scholarly journals Influence of Droplet Sizes on the Percentage of Airborne Spray Droplets in Oil-based Aerosols

1988 ◽  
Vol 13 (2) ◽  
pp. 253-260 ◽  
Author(s):  
Shigenori TSUDA ◽  
Isao NISHIBE ◽  
Goro SHINJO
Keyword(s):  
Spray Droplets ◽  
Droplet Sizes

Droplet size impact on lactofen and acifluorfen efficacy for Palmer amaranth (Amaranthus palmeri) control

2019 ◽  
Vol 34 (3) ◽  
pp. 416-423
Author(s):  
Lucas X. Franca ◽  
Darrin M. Dodds ◽  
Thomas R. Butts ◽  
Greg R. Kruger ◽  
Daniel B. Reynolds ◽  
...  
Keyword(s):  
Droplet Size ◽  
Pulse Width Modulation ◽  
Effective Means ◽  
Cost Effective ◽  
Palmer Amaranth ◽  
Target Movement ◽  
Spray Droplet ◽  
Spray Droplets ◽  
Droplet Sizes ◽  
Biomass Reduction

AbstractHerbicide applications performed with pulse width modulation (PWM) sprayers to deliver specific spray droplet sizes could maintain product efficacy, minimize potential off-target movement, and increase flexibility in field operations. Given the continuous expansion of herbicide-resistant Palmer amaranth populations across the southern and midwestern United States, efficacious and cost-effective means of application are needed to maximize Palmer amaranth control. Experiments were conducted in two locations in Mississippi (2016, 2017, and 2018) and one location in Nebraska (2016 and 2017) for a total of 7 site-years. The objective of this study was to evaluate the influence of a range of spray droplet sizes [150 (Fine) to 900 μm (Ultra Coarse)] on lactofen and acifluorfen efficacy for Palmer amaranth control. The results of this research indicated that spray droplet size did not influence lactofen efficacy on Palmer amaranth. Palmer amaranth control and percent dry-biomass reduction remained consistent with lactofen applied within the aforementioned droplet size range. Therefore, larger spray droplets should be used as part of a drift mitigation approach. In contrast, acifluorfen application with 300-μm (Medium) spray droplets provided the greatest Palmer amaranth control. Although percent biomass reduction was numerically greater with 300-μm (Medium) droplets, results did not differ with respect to spray droplet size, possibly as a result of initial plant injury, causing weight loss, followed by regrowth. Overall, 900-μm (Ultra Coarse) droplets could be used effectively without compromising lactofen efficacy on Palmer amaranth, and 300-μm (Medium) droplets should be used to achieve maximum Palmer amaranth control with acifluorfen.

Investigating the Wettability of Rapeseed Leaves

2021 ◽  
Vol 37 (3) ◽  
pp. 399-409
Author(s):  
Yong He ◽  
Jianjian Wu ◽  
Shupei Xiao ◽  
Hui Fang ◽  
Qishuai Zheng
Keyword(s):  
Surface Tension ◽  
Free Energy ◽  
Significant Influence ◽  
Leaf Surface ◽  
Contact Angles ◽  
List Type ◽  
Factors Affecting ◽  
Spray Droplets ◽  
Droplet Sizes ◽  
Leaf Wettability

HighlightsContact angles of spray droplets were positively correlated with their surface tension.Wettability of rape leaves was generally poor for most pesticides.Surface structure and free energy determine the hydrophobicity of rape leaves.The size of the spray droplets had no significant influence on rape leaf wettability.Abstract. In order to improve the deposition and adherence of spray droplets on leaf surfaces, the wettability of rapeseed leaves was investigated. We explored the effect of different pesticides and test surfaces on droplet contact angles, and analyzed the effects of leaf surface properties, droplet sizes and the addition of organosilicone adjuvant on wettability. The results indicated that contact angles of different liquids were positively correlated with their surface tension for rapeseed leaves. The wettability of rapeseed leaves was generally poor using different pesticides, but was highest for a fungicide mixture of difenoconazole and propiconazole. The hydrophobicity of rapeseed leaves is largely determined by the complex microstructure and the low surface free energy of the leaves. The size of the spray droplets had no significant influence on the wettability. Moreover, the addition of an organosilicone adjuvant significantly reduced the surface tension of all spray droplets, with the best result for a 50% procymidone solution. In conclusion, the factors affecting rapeseed leaf surface wettability should be considered comprehensively before selecting the appropriate pesticide, so as to improve its utilization rates. Keywords: Contact angle, Leaf surface, Pesticide application, Spray droplet.

