1. Final Prototype Presentation Dec 9, 2008

2. Today’s Presentation: Motivation Materials Selection Materials Processing Tube Fabrication T-Joint Fabrication Design Stages/ Final Prototype Cost Analysis Future Work/ Acknowledgment

3. Motivation  Solve the world Problems MIT Engineers Use current understandings of materials structure, properties and processing techniques  Develop a Recyclable, Cost Effective and Easily Processed Drip Irrigation System

4. Materials Selection Criteria: Low Cost of Material Environmentally friendly W idely available in Ethiopia Low Cost of Processing Chemically inert Resistant to fresh water/ salt water Resistant to UV radiation (sun in Ethiopia)

5. Ashby Plot of Recycle vs Polymer Extrusion Energy

6. Materials Selection T joints  HDPE rods Tubes  HDPE form plastic bags

7. Materials Processing Grinding Machine HDPE Plastic Bags   Shredded Plastic bags Use 75% LDPE pellets—25% HDPE shredded bags for tube fabrication

8. Tube Fabrication (Blown Film Processing) Film Blowing MachineTube Fabrication Steps

9. T-joint fabrication T- joints constructed by making holes in HDPE cylinders (simplicity one of the main goals of the design) 

10. Tube/ T-Joints Construction Tubes attached to the joints using a hot melt gun.

11. Design Decision Process Identifying need for cheap and simple Drip Irrigation System (DIS) for Ethiopia Filter & Emitter Design Modification of Design : Exclude filter and emitter for simplicity T joint & Pipe design Modification of Design: Thin tubing for easier processing Modification of Design: Multi- component T joint to prevent leakage Final Product

12. Cost Analysis Total Cost = 2.69 per system Materials Cost – $0.85 for injection molded water tap – $0.80 for 48 feet of tubing (including 5% rejection rate) – $0.70 for joints, elbows Utilities Cost – $0.03 per system based on current costs of electricity Other Costs (Rent, Machinery, Delivery) – Not included – Rent = $14 per system – Sunk $77 per system after 1 years $15 per system after 5 years Problems include high costs of machinery Labor Costs – would have to be $0 to make this reasonable without much funding

13. Looking back at goals after Alpha Prototype Better T and Y joints Better/ more stable attachments of tubes to the joints Tube of uniform diameter Greater number of tubes (a larger drip irrigation system) Fabrication of filter for grey water

14. Our thoughts Like all other engineering designs, there is a lot of room for improvement and adding different functionalities (filter, emitters, valves…) to the Drip Irrigation System. We tried to use our knowledge of materials and make the best use of resources available to develop a functional prototype… But, we would not have been able to go the DISTANCE without endless help and support from the faculty and staff for 3.042 and Engineers at U.S Army Natick Research Center…

16. Any Questions?