Initial Studies on the Effects of Droplet Size and Electrostatics on Spray Deposition Efficiencies

2008 ◽  
pp. 61-61-6
Author(s):  
FR Hall ◽  
DL Reichard
Keyword(s):  
Droplet Size ◽  
Spray Deposition

Fading Activities of Herbicidal Droplets Amended with Emulsifiable Spray Adjuvants on Cucurbitaceous Leaves

2018 ◽  
Vol 61 (6) ◽  
pp. 1881-1888
Author(s):  
Jeng-Liang Lin ◽  
Heping Zhu
Keyword(s):  
Weed Control ◽  
Droplet Size ◽  
Spray Deposition ◽  
Herbicide Application ◽  
Spray Droplet ◽  
Coverage Area ◽  
Maximum Coverage ◽  
Fading Time ◽  
Selection Of ◽  
Spray Adjuvants

Abstract. Understanding reactions of surfactant-amended droplets on difficult-to-wet weed surfaces could help develop application strategies to increase herbicide efficacy. Behaviors of herbicidal droplets containing different emulsifiable anti-evaporation spray adjuvants were investigated by characterizing 250 and 450 µm herbicidal droplet dispersion and fading time on cucurbitaceous leaves placed inside a 20°C chamber at 30% and 60% relative humidity (RH). Droplet maximum coverage area increased with droplet size but not with RH, while droplet fading time increased with both droplet size and RH. Despite 450 µm droplets having greater maximum coverage area than 250 µm droplets, the larger droplets had higher fading rates and lower ratios of maximum coverage area to droplet volume. Droplet maximum coverage area and fading time on leaves were affected by adding spray adjuvants to the herbicide-only solution. The Uptake surfactant was more effective than the other two surfactants (AntiEvap+BS1000 and Enhance) in increasing droplet maximum coverage area and fading time. Compared to the herbicide-only solution, addition of Uptake surfactant to the herbicide solution could increase maximum coverage area by 68% and 52% for 250 and 450 µm droplets, respectively, but addition of AntiEvap+BS1000 or Enhance surfactants did not show significant increase. Similarly, addition of Uptake surfactant to the herbicide-only solution increased droplet fading times by 11.1% and 13.2% at 30% and 60% RH, respectively, for 250 µm droplets and by 34.7% and 2.8% at 30% and 60% RH, respectively, for 450 µm droplets. In contrast, addition of AntiEvap+BS1000 surfactant reduced fading time, and addition of Enhance surfactant did not significantly affect fading time. Therefore, appropriate selection of spray adjuvants for herbicide applications could significantly influence droplet deposit behaviors on cucurbitaceous leaves, leading to improved effectiveness of weed control. Keywords: Herbicide application, Spray deposition, Spray droplet, Surfactant, Weed control.

Spray Tip Configurations with Pulse-Width Modulation for Glufosinate-Ammonium Deposits in Palmer Amaranth (Amaranthus palmeri)

2017 ◽  
Vol 60 (4) ◽  
pp. 1123-1136 ◽  
Author(s):  
Alvin Ray Womac ◽  
Galina Melnichenko ◽  
Larry Steckel ◽  
Garrett Montgomery ◽  
Julie Reeves ◽  
...  
Keyword(s):  
Droplet Size ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Spray Deposition ◽  
Test Methods ◽  
Palmer Amaranth ◽  
Published Data ◽  
Current Experiment ◽  
Glufosinate Ammonium ◽  
Extended Range