Effect of glyphosate spray droplets on leaf cytology in velvetleaf (Abutilon theophrasti)

Weed Science ◽  
2004 ◽  
Vol 52 (2) ◽  
pp. 302-309 ◽  
Author(s):  
Jan S. Ryerse ◽  
Roger A. Downer ◽  
R. Douglas Sammons ◽  
Paul C. C. Feng
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Structural Change ◽  
Abutilon Theophrasti ◽  
Leaf Epidermis ◽  
Contact Site ◽  
Cellular Changes ◽  
Spray Droplets ◽  
Droplet Sizes ◽  
Scanning Electron

Leaf cytoarchitecture was evaluated by light microscopy and scanning electron microscopy, and cell viability was monitored by fluorescence after treatment of velvetleaf with defined concentrations and droplet sizes of formulated glyphosate and blended tallowamine surfactant. In response to droplets of formulated glyphosate larger than in field sprays but useful for studying structural change, we observe that the leaf epidermis thins and flattens within 1.5 h, the epidermal, mesophyll, and vascular cells at the contact site exhibit localized cytolysis by 6 h, and cytolysis and pycnosis remain restricted to the contact site at 24 h. Using endogeneous fluorescence as a marker for nonviable cells, it was determined that cellular changes are directly correlated with droplet size and that the changes are minimal after exposure to spray sizes and concentrations of formulated glyphosate and blended tallowamine typically used in the field. The results show that, at field use concentrations, the effect of formulated glyphosate and blended tallowamine on leaf cytoarchitecture is modest and localized but sufficient to allow herbicide entry.

Investigation of Optimum Applied Voltage, Liquid Flow Pressure, and Spraying Height for Pesticide Application by Induction Charging

2019 ◽  
Vol 35 (5) ◽  
pp. 795-804 ◽  
Author(s):  
Samuel Appah ◽  
Weidong Jia ◽  
Mingxiong Ou ◽  
Pei Wang ◽  
Chen Gong
Keyword(s):  
Flow Rate ◽  
Liquid Flow ◽  
Applied Voltage ◽  
Liquid Flow Rate ◽  
Plant Protection ◽  
Pesticide Application ◽  
Optimum Parameters ◽  
Spray Droplets ◽  
Droplet Sizes ◽  
Flow Pressure

Abstract. Superposition of charges to pesticide spray droplets by electrostatic induction principle plays an important role in plant protection. It influences spray droplets characteristics, deposition and wraparound effect on leaf surfaces. Hence, an adoption of optimum parameters combination will improve spraying effectiveness to reduce pesticide wastage and environmental pollution. This article investigated the effect of 0-12 kV applied voltages, 2-4 bar liquid flow pressures, and 20-60 cm spraying height regimes on spray chargeability, droplet sizes, spray swath, and droplets deposition while all other parameters were kept constant. The combined parameters of 12 kV applied voltage, 4 bar liquid flow pressure, and 60 cm spraying height produced maximum charged spray swath (1.98 m) and fine particulate droplet sizes (48.91 µm). However, applied voltage of 12 kV, liquid flow pressure of 4 bar at spraying height of 20 cm yielded maximum chargeability of -1.95×10-3 mC kg-1. Since spraying height influences the extent of pesticide spray coverage, a boom height of 60 cm is suitable for deposition in electrostatic pesticide application at 12 kV charging voltage and 4 bar liquid flow rate. The operation of combined optimum parameters took reference from a uniform plant height surface during spraying. Hitherto, the study would help farmers to select suitable electrostatic spraying parameters for pesticide application in plant protection. Keywords: Applied voltage, Charge-mass ratio, Droplet sizes, Liquid flow rate, Spray pressure, Spray swath.

scholarly journals Spray nozzle selection contributes to improved postemergence herbicide crabgrass control in turfgrass

