Department of Horticulture and Landscape Architecture

SEMINAR

Dr. S. Edward Law University of Georgia Electric Force-Field Control of Agricultural & Biological Particulates: Review of Underlying Principles, Engineering Development & Implementation Biological scientists routinely rely upon interactive electric and magnetic forces, as based upon the Lorentz equation, to control the motion of electrons and ions within scanning and transmission electron microscopes and mass spectrometers. For larger micron-size charged particulates at atmospheric pressure, the incorporation of the Lorentz electric-force component likewise provides effective “electrostatic” control of the motion, attraction and/or deposition of solid and liquid agents in numerous real-world commercial and industrial processes including, for example: xerography, ink-jet printing, cell sorting, abrasive-paper manufacturing, textile flocking, materials separation/sorting, electrostatic-precipitation of combustion air pollutants, and the electrostatic coating/spraying of automotive finishes, surface disinfectants, body-tanning solutions, pollen suspensions, agricultural pesticides, etc. These diverse electrostatics processes share a common foundation in charged-particulate physics; as way of review this seminar will thus focus upon the underlying physics, engineering development, and implementation of air-assisted, electrostatic-induction, crop-spraying technology as currently patent-licensed by the University of Georgia Research Foundation. Sustainable and effective crop production would benefit by implementation of improved spray-application technology which, as compared to conventional hydraulic-pressure-nozzle spraying, dispensed significantly less (e.g., 1/4-1/2) pesticide active ingredient into the ecosystem while achieving the required deposition on-target for economic/efficacious pest control. To accomplish this goal, the hybrid air-assisted electrostatic crop-spraying process as proven at the University of Georgia: a) purposefully atomizes reduced volumes (e.g., 10-60 L/ha) of conductive (e.g., 10-4-101 S/m) water-based spray liquids into small droplets (e.g., 30-40 µm VMD); b) imparts to them high droplet charge-to-mass (e.g., 10 mC/kg) via an electrostatic-induction electrode embedded within the nozzle safely using low-voltage/low-power (e.g., 1 kV/1 watt) electronics; c) aerodynamically propels (~3-6 m/s) the charged spray cloud to the target plant canopy and turbulently mixes it therein via an air-carrier stream (~300 watts) inherent within the pneumatic nozzle; and d) incorporates primarily space-charge electric force fields (~1-3 kV/cm) emanating from the charged cloud itself for depositing the charged spray onto the frontsides/backsides of interior-canopy surfaces under droplet forces typically 10-50 fold greater than gravitational… thus precluding the non-penetrating “fringing” of deposition onto exterior surfaces of “Faraday-shielded” plants characteristic of purely electrostatic crop sprayers relying upon high-voltage (e.g., 40-90 kV) electrodes external to the nozzle. Also reviewed will be electrical interactions occurring between target plants and incoming charged-spray clouds which verify target-grounding adequacy, results showing on-target mass-transfer and pest-control efficacy to be typically 2-5 times greater for electrostatic deposition vs. conventional, as well as backside deposition enhancements. November 19, 2015 3:30 pm HORT 117 Reception at 3:10 pm HORT 117 *Seminar will be recorded If you are interested in meeting with the speaker, please contact Jennifer Deiser at 41301 or jdeiser@purdue.edu