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Microbial Detection Arrays

Microbial Detection Arrays. MiDAs. October 23 rd , 2006 Aerospace Senior Projects University of Colorado - Boulder. Team Members . Elizabeth Newton – Project Manager Shayla Stewart – Systems Engineer Steven To – Chief Financial Officer Dave Miller – Fabrication Engineer

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Microbial Detection Arrays

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  1. Microbial Detection Arrays MiDAs October 23rd, 2006 Aerospace Senior Projects University of Colorado - Boulder

  2. Team Members • Elizabeth Newton – Project Manager • Shayla Stewart – Systems Engineer • Steven To – Chief Financial Officer • Dave Miller – Fabrication Engineer • Ted Schumacher – Lead Thermal Engineer • Jeff Childers – Lead Structural Engineer • Charles Vaughan – Lead Electrical Engineer • Sameera Wijesinghe - Webmaster

  3. Briefing Overview Jump to • Overall Objectives • System Design Alternatives • Design-To Specifications • Thermal Design Options • Structural Design Options • Electrical Design Options • Project Feasibility and Risk • Project Plan • Appendices Look for me for further info

  4. Overall Objectives Picture from www.physics.byu.edu

  5. Objectives Overview • Objective: To design and build a field-ready unit capable of providing a testing environment for electrochemical sensors to detect microbial life by soil analysis • Deliverables: • Field-ready unit • Test data verifying requirements • Operational manual for use Electrochemical sensors • Sensors developed by Tufts University and BioServe • Sensors analyze soil for metabolic indicators such as pH and chemical composition and convert them to electronic signals • Assumes that life only needs water and nutrients found in native soil to metabolize

  6. Geological Sample Inoculation Sample Soil Sterilization Power Reagent Water Temperature Control Temperature Control Temperature Control Sensors Test Chamber Control Chamber Mixer Mixer Data Acquisition and Control Functional Diagram • Accept soil • Sterilize soil using an autoclave • Add reagent water • Move soil to reaction chambers • Add non-sterile inoculation sample to test chamber • Mix soil and water while starting temperature control • Testing lasts for two weeks

  7. Functional Requirements • Must be capable of performing in extreme Earth conditions • McMurdo Bay, Antarctica -10°C to 2°C (during summer) • Atacama Valley, Chile -6°C to 38°C • Must provide and function with power comparable to next-generation Mars science rovers (30 Watts) • Must be portable (30 kg) Pictures from Wikipedia.org

  8. Overall Architecture: Environmental Controls Sterilization Chamber Separate Separate Assessment of System Design Alternatives • Quantitative analysis of cost, mass, and volume based on rough estimates • Ultimately, complexity became primary consideration Pro -Reaction chambers at same temperature -No need to heat/cool each chamber individually Con -No way to correct if one chamber is warmer than the other -More volume to heat/cool Pro -No need for extra environmental chamber Con -Each reaction chamber must be heated/insulated Shared Pro -Only one chamber must be fabricated -Only needs one heater Con -Soil must be separated into test/control chambers after sterilization • Shared Environment • Separate Sterilization Chambers Shared Pro -No need for soil separation: reduced complexity Con -Two chambers and two heaters

  9. System Design Alternatives End Result • Separate Autoclaves • Shared Environment

  10. Design-To Specifications • Thermal Subsystem • Mass: 16.3 kg • Volume: 0.096 m3 • Cost: $660 • Structural Subsystem (excluding chassis) • Mass: 11.3 kg • Volume: 0.00293 m3 • Cost: $280 • Electrical Subsystem (excluding power supply) • Mass:0.30 kg • Volume:0.00045 m3 • Cost:$1340 • Overall System • Mass:27.9 kg • Volume:0.09938 m3 • Cost:$2280 • Total Funds: $8000

  11. Overall System Architecture Autoclaves Water Chamber Pump Inoculation Chamber Test Chambers DAQ/Power TEC

  12. Work Breakdown Structure

  13. Thermal Design Options Pictures from melcor.com, minco.com, wikipedia.org, energysolutionscenter.org

  14. Insulation Options • Insulation applications • Autoclave chambers • Environmental chambers • Reagent water chamber • Inoculation sample chamber • Insulation Requirements • Minimize power needed to heat chambers • Protect electrochemical sensors from heaters • Criteria (order of importance) 1. Volume (thermal conductivity, k) 2. Complexity 3. Cost