2021 ◽  
Author(s):  
Edward Nangle ◽  
Zane Raudenbush ◽  
Tyler Morris ◽  
Michael Fidanza
Keyword(s):  
Perennial Ryegrass ◽  
Cultural Practices ◽  
Kentucky Bluegrass ◽  
Effective Control ◽  
Future Research ◽  
Herbicide Application ◽  
Spray Droplet ◽  
Spray Droplets ◽  
Droplet Sizes ◽  
Turfgrass Management

For optimum postemergence crabgrass (Digitaria spp.) control, a single quinclorac herbicide application could be properly timed and delivered with spray nozzles that produce spray droplets ranging from very coarse (401 - 500 µm) to medium (226 - 325 µm) in size to maximize target coverage and minimize the potential for drift.  Crabgrass is an invasive annual grass weed of cool-season turfgrass maintain as lawns, golf courses, and sports pitches.  Postemergence herbicide applications for crabgrass control in turfgrass swards often rely on repeated applications for effective control.  Optimizing postemergence crabgrass applications can reduce pesticide inputs and contribute to sustainable turfgrass management practices.  Two field studies evaluating crabgrass control were conducted in 2020 in a mixed stand of Kentucky bluegrass (Poa pratensis L.) with perennial ryegrass (Lolium perenne L.) in Ohio (USA) and in perennial ryegrass in Pennsylvania (USA).  Both sites have histories of natural crabgrass [Digitaria sanguinalis (L.) Scop.] infestation.  A postemergence herbicide, quinclorac, was applied at the product label rate and tank-mixed with methylated seed oil at the crabgrass plant stage of three leaf to one tiller.  Different spray nozzles were selected to deliver the following spray droplet classifications and sizes at 275 kPa:  Delavan Raindrop 1/4, ultra coarse (> 650 µm); TurfJet 1/4TTJO4, extremely coarse (501 - 650 µm); Air Induction AA8004 or XRTeeJet 8015, very coarse (401 - 500 µm); XR TeeJet 8008 or GreenLeaf TDAD04, coarse (326 - 400 µm); XR TeeJet 8004, medium (226 - 325 µm); and XRTeeJet 8003 fine (145 - 225 µm).  Crabgrass pressure was low in Ohio, and herbicide efficacy at 60 days after treatment was considered acceptable when applied from all spray nozzles that produced pray droplet sizes ranging from ultra coarse to fine.  Crabgrass pressure was severe in Pennsylvania, and herbicide efficacy at 60 DAT was considered marginally acceptable when applied from spray nozzles that produced spray droplet sizes ranging from very coarse to medium.  Future research should consider cultural practices that would be complimentary to postemergence herbicide applications with the goal to further reduce pesticide use and minimize any potential environmental impacts related to spray drift.   Highlights - In turfgrass sites with low crabgrass pressure, one postemergence application of quinclorac herbicide could potentially achieve acceptable control with spray nozzles that produce spray droplets ranging from ultra coarse (> 650 µm) to fine (145 - 225 µm). - In turfgrass sites with heavy crabgrass population and pressure, one postemergence application of quinclorac herbicide is best optimized with spray nozzles that produce spray droplets ranging from very coarse (401 - 500 µm) to medium (226 - 325 µm). - Overall, turfgrass management practitioners should avoid using spray nozzles that produce a hollow cone spray pattern with ultra coarse (> 650 µm) spray droplets which can result in poor or irregular herbicide coverage, or fine (145 - 225 µm) spray droplets which are subject to potential drift and possible negative off-target effects. - Overall, in an effort to reduce herbicide use for postemergence crabgrass control, a single quinclorac herbicide application could be properly timed and optimized with nozzles that produce spray droplets ranging from very coarse (401 - 500 µm) to medium (226 - 325 µm) in size, however, future research should consider cultural practices that would further optimize and also reduce herbicide applications.