Abstract. A commercial sprayer operated at a field speed of 24 km h-1 simultaneously applied glufosinate-ammonium through seven spray tip treatments spaced along a 30.5 m boom for measured foliar deposits of herbicide in 35 cm tall Palmer amaranth weeds and spray deposits on foliar-mounted water-sensitive paper (WSP). The experiment followed one that found increased herbicide deposits for dual tips with an adjacent, fore-aft mount, downward-pointed pre-orifice tip (Extremely Coarse) operated with blended pulse-width modulation (bPWM) and a pre-orifice tip (Fine) operated constant (non-bPWM) under moderate ambient wind velocities from 3.1 to 4.1 m s-1. Additional dual-tip treatments were added to the dual-tip configuration for the current experiment to expand droplet Coarseness and to add dual tips operated constant to isolate bPWM effects. Tested treatments in common with the previous experiment included the original dual-tip bPWM and non-bPWM combination, Y-adapter fore-aft-mounted pre-orifice tips with diverging spray patterns both operated bPWM, and an air-induction extended-range tip operated constant. Palmer amaranth weeds, total spray volume rate of 93.5 L ha-1, sprayer speed of 24 km h-1, and test methods were similar between studies, except for negligible wind in the current experiment. Conditions were clear and sunny during spraying without indicators of a stable atmosphere. Overall mean glufosinate-ammonium deposits recovered from leaves were greatest for dual-tips operated constant at reduced droplet size (Very Coarse and Fine) due to reduced required tip size operated without bPWM, and for increased droplet size for Y-adapter-mounted pre-orifice tips (Extremely Coarse and Coarse) operated with bPWM, resulting in overall mean glufosinate-ammonium leaf deposits of 15.9 and 15.0 µg a.i. cm-2, respectively. The combination of dual tips at reduced droplet size or the Y-adapter fore-aft spray pattern divergence of bPWM tips coupled with high sprayer speed enhanced droplet interception by Palmer amaranth plants under negligible wind conditions, since the collected deposits, even without summed integration over foliage height, significantly exceeded the applied rate of 8.2 µg a.i. cm-2. An air-induction extended-range tip non-bPWM (Very Coarse) provided the next highest mean in overall glufosinate-ammonium deposit. One increased-droplet size dual-tip, pre-orifice tip bPWM and non-bPWM (Ultra Coarse and Coarse) resulted in a mean deposit that was not significantly different from the air-induction extended-range tip operated non-bPWM. Other dual-tip combinations with bPWM and non-bPWM, including the original dual-tip configuration in the previous study, resulted in significantly reduced mean herbicide deposits. Considering all tested tips, advantages of bPWM depended on spray tip droplet size classifications and Y-mounted fore-aft divergence of spray patterns. Overall mean WSP spot deposits were greatest for reduced droplet size (Very Coarse and Fine) dual pre-orifice tips operated non-bPWM, corresponding with the highest numerical overall mean of glufosinate-ammonium deposit. This correspondence of highest spot deposits and highest mean glufosinate-ammonium deposit also occurred in the previous study. Increased Palmer amaranth control correlated with increased glufosinate-ammonium deposit and decreased volume median diameter (Dv0.5) determined with WSP electronic scans, with the air-induction extended-range tip operated constant and the Y-adapter pre-orifice tip operated as bPWM providing the highest weed control. Overall mean WSP spot deposits ranged from 42.3 to 81.1 spots cm-2, compared to 14.0 to 47.0 spots cm-2 previously reported for similar spray conditions, with spot deposits attributed to negligible wind versus wind, respectively. Thus, the spray environment, particularly wind, exhibited effects on nozzle tip comparisons for foliar deposition and may offer some rationale for the conflicting published data beyond the examined treatments. Keywords: Application technology, Blended pulse-width modulation, Herbicide, Herbicide resistance, Nozzle, Spray deposition, Water-sensitive paper, Weed.

Developing the USDA ARS Spray Nozzle Models for Rotary Wing Applications

2017 ◽  
Vol 33 (5) ◽  
pp. 631-640
Author(s):  
W Clint Hoffmann ◽  
Bradley K Fritz
Keyword(s):  
Droplet Size ◽  
User Interfaces ◽  
Computational Models ◽  
Spray Deposition ◽  
Orientation Angle ◽  
Spray Drift ◽  
Product Label ◽  
Aerial Application ◽  
Nozzle Orifice ◽  
Rotary Wing

Abstract. Optimizing aerial spray applications requires proper setup of the sprayer system, particularly with respect to nozzle selection and operation, which significantly affects spray deposition, product efficacy, and spray drift. Droplet size from an aerial application is a function of the combination of nozzle type, nozzle orifice size, spray pressure, orientation angle, and airspeed of the aircraft. A set of computational models for 14 commonly-used aerial application nozzles were developed and released for use by applicators. These models allow applicators to determine the droplet size characteristics associated with their specific nozzle and operational setup, determining the proper combination of orifice, pressure, orientation, and airspeeds from 22 to 54 m/s (50 to 120 mph), which are commonly-associated with applications made from rotary wing aircraft (i.e., helicopters). Both spreadsheet and smartphone user interfaces are available for applicators to use to ensure that their application conforms to the legal droplet size requirements specified on an agrochemical product label. Keywords: Aerial application, Atomization, Droplet size, Droplet size models, Spray nozzles.

Characterization of Biological Pesticide Deliveries through Hydraulic Nozzles

2018 ◽  
Vol 61 (3) ◽  
pp. 897-908
Author(s):  
Liping Xiao ◽  
Heping Zhu ◽  
Matthew Wallhead ◽  
Leona Horst ◽  
Peter Ling ◽  
...  
Keyword(s):  
Droplet Size ◽  
Spray Deposition ◽  
Crop Protection ◽  
Droplet Size Distribution ◽  
Spray Parameters ◽  
Plant Leaves ◽  
Spray Pattern ◽  
Flow Capacity ◽  
Nozzle Type ◽  
Pattern Width

