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CIQ Workshop

CIQ Workshop. November 30 th – December 1 st 2010. Understanding the Nature of HVI Data. Cotton is a biological fiber with natural variability in its properties HVI data has natural variability due to cotton variability plus testing variability or error (normal & abnormal)

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CIQ Workshop

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  1. CIQ Workshop November 30th – December 1st 2010

  2. Understanding the Nature of HVI Data • Cotton is a biological fiber with natural variability in its properties • HVI data has natural variability due to cotton variability plus testing variability or error (normal & abnormal) • Strive to control and minimize abnormal testing variability • Accept and manage the normal variability

  3. Cotton Plant • Matures from bottom to top • Cotton at bottom develops first and cotton at top develops last • Cotton at top and further from the trunk exhibits lower properties for micronaire, length, uniformity index and strength due to less time for growing and cell development.

  4. Fiber Distribution of any Property Mean (average) range

  5. Individual Comb Data

  6. Individual Comb Data

  7. Understanding the Nature of HVI Data Example: 1 Bale of Cotton tested: 100 times x 1 HVI x 1 day 100 times x 1 HVI x 2 days 100 times x 2 HVI x 2 days 100 times x 9 HVI x 2 days

  8. Understanding the Nature of HVI Data Example: 1 Bale of Cotton tested: CV (Coefficient of Variation) Mic Length SFI 100 x 1 HVI x 1 day 1.75 1.04 5.11 100 x 1 HVI x 2 days 1.80 1.10 5.14 100 x 2 HVI x 2 days 1.87 1.17 9.16 100 x 9 HVI x 2 days 1.99 1.38 16.49

  9. Understanding the Nature of HVI Data Fiber Distribution Important Points: - HVI data is statistical in nature - Even the best HVI data has an accepted level of variability (error)

  10. Precision and Bias Not precise, no bias

  11. Precision and Bias Precise, with a bias

  12. Precision and Bias Precise with no bias

  13. FIBER PROPERTIES 101.2

  14. Fiber Properties Measured • Micronaire • UHM Length • Uniformity Index • Strength • Color Rd • Color +b • Trash Percent Area • Trash Count

  15. FIBER PROPERTIES Micronaire– air flow system, consisting of a balance & a balanced bridge with a chamber which measures the fineness and maturity of the cotton fibers. • A sample of known mass is compressed into a fixed volume and subjected to a standard air pressure.

  16. FIBER PROPERTIES • Length – is the average length of the longer one-half of the fibers (upper half mean length) • Reported in mm’s, 100ths & 32nds of an inch • Measured by passing a “beard” of fibers through a sensing point. This beard is formed when a comb grasps fibers from a cotton sample, which then are combed and brushed to straighten & parallel them.

  17. Fibrogram Amount (Light Attenuation) Length (Steps) 101.2

  18. FIBER PROPERTIES • Length Uniformity Index– is the ratio between the mean length and the upper half mean length of the fibers and is expressed as a percentage. • If all the fibers in the sample were the same length, then the uniformity index would be 100 • Because of this, the index will always be less than 100.

  19. UHM & UI from the Fibrogram 100% SL Amount 50% SL UI = (ML / UHML) x 100 ML UHML Length 101.2

  20. FIBER PROPERTIES • Strength – reported in grams per tex. • A tex unit is equal to the weight in grams of 1000 meters of fiber. Therefore, the strength reported is the force required to break a bundle of fibers one tex unit in size.

  21. Stress / Strain Curve Force Distance 101.2

  22. FIBER PROPERTIES • Color – determined by the degree of reflectance (Rd) & yellowness (+b) as established by the official standards and measured by the HVI • Reflectance – how dull or bright (degree of grayness) the sample is • Yellowness - indicates the degree of yellow color pigmentation

  23. USDA Color Grade Diagrams

  24. FIBER PROPERTIES • The Rd on a scale of 0 to 90, and the +b on a scale from 0 to 20 are converted to a three digit color code determined by plotting the intersecting points on the USDA color diagram.

  25. FIBER PROPERTIES • Trash – A surface measure of the amount of non-lint material in a cotton sample measured in terms of the percent area of trash and particle count. • Determined by scanning a compressed cotton sample through a CCD video camera whose image is converted to a digital picture. The picture elements (pixels) that are below a preset level will be black, and those pixels are counted as trash. • Percent area of trash is calculated along with a trash particle count.

