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Quality Control for PH of Tea

Quality Control for PH of Tea. Final Presentation. YU Jiayi , CUI Liwen , CHEN Rui , GUO Dingcheng , CAO Qing. Project Overview. Suggestions. PH value. DOE. Gage R&R. Off-line Experiments. Project Overview. Define (1/3). Study Problem

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Quality Control for PH of Tea

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  1. Quality Control for PH of Tea Final Presentation YU Jiayi, CUI Liwen, CHEN Rui, GUO Dingcheng, CAO Qing

  2. Project Overview Suggestions PHvalue DOE Gage R&R Off-line Experiments

  3. Project Overview

  4. Define (1/3) • StudyProblem • Asthe PH value of tea beverage is an important quality index, wewouldliketostudythefactorsthatwouldaffectthePHvaluethroughoff-line experiments. • WeexpecttoobtaintherecommendedvaluesoftherelatedinfluencefactorstoobtaintherecommendedPHvalue,thusguidingtherealproductionoftea beverage.

  5. Define (2/3) • Response (y) • PH value of tea beverage • Green Tea: PH value of 6.2 recommended • Factors (x) • Temperature • Time • Percentage of Tea • Container (stainless steel, glass, ceramic, etc.)

  6. Define(3/3) • Methodology: Design of Experiment • Off-line experiments • Gage R&R study • GLM • Identify significant factors • Specify relationships between x and y

  7. Project Overview

  8. Measurement Instruments Temperature-control Pot Measuring Cup Electronic PH-meter Electronic Scale

  9. Gage R&R (1/6) • Experiment setting • pH meter • 3 operators • 3 cups of tea • 3 replicates • Parameters • 3g tea • 200 mL water • 8 min

  10. Gage R&R (2/6) • Experiment without SOP • Effect of operatoris significant • Contributions of total Gage R&R: nearly 100% • Repeatability: 62.57% • Reproducibility: 37.43%

  11. Gage R&R (3/6) • Experiment without SOP

  12. Gage R&R (4/6) • Experiment with SOP • Effect of partand interactionare significant • Contributions of total Gage R&R: 35.21% • Repeatability: 14.72% • Reproducibility: 20.49%

  13. Gage R&R (5/6) • Experiment with SOP

  14. Gage R&R (6/6) • The gage has acceptable repeatability and reproducibility • Different operations of operators have large influence in R&R • A proper SOP is required to improve the performance of operators

  15. Project Overview

  16. Design of Experiment (1/2) • fractional factorial design • Response variable: pH value (using pH meter) • Tea: 憩园甘露 • Initial model:

  17. Design of Experiment (2/2) • Sequence of experiment • Three cups of tea are tested in the same period. • The cups are made of different materials. • The total time of each cup is different. • Measure their PH at their own time point. • Control of factors • Temperature: air-conditioner, thermos • Volume of water: measuring glass • Weight of tea: electronic balance

  18. Design of Experiment 0 min 2 min 4 min 不锈钢 陶瓷 玻璃 8 min 7 min 6 min 8-0=8 min 7-2=5 min 6-4=2 min

  19. Experiment process (1/4) • Experiment notes • Cleaning acidometer & container everytime after reading PH value to get accurate data • Put acidometer into tea at least 1 min before reading to get stable PH value • To save time, we compress 3 experiments into one 8 min cycle, with same water temperature

  20. Experiment process (2/4) • Preparation • Make sure the 3 experiments’ parameter combination (3g tea-leaf, same temperature) • 2min, A mL water, B1 container • 5min, A mL water, B2 container • 8min, A mL water, B3 container • Measuring required water & three 3g tea-leaf • Put tea-leaf into 3 container

  21. Experiment process (3/4) • Experiment cycle Pour A mL water into B3 container Pour A mL water into B2 container • Read PH value • Wash acidometer • Put acidometer • into B2 container • Wash B3 container • Pour A mL • water into B1 • container • Wash acidometer • Read PH value • Wash acidometer • Wash B1 container 0 min 1 min 2 min 3 min 4 min 5 min 6 min 7 min 8 min • Read PH value • Wash acidometer • Put acidometer into B1 container • Wash B2 container Measuring A mL water Measuring A mL water Put acidometer into B1 container 8 min 5 min 2 min

  22. Experiment process (4/4) Measure 3gtea Experiment Snapshots All experiment instruments Read PH value 3 cups per cycle

  23. Design of Experiment (1/9) • Resultof the initial model • All main effects are significant • Three interactions are not significant

  24. Design of Experiment (2/9) • Residual plot

  25. Design of Experiment (3/9) • Mean of main effect

  26. Design of Experiment (4/9) • Interaction

  27. Design of Experiment (5/9) • Result of model without interaction

  28. Design of Experiment (6/9) • Residual plot

  29. Design of Experiment (7/9) • Mean of main effect

  30. Design of Experiment (8/9) • Residual vs. sequence

  31. Design of Experiment (9/9) • Recommended parameter • Time: 2min • Volume of water: 200ml • Material of cup: Ceramic • Temperature: 98C • Estimated pH: 6.231 • Limitation: no consideration on the effect of • Reusing tea • Type of tea

  32. Project Overview

  33. Improve & Control • ImprovementscanbemadetotheproductionlinetoobtainarecommendedPHvalue • Temperature: 98 ℃recommended • Time:2minutes • Tea/waterratio:3gtea/200mlwaterrecommended • Container:changetheoriginalstainlesssteelcontainertotheporcelaincontainer

  34. Thanks 2014/06/13

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