgers group to learn how to coil the core of the magnets. However, our fabrication does not have to be limited by the coiling of the cores. Next week we can still attempt to begin our fabrication by setting up the other parts of the tweezers, including the placement of different equipments such as the microscope, the cameras, stage and aluminum block to hold the magnets. Since we have bought some parts for the magnets we can begin to build our substitute magnet after we buy our copper wires for the coiling process.
4) Project Review
This week in general was a started off a disappointing week. Our coiling companies that we originally thought that could coil the magnets for us do not actually do any coiling of the magnets however, we were lucky enough to find another one and this company is in Ventura, CA and they do coiling of magnets once we can provide them the specific dimensions. We have not actually begun the fabrication of the magnetic tweezers design and as a result this will set our schedule back. On the other hand we did manage or complete all of the software analysis which is a relief as we can finally begin to fabricate our product without the worries of having to build a wrong design. Here is the progress chart as of week 8.
1st Quarter / Goal / CompletedWeek 1 / Determine goal and objectives for the project / X
Week 2 / Finalize the proposal / X
Week 3 / Learn how to use FEMM, building models, producing results etc. / X
Week 4 / Begin running magnet models / X
Week 5 / Begin discussing and analyzing results / X
Week 6 / Complete all the software models and analyzing the results / X
Week 7 / Start ordering/gathering parts to begin fabrication / X
Week 8 / Begin fabrication
Week 9 / Attach the part to the microscope
Week 10 / Have prototype/design already built
2nd Quarter
Week 1 / Read up and familiarize ourselves with protocol on the calibration of the magnetic tweezers
Week 2 / Being calibration
Week 3 / Proper Placement of Mirrors/Objectives
Week 4 / Finding Linear Region of the gradient field
Week 5 / Focusing Camera for Viewing Bead Movement
Week 6 / Calculating Velocity of Beads from Measured Distance and Time and use Stokes Equation to fine the Force Exerted on the
Week 7 / Begin experimentation
Week 8 / Take data from sample
Week 9 / Compare data with published results
Week 10 / Finalization of the product and calibration