Abstract. Increased use of biopesticides has spurred demand for efficient and effective delivery systems. To this goal, laboratory tests were conducted to investigate six different classes of biopesticides discharged from five different types of flat-fan nozzles, each with three flow capacities. The biopesticide classes were horticultural oil insecticide (HOI), bacterial biofungicide (BBF), botanical extract bio-insecticide (BEBI), liquid fungal bio-insecticide (FBI-ES), wettable powder fungal bio-insecticide (FBI-WP), and mineral salt biofungicide (MSBF). Droplet size distribution, spray pattern width, spray deposition, and coverage on plant leaves and water-sensitive paper (WSP) were the spray parameters tested. These parameters varied greatly with biopesticide class, nozzle type, and nozzle flow capacity. The DV0.5 of the biopesticides ranged from 75 to 519 µm for 0.76 L min-1 nozzles, from 86 to 509 µm for 1.51 L min-1 nozzles, and from 99 to 622 µm for 2.25 L min-1 nozzles. The use of different biopesticides with the same nozzle significantly altered the spray pattern width. Compared to a water-only solution, the largest change of spray pattern width was 14.7% for the air-induction nozzle (AI11004) discharging FBI-ES. The amount of spray deposited on plant leaves for all tested biopesticides (except HOI) did not vary significantly with different nozzle types. However, the air-induction nozzles produced the most uneven spray deposition patterns. Therefore, to achieve optimal spray application efficiency and effectiveness for discharging specific classes of biopesticide, the choice of the proper nozzle type and flow capacity is critical. Keywords: Biopesticide, Crop protection, Deposition, Droplet size, Spray coverage.

Spray Deposition of Clopyralid on Honey Mesquite (Prosopis glandulosa)

1991 ◽  
Vol 5 (3) ◽  
pp. 499-503 ◽  
Author(s):  
Rodney W. Bovey ◽  
Raymond A. Stermer ◽  
Louis F. Bouse
Keyword(s):  
Gas Chromatography ◽  
Droplet Size ◽  
Laboratory Experiments ◽  
Spray Deposition ◽  
Prosopis Glandulosa ◽  
Spray Droplet ◽  
Spray Solution ◽  
Spray Volume ◽  
Spray Deposit ◽  
Honey Mesquite

Greenhouse and laboratory experiments were conducted to evaluate the influence of clopyralid formulation, spray droplet size, and spray volume on deposit of clopyralid on greenhouse-grown honey mesquite. The addition of surfactant WK at 0.5% (v/v) of the spray solution caused a twofold increase in deposition of spray of the monoethanolamine salt (MEA) of clopyralid but not the oleylamine salt (OLA). There were no differences in spray deposit between spray droplet size spectrums of 160 or 330 μm Dv.5or spray solution applications of 47 or 187 L ha-1. Dye and gas chromatography measurements of spray deposit of clopyralid compared favorably except where surfactant WK was used with the OLA formulation.

scholarly journals INFLUENCE OF DROPLET SIZE ON SPRAY DEPOSITION AND WEED CONTROL USING GLYPHOSATE

2021 ◽  
Vol 41 (4) ◽  
pp. 449-457
Author(s):  
Osmar G. T. M. Oliveira ◽  
Paulo R. M. Lopes ◽  
Carlos G. Raetano ◽  
Ronaldo C. Lima ◽  
Evandro P. Prado
Keyword(s):  
Weed Control ◽  
Droplet Size ◽  
Spray Deposition

scholarly journals Evaluation of electrostatic sprayers and foggers for the application of disinfectants in the era of SARS-CoV-2

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257434
Author(s):  
Joseph P. Wood ◽  
Matthew Magnuson ◽  
Abderrahmane Touati ◽  
Jerome Gilberry ◽  
Jonathan Sawyer ◽  
...  
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Active Ingredient ◽  
Spray Deposition ◽  
Droplet Size Distribution ◽  
Electrostatic Charge ◽  
Spray Parameters ◽  
Spray Process ◽  
Different Types ◽  
Median Diameter

Although research has shown that the COVID-19 disease is most likely caused by airborne transmission of the SARS-CoV-2 virus, disinfection of potentially contaminated surfaces is also recommended to limit the spread of the disease. Use of electrostatic sprayers (ESS) and foggers to rapidly apply disinfectants over large areas or to complex surfaces has emerged with the COVID-19 pandemic. ESSs are designed to impart an electrostatic charge to the spray droplets with the goal of increasing deposition of the droplets onto surfaces, thereby promoting more efficient use of the disinfectant. The purpose of this research was to evaluate several spray parameters for different types of sprayers and foggers, as they relate to the application of disinfectants. Some of the parameters evaluated included the spray droplet size distribution, the electrostatic charge, the ability of the spray to wrap around objects, and the loss of disinfectant chemical active ingredient due to the spray process. The results show that most of the devices evaluated for droplet size distribution had an average volume median diameter ≥ 40 microns, and that four out of the six ESS tested for charge/mass produced sprays of at least 0.1 mC/kg. A minimal wrap-around effect of the spray deposition onto a cylindrical object was observed. The loss of disinfectant active ingredient to the air due to spraying was minimal for the two disinfectants tested, and concurrently, the active ingredient concentrations of the liquid disinfectants sprayed and collected 3 feet (1 meter) away from the spray nozzle do not decrease.

DROPLET SIZE AND LEAF MORPHOLOGY EFFECTS ON PESTICIDE SPRAY DEPOSITION

2000 ◽  
Vol 43 (2) ◽  
pp. 255-259 ◽  
Author(s):  
D. B. Smith ◽  
S. D. Askew ◽  
W. H. Morris ◽  
D. R. Shaw ◽  
M. Boyette
Keyword(s):  
Droplet Size ◽  
Leaf Morphology ◽  
Spray Deposition
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