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Team:Cornell/notebook/drylab/week 2
From 2012.igem.org
Week 2
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Wednesday, June 13, 2012
Focus: System Flow Discrete versus continuous: debate on food and water delivery system continues. Details
Saturday, June 16, 2012
Focus: System Flow Decisions have been made! With flow method and battery selected, we move onto pumps. Details
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Wednesday, June 13, 2012
Today was a huge discussion day, in which we continued our previous discussion on fluid flow through the system. Last time, we leaned toward a discrete system because it would cut energy costs due to less activity. However, Dylan told us today that discrete flow would not work because the culture needs to maintain steady state. According to the equations and graphs he drew on the whiteboard, discrete flow would not satisfy this requirement. Any deviation from steady state would add noise to the electrical output from bacteria, rendering the biosensor inaccurate. Still, Maneesh and Dylan tried to design a discrete system that would work. A programmable fish food dispenser would periodically release food into the bioreactor that held the bacterial culture. And a microcontroller would be used to activate the water pump. However, the issue of maintaining steady state still lingered. On the whiteboard, we also came up with two other designs--a passive gravity fed system and a continuous model. For continuous flow, pumps would be constantly churning food and water into the bioreactor. The disadvantages are incredibly low flow rates (meaning higher-end machines) and greatest power consumption. In the passive system, food and water input from above the water level would flow down into the bioreactor. This design allowed for continuous flow and least energy consumption. However, the bulk of this system would need to be strictly underwater, so we would have to look into waterproofing. #filtration #flow #gravity
Saturday, June 16, 2012
Maneesh and Dylan made a presentation for discrete flow. The system seems to be complicated, as it involves pressure gradients and the use of feedback loops and modifiers to generate pressure equalization. Since simplicity is a top priority, we returned to continuous flow because it would be easier to implement and still fulfill the functional requirements. During further discussion, we did a back-of-the-envelope calculation for a continuous flow rate of water. It came out to be 0.03 milliliters per minute, which meant we needed a very precise, slow-acting pump. For the purpose of conserving energy, Dan found some low power pumps, including a $5 Chinese manufactured pump and a $20 500 GPH (gallons per hour) bilge pump. However, more research is required to find the optimal pump. We also thought about methods for introducing food into the stream. One idea was to use a worm-gear compressor to slowly push through our system. Chie presented candidates for our biosensor battery. We selected a 100Ah deep cycle gel cell battery, after listening to suggestions from several professors. Lydia and others discussed meeting with ECE professors to figure out the logistics of the circuitry component. We have a rough plan for developing the potentiostat, which is vital for measuring changes in potential, or signal produced by the bacteria when they detect toxins in the water. #flow #pump #battery #potentiostat
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Wednesday, June 13, 2012
Focus: System Flow Discrete versus continuous: debate on food and water delivery system continues.Entry:
Today was a huge discussion day, in which we continued our previous discussion on fluid flow through the system. Last time, we leaned toward a discrete system because it would cut energy costs due to less activity. However, Dylan told us today that discrete flow would not work because the culture needs to maintain steady state. According to the equations and graphs he drew on the whiteboard, discrete flow would not satisfy this requirement. Any deviation from steady state would add noise to the electrical output from bacteria, rendering the biosensor inaccurate. Still, Maneesh and Dylan tried to design a discrete system that would work. A programmable fish food dispenser would periodically release food into the bioreactor that held the bacterial culture. And a microcontroller would be used to activate the water pump. However, the issue of maintaining steady state still lingered. On the whiteboard, we also came up with two other designs--a passive gravity fed system and a continuous model. For continuous flow, pumps would be constantly churning food and water into the bioreactor. The disadvantages are incredibly low flow rates (meaning higher-end machines) and greatest power consumption. In the passive system, food and water input from above the water level would flow down into the bioreactor. This design allowed for continuous flow and least energy consumption. However, the bulk of this system would need to be strictly underwater, so we would have to look into waterproofing. #filtration #flow #gravity
Saturday, June 16, 2012
Focus: System Flow Decisions have been made! With flow method and battery selected, we move onto pumps.Entry:
Maneesh and Dylan made a presentation for discrete flow. The system seems to be complicated, as it involves pressure gradients and the use of feedback loops and modifiers to generate pressure equalization. Since simplicity is a top priority, we returned to continuous flow because it would be easier to implement and still fulfill the functional requirements. During further discussion, we did a back-of-the-envelope calculation for a continuous flow rate of water. It came out to be 0.03 milliliters per minute, which meant we needed a very precise, slow-acting pump. For the purpose of conserving energy, Dan found some low power pumps, including a $5 Chinese manufactured pump and a $20 500 GPH (gallons per hour) bilge pump. However, more research is required to find the optimal pump. We also thought about methods for introducing food into the stream. One idea was to use a worm-gear compressor to slowly push through our system. Chie presented candidates for our biosensor battery. We selected a 100Ah deep cycle gel cell battery, after listening to suggestions from several professors. Lydia and others discussed meeting with ECE professors to figure out the logistics of the circuitry component. We have a rough plan for developing the potentiostat, which is vital for measuring changes in potential, or signal produced by the bacteria when they detect toxins in the water. #flow #pump #battery #potentiostat