  26. Cotton Division Locations • Washington Headquarters • Memphis Field Headquarters / Classing Office • Classing Facilities

  27. Facilities & Equipment • Classing Office Locations (10) • Florence, South Carolina • Macon, Georgia • Rayville, Louisiana • Memphis, Tennessee • Dumas, Arkansas • Corpus Christi, Texas • Abilene, Texas • Lamesa, Texas • Lubbock, Texas • Visalia, California • HVI numbers per location (245) 22 34 17 44 17 16 14 12 43 26

  28. Cotton Division Locations 2040 sq meters 2500 sq meters 7800 sq meters 1200 sq meters

  29. HVI 1000’s by Year Model in USDA Classification Service Year # 40 50 48 40 30 20 10 Total: 238

  30. INSTRUMENT CALIBRATION • Two Points Micronaire value Low to high Low to high Instrument analog measurement value (voltage)

  31. INSTRUMENT CALIBRATION • Five Points Low to high Color Rd value (reflectance) Low to high Instrument analog measurement value (voltage)

  32. INSTRUMENT CALIBRATION • Five Points Low to high Color +b value (yellowness) Low to high Instrument analog measurement value (voltage)

  33. Proper Calibration • Use of correct materials • Clean materials (No contamination) • Current materials • Follow proper procedures • Placement of materials into instrument • Handling of materials Conditioning of Materials for Moisture sensitive measurements • Stored in testing environment • Moisture equilibrium • Consistent environment • CALIBRATION

  34. Overview • Conditioning • Compressed Air • Conveyance • Removal • HVAC

  35. How Facilities Systems Support the Grading Process • HVAC System • Ensures proper testing conditions for lab and receiving areas, and provides conditioned air for Rapid Conditioning Units (RCUs). • Conditioning System • Brings cotton to proper testing levels. • Compressed Air System • Supplies air for High Volume Instruments (HVIs) and Conveyance Systems • Conveyance System • Brings samples into the grading process. • Loose Removal System • Removes completed samples from the grading process.

  36. Monitoring Conditions • Sensors in ceiling-mounted boxes monitor temperature and humidity levels. • Wall displays show temperature and humidity levels. • Sling or electronic psychrometers provide a manual check of conditions.

  37. Sample Moisture • Moisture content monitored with moisture measurement probe such as following: • StrandburgMoisture Meter 101.6

  38. Conditioning Systems

  39. Testing Conditions • To ensure proper testing level, all cotton samples must have a moisture content of between 6.75 and 8.25 percent (dry weight basis). • To achieve this moisture content, classing and receiving areas are kept at specified temperature and relative humidity levels: • Temperature: 21 C, +/-1 • Relative Humidity: 65% RH, +/-2

  40. Passive Conditioning (Rack) • Background • Only method of conditioning prior to RCU • Large conditioning space required • Providing such space is costly • Samples are placed in single layers • Samples must be exposed to conditioned space until the specified moisture level is reached (minimum of 48-hours )

  41. Active Conditioning (RCU) • Background • RCU developed in 1993 • Conditioned air is drawn through the samples • Air is discharged back into return to be reconditioned • Conditioning time is approximately 10 minutes • Smaller conditioning space is needed

  42. Moisture Affect on Measurements 28 27 Fiber Strength (g / tex) 26 25 24 55 60 65 70 75 80 Relative Humidity (% RH) 101.5

  43. Effect of Moisture on Fiber Properties • 1% Moisture Content ~ 10% unit change in Relative Humidity(RH) • Strength – 1% MC change ~ 5% change • Length - 1% MC change ~ 2% change • Micronaire-1% MC change ~ 2% change 101.6

  44. Effect of Moisture on Fiber Properties • Example RH MC MicStr Len 60% 6.5% 4.00 30.0 1.00 70% 7.5% 4.08 31.5 1.02 101.6

  45. American Society for Testing and Materials InternationalASTM-I • Designation: D 7410 – 07 Standard Practice for Qualification of Cotton Classification Instruments for Cotton Marketing Scope 1.1 This practice provides two options for the qualification of cotton classification instruments: option 1, newly installed cotton classification instrumentation, or option 2, annual verification of cotton classification instrumentation using evaluation cottons, trash evaluation images, and color evaluation fiber samples for the fiber measurements of micronaire reading, upper half mean length, uniformity index, breaking tenacity (strength), Rd (color reflectance), +b (color yellowness), percent area (trash), and particle count (trash).

  46. Qualification Materials and Procedures Conditioning Condition the cotton samples a minimum of 48 hours according to the temperature and relative humidity levels as specified in Practice D 1776 (21°C plus or minus 1°C) and (65 +/- 2 %). Calibration The cotton classification instrument shall be calibrated using USDA calibration materials as specified according to the instrument manufacturer instructions.

  47. Qualification Materials and Procedures • Evaluation Cottons • Color Evaluation Fiber Samples • Trash Evaluation Images

  48. Qualification Materials and Procedures Procedures Materials to test Number of test repetitions Data captured and required precision Data analysis Mean (Average) Standard deviation Criteria required for Pass / Fail

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