The Design Process

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For the environmental concerns, since our system hopes to eliminate plastic and reduce the negative impact of non-renewable sources of energy, our system needed to be energy efficient, and circular in that the expenditure of energy used to maintain the system was less than the energy produced to create a positive impact on the environment. Although such environmental concerns are of utmost importance, in the designing process of the hardware we sought to temporarily exclude the energy component of our designs (while still being mindful) to focus on the more unique hardware components.

For the safety concerns, because we are working with e.coli the entry system (where the plastic would be placed) needed to be sealed off from where the bacteria culture. Thus we embarked upon the long process of “figuring out how to put something into the culture without being exposed to the culture”, while keeping a sterile environment. Thus we started to look at a double compartment system with a heated middle that sterilized the components, this is a hardware piece that we explored more at the end of the designing process.

Now with this in mind we again relooked at the larger goal, we embarked upon research on how to filter out such ethanol, where we encountered several filtration methods but the energy expenditure of such was too high, therefore we decided upon utilizing a millipore filter. Noting that the size of E.coli is between 1.0-2.0 micrometers long and Ethanol of 0.44 nm. The utilization of such filters would allow for a non-energy consumption way to filter out ethanol while keeping the e.coli in its LB broth. Furthermore we then saw how polar molecules, such as some of the LB could also run through the filter therefore in testing our hardware we should consider the effects of such in the quality of fuel source created.

After we designed some of the first sketches of our hardware, however, in doing research we saw how density could affect our design, as the original filtration system considered the ethanol to go down in LB. Furthermore we run some testing in the lab with different LB mediums and ethanol, experimenting with different proportions of LB and water to see if it would alter how the ethanol moved; the result of such experiments was that different LB consistencies did not alter the movement of the ethanol, as it always rose to the top. In doing so we altered our design and looked for a more creative solution to filtering out ethanol that rose to the top while keeping the LB culture in the main compartment and avoiding the disruption of it.

Lastly we worked to continuously improve our design, by including important sensors and redesigning the structure to be as efficient as possible.

After we created the first 3d model of our design and 3d printed the first prototype where we tested some of the basic tubing and saw if LB still was able to move through it, which it was.

After that we started to work with a product designer, Ikharo Yunus, to start improving the visual of our prototype and thus produced the final 3d model.

Some considerations of the final 3d model: The hardware is seen as independent of the entry system where the PET plastic goes in, as well as independent of where the ethanol byproduct is stored and further distributed The technological parts, such as control boards are oversimplified, however PH sensors, Temperature sensors, and the rotating tool are still included in the hardware design.

For further steps, using this 3d model we want to replicate it using specific materials that comply with the constraints of our project specifically sterilization wise. Such materials include surgical aluminum and materials which can sustain cold weather conditions, where in the next few weeks we will continue to apply our initial hardware design the to the conditions it would be subjected to in its natural environment and modifying in the process in hopes of created a better designing and building a real life version of it.