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CUTTING EDGE TECHNIQUES TO MEASURE DROPLET SPECTRUM AND CHEMICAL DEPOSITION OF PESTICIDE SPRAY

CUTTING EDGE TECHNIQUES TO MEASURE DROPLET SPECTRUM AND CHEMICAL DEPOSITION OF PESTICIDE SPRAY. Muhammad Farooq US Navy Entomology Center of Excellence, Jacksonville, FL.

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CUTTING EDGE TECHNIQUES TO MEASURE DROPLET SPECTRUM AND CHEMICAL DEPOSITION OF PESTICIDE SPRAY

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  1. CUTTING EDGE TECHNIQUES TO MEASURE DROPLET SPECTRUM AND CHEMICAL DEPOSITION OF PESTICIDE SPRAY Muhammad Farooq US Navy Entomology Center of Excellence, Jacksonville, FL

  2. The views expressed in this presentation are those of the author and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, or the U. S. Government. Disclaimer

  3. Spray Application

  4. Coated Slides Coated with MgO, teflon, gelatin, petroleum, resins Impressions or stains are measured Droplet size determined indirectly Mainly suitable for laboratory measurements due to handling issues Intrusive Methods

  5. Water Sensitive paper Oil Sensitive paper Coated Films Glossy Paper Leaf Surfaces Liquid Media Intrusive Methods

  6. Cascade Impactors Air sampled Droplets segregated by inertial separation Amount on each stage related to droplet size Intrusive Methods Air speed increases and droplet size decreases Source:www.envcoglobal.com

  7. Fibrous Media Droplets captured on fibers Droplet size measured directly Research on ways to measure droplets on fibers lead to development of Army Insecticide Measurement System then DCIII Intrusive Methods Source: CAB International, 1993

  8. DCIII Portable Droplet Counter

  9. Reading slides Manually using microscope Enhancement of Analysis Techniques for Intrusive Methods Drop Vision System that scans slide in to computer that measures the droplet sizes

  10. Microscope with digital image processor Slide Droplet Image Analysis software Graphing & Reporting software Drop Vision

  11. Sensitive Paper Reading System Scanned as Bitmap Cards Image analyzed with Stainalysis or with WRK Image Analyzer Droplet size Droplet density Percent coverage of card surface

  12. Reading of Collected Droplets by Photography Source: Aalborg University, Denmark, Website

  13. Photographic Measurements Holographic Optical Array Spectrometer Light Scattering Laser Doppler droplet sizing Non-Intrusive Methods

  14. Frozen image by Short duration high intensity light Mercury vapor lamp, electric spark and flash => 1 ms duration Laser pulses => order of ns High speed camera Images read by image analysis programs Two pulses => Droplet size and velocity Photographic Measurements

  15. Frozen Image

  16. Photomicrography Rathburn & Miserocchi, JEE, Feb. 1967

  17. Laser Imaging Source: www.oxfordlasers.com

  18. Image Analysis for Size and Velocity Source: www.oxfordlasers.com

  19. Frozen Image of fast moving object Source: www.oxfordlasers.com

  20. Fringe pattern produced by out of focus imaging Number of fringes related to droplet size Droplet size and 3-D Velocity Number density Mass Flux Size-Velocity correlation Interferometric Mie Imaging Source: www.LaVision.de

  21. Shadography High Magnification Image for visualization Sizing by image analysis Droplet size, shape and 2-D Velocity Number density, Mass Flux Size-Velocity correlation Source: www.LaVision.de

  22. Particle Image Velocity 6-10 ns image 100 ns time between images Source: www.LaVision.de

  23. Digital Image Correlation Source: www.LaVision.de

  24. Particle Master Size and Velocity of droplets Spray Master Visualization of spray Flow Master Study of flows Strain master Deformation of flows or materials under stress Systems Developed

  25. Holography The image can be reproduced with laser to measure droplets

  26. Optical Array SpectrometersPrinciple Number of obscured diodes related to droplet size Source: CAB International, 1993

  27. Light Scattering Methods Light Intensity Technique Forward scattering spectrometer probe (FSSP) Laser Diffraction Technique Malvern droplet sizing system Sympatec droplet sizing system

  28. Light Intensity Technique Source: CAB International, 1993

  29. Laser Diffraction TechniquePrinciple Source: CAB International, 1993

  30. Laser Diffraction Technique Location of droplet in the beam does not effect the size determination Source: www.sympatec.com

  31. Use He-Ne class 3, 632.8 nm laser Spatial measurement systems Easy to set-up and align Provide volume distribution of droplet size Data Rate up to 10 kHz Size range Malvern: 0.1 to 2000 mm with two lenses Sympatec: 0.1 to 3500 mm with 8 lenses Laser Diffraction Technique

  32. Measurement /probe volume Laser Beam splitter Detector 1 Detector 3 Detector 2 Laser Doppler Droplet SizingPrinciple Measurement volume

  33.   Filtered signal Frequency of the signal related to droplet velocity Phase shift related to droplet size Doppler Signal Laser Doppler Droplet SizingPrinciple

  34. General Features of PDPA • The PDPA is a flux sampling instrument(single particle counter) • Provides simultaneous measurement of velocity and size of spherical particles • Particle size between ca. 0.5 µm and several millimetres • Can analyze many spray characteristics. The most important are: • Droplet number distribution • Droplet volume distribution • Droplet velocity distribution • Droplet concentration and Liquid Water Content • Turbulence intensity • Droplet size velocity correlation

  35. Droplet Size-Velocity Correlation

  36. Data Extraction

  37. Summary Data

  38. Portable Particle Counters Air contamination studies Air suction system Laser-based or centrifugal impaction Droplet size range: 0.3 – 20.0 µm Flow rate: Up to 100 L/min Solid particles in gases or liquids Looking for one to measure liquid droplets in air

  39. PDI Flight probe Funded by US Navy for cloud and plane icing studies Based on Laser Doppler sizing principle Design being optimized Source: Artium Technologies Inc.

  40. Spray Application

  41. Fundamental part of sprayer evaluations in agriculture Practices in public health Bio-assays Droplet size characteristics These techniques do not: Approve or disapprove the delivery system Elucidate the shortcomings of the equipment being tested Lead to improvements for meeting the objective Why Deposition?

  42. Deposition Measurement Sampling Quantification may include extraction

  43. Indicating Samplers Plant species for herbicides Sensitive Paper Water sensitive Oil sensitive Samplers

  44. Passive Samplers Cylindrical collectors Paper Mylar Sheet Plant Leaves Cotton squares Filter papers Plastic tapes Cotton ribbons Samplers Useful for coursehigh volume agricultural sprays

  45. Active samplers Air Samplers Rotating samplers Samplers Useful for sub-micron particles and ULV space sprays

  46. Air Samplers Air drawn over a filter medium Flow rate known Sampling time recorded Quantity of spray determined analytically. Result: Concentration of spray in air Concentration is a measure of flux

  47. Air Sampler Settings Source: CAB International, 1993

  48. Rotary Samplers Rotorod Sampler

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