  15. Insulation Option Pros and Cons Additional Options for Heating and Cooling

  16. Structural Design Options Pictures from trendir.com, polypenco.co.jp, sonozap.com, sciencelab.com, parker.com

  17. Material Options • Material applications • Autoclave chambers • Must be able to withstand high temperatures and pressures • Must be corrosion-resistant • Environmental, inoculation, and reagent water chambers • Need to be lightweight • Reaction chamber • Must be able to be sterilized • Must be inert • Criteria (order of importance) 1. Mass 2. Complexity (machineability) 3. Cost

  18. Material Pros and Cons Additional Options forSoil/Water Transportationand Mixing

  19. Electrical Design Options Pictures from spectrolab.com, fuelcellstore.com, dpie.com, weedinstrument.com

  20. Power Supply Options • Power supply requirements • Power supply must provide 30 W of power • Must power the MiDAs instrument for duration of experiment (17 days) • Criteria (order of importance) • Cost • Mass • Volume

  21. Power Supply Pros and Cons Additional Options forData Acquisitionand Pressure/Temperature Sensors

  22. Feasibility and Risk Picture from http://www4.macnn.com/games/gamecenter/risk2/s_01_lrg.jpg

  23. Project Risk Assessment Green Subsystems= Low RiskYellow Subsystems = Medium RiskRed Subsystems= High Risk

  24. Autoclave Feasibility Assumptions • Fluid inside is only water (high specific heat of water will give maximum boundary) • Insulation radius = 10 cm of material (thermal conductance of k = 0.012 W/m °C) • Internal and external losses and safety margin = 2.4W (20% of heating/cooling capacity) • Specific heat (Cp) for 316 steel = 452 J/kg K • Specific heat (Cp) for water = 4230 J/kg K • Heater uses 12 W per chamber • Standard autoclave techniques implies • 121°C, hold for 15 min • Cool to 20°C, hold for 24 hours • Repeat 3 times

  25. Autoclave Feasibility Analysis • Time to heat from -10°C to 121°C = 3.9 hours • Time to cool to 20°C = 117 min with active cooling • Power: • 3.9 amp hours to heat • 0.04 amp hours to hold for 15 minutes • 1.95 amp hours to cool • 3.36 amp hours to hold for 24 hours = 79.8 C/W Rconduction =

  26. Autoclave Solution and Verification • Solution: • Sterilization chamber mock-ups will be made and tested with various heaters and insulation to verify that it is possible to achieve 121°C • Verification: • Temperature and pressure sensors will be used to verify that a sand/water solution can reach 121°C on 30 W of power

  27. Autoclave Power Summary

  28. Mixing Feasibility Analysis • Requirement: • Soil and water must be mixed within the reaction chambers • Reduces boundary layer so electrochemical sensors can read correctly • Prevents soil sedimentation • Problem: • Difficult to find mixers small enough to fit in reaction chambers • Flow pattern difficult to analyze without testing • Unknown if ultrasonic mixers can be used at appropriate frequency • Magnetic stirrers may affect electrochemical sensors

  29. Mixing Solution and Verification • Solution: • Mock-ups of reaction chambers will be prototyped and tested with various mixers • Different soil granularities will be tested • Various mixing regimes will be tested • Continuous mixing • Pulsed mixing • Verification: • Flow patterns and soil sedimentation will be visually analyzed to show that various types of mixing regimes and mixers provide adequate stirring

  30. Project Plan Picture from http://www.connectedconcepts.net/clip%20art/Project%20Plan.gif

  31. Organizational Chart

  32. Schedule Through CDR

  33. Schedule Through CDR

  34. Schedule Past CDR • Machining: • Assume one chamber machined per week • Last Machining Day – March 16, 2007 • Testing: • Subsystem testing can begin as soon as each chamber is constructed • Overall testing: March 16, 2007 – April 17, 2007 • Final Review – April 17, 2007 • ITLL Expo – April 28, 2007 • Final Report – May 3, 2007

  35. Conclusions • Project is feasible • Budget is one-quarter of funds • Mass is 34 kg, which is portable • Initial calculations and research indicate that high risk subsystems (mixing and autoclaving) are challenging but possible • Further analysis through prototyping will be performed before CDR • System is capable of performing in specified environments • System is capable of performing with 30 W of power • Many options are available to meet each requirement • This allows off-ramps in case some options are dismissed during design

  36. Questions/Comments? Picture from http://content.answers.com/main/content/wp/en/thumb/5/5b/250px-Nasa_mer_marvin.jpg

  37. References • Cengel, Yunus. Introduction to Thermodynamics and Heat Transfer. • McGraw-Hill.University of Nevada, Reno. 1997 • Gilmore, David. Spacecraft Thermal Control Handbook. Aerospace press. El Segundo, California. 2002 • www.aerogel.com • www.dimondsystems.com • www.matweb.com • www.mcmaster.com • www.melcor.com • www.minco.com • www.omega.com

  38. Appendix Table of Contents • System Architecture Options • Chamber Geometries • Verification Methods • Power Model and Budgets • Operational Environment • Subsystem Options, Trade Studies, and Pros and Cons

  39. Appendix A: System Parameter Estimates

  40. Assessment of System Design Alternatives Quantitative Analysis of Options Mass, volume, and cost figures do not include components that all options need the same number of, such as a reagent water tank and mixers.

  41. Option A • Sterilization and testing occur in same chamber • Requires: • 1 large autoclave • 2 moving sensor packages • 2 motors • 2 environmental sensors • High complexity from moving sensor packages Mass: 1000 g Volume: 4842 mL Cost: $600

  42. Option B • Shared sterilization, separate environment • Requires: • 1 large autoclave • 2 reaction chambers • 2 soil transport tubes Mass: 900 g Volume: 4444 mL Cost: $150

  43. Option C • Shared sterilization, separate environment • Requires: • 1 large autoclave • 2 reaction chambers • 2 soil transport tubes • 6 environmental sensors Mass: 1200 g Volume: 4504 mL Cost: $1350

  44. Option D • Separate sterilization, separate environment • Requires: • 2 small autoclaves • 2 reaction chambers • 3 soil transport tubes • 8 environmental sensors Mass: 1400 g Volume: 4612 mL Cost: $1750

  45. Option E • Separate sterilization, shared environment • Requires: • 2 small autoclaves • 2 reaction chambers • 3 soil transport tubes • 6 environmental sensors Mass: 1300 g Volume: 4592 mL Cost: $1350

  46. Autoclave Chamber Geometry • Assumptions of a possible design: • Chamber is made of 316 stainless steel • 5 mL water added to chamber for use in autoclaving • 15 mL space provided so sample is not tightly packed • Chamber is a cylinder • Dimensions: • Total internal volume of chamber = 45 mL • Internal diameter = 2.54 cm • External diameter = 3.04 cm • Wall thickness = 0.25 cm • Length = 9.38 cm • Mass = 0.19 km

  47. Reaction Chamber Geometry • Assume: • Chamber is made of Ultem 1000 • Chamber wall thickness of 0.5 cm • Inside chamber geometry is a cylinder • 20 mL additional space for mixing (70 mL total volume) • Dimensions: • Walls: 0.5 cm thick • Outside diameter = 3.95 cm • Height = 11.28 cm • Mass = 0.0866 kg Drawings by Jake Freeman

  48. Top View Side View Environmental Chamber Geometry • Assume: • Chamber is a cube containing both reaction chambers • Buffer around chambers is 3 cm with 2 cm between them • Dimensions: • Height: 17.28 cm • Depth: 9.95 cm • Width: 11.95 cm • Volume: 2054.635 cm3

  49. Reagent Water Chamber Geometry • Assume: • Chamber is a cylinder • Water expands upon freezing • Dimensions: • Height: 2.1 cm • Radius: 3.0 cm • Volume: 60 cm3 Side view

  50. Verification Methods

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