Effect of pH and NH4NO3 as a Spray Additive on Penetration of NAA Through Isolated Tomato Fruit Cuticle

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 550a-550 ◽  
Author(s):  
Royal G. Fader ◽  
Martin J. Bukovac
Keyword(s):  
Direct Measurement ◽  
Sodium Citrate ◽  
Tomato Fruit ◽  
Initial Slope ◽  
Control Effect ◽  
Solution Ph ◽  
Ph Change ◽  
Effect Of Ph ◽  
Spray Droplets ◽  
Partition Behavior

We have reported that NH4NO3 (AN, 8 mM, pH 4.2), applied as simulated spray droplets, enhanced penetration of 14C-NAA through isolated leaf and fruit cuticles. One explanation for this response is that AN depresses NAA (pKa= 4.2) dissociation, increasing the nondissociated moiety, which penetrates more readily than the anion (NAA'). Direct measurement of AN (concn. 0-800 mM) effect on NAA (215 μM) dissociation as indexed by change in solution pH revealed no significant effect, with a pH change from 4.19 to 4.05. This change is not sufficient to account for the observed enhancement. When 14C-NAA, buffered (20 mM sodium citrate) at pH 3.2, 4.2, 5.2, 6.2, was partitioned against chloroform, there was a marked increase in NAA partitioning into chloroform as pH was decreased. AN (8 mM) did not alter this partition behavior, also indicating no effect on NAA dissociation. However, in cuticle penetration studies, using a finite dose system with 14C-NAA buffered at pH 3.2, 4.2, 5.2, 6.2, and in the presence and absence of 8 mM AN, there was no marked or consistent pH or AN (-70 to + 232 % of no AN control) effect on penetration as indexed by initial slope (4-12 h) or penetration after 120 h. The possible effects of AN and buffer on penetration of 14C-NAA from the droplet deposit will be discussed.

scholarly journals Influence of Atomization Nozzles and Spraying Intervals on Growth, Biomass Yield, and Nutrient Uptake of Butter-Head Lettuce under Aeroponics System

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 97
Author(s):  
Mazhar H. Tunio ◽  
Jianmin Gao ◽  
Imran A. Lakhiar ◽  
Kashif A. Solangi ◽  
Waqar A. Qureshi ◽  
...  
Keyword(s):  
Root Growth ◽  
Nutrient Uptake ◽  
Nutrient Solution ◽  
Biomass Yield ◽  
Chemical Properties ◽  
Cultivated Plants ◽  
Growth Ratio ◽  
Shoot Ratio ◽  
Droplet Sizes ◽  
Root To Shoot Ratio

The atomized nutrient solution droplet sizes and spraying intervals can impact the chemical properties of the nutrient solution, biomass yield, root-to-shoot ratio and nutrient uptake of aeroponically cultivated plants. In this study, four different nozzles having droplet sizes N1 = 11.24, N2 = 26.35, N3 = 17.38 and N4 = 4.89 µm were selected and misted at three nutrient solution spraying intervals of 30, 45 and 60 min, with a 5 min spraying time. The measured parameters were power of hydrogen (pH) and electrical conductivity (EC) values of the nutrient solution, shoot and root growth, ratio of roots to shoots (fresh and dry), biomass yield and nutrient uptake. The results indicated that the N1 presented significantly lower changes in chemical properties than those of N2, N3 and N4, resulting in stable lateral root growth and increased biomass yield. Also, the root-to-shoot ratio significantly increased with increasing spraying interval using N1 and N4 nozzles. The N1 nozzle also revealed a significant effect on the phosphorous, potassium and magnesium uptake by the plants misted at proposed nutrient solution spraying intervals. However, the ultrasonic nozzle showed a nonsignificant effect on all measured parameters with respect to spraying intervals. In the last, this research experiment validates the applicability of air-assisted nozzle (N1) misting at a 30-min spraying interval and 5 min of spraying time for the cultivation of butter-head lettuce in aeroponic systems.

scholarly journals Cavitation patterns in high-pressure homogenization nozzles with cylindrical orifices: Influence of mixing stream in Simultaneous Homogenization and Mixing

2021 ◽  
Author(s):  
V. Gall ◽  
E. Rütten ◽  
H. P. Karbstein
Keyword(s):  
High Pressure ◽  
Process Design ◽  
High Speed ◽  
State Of The Art ◽  
Back Pressure ◽  
High Pressure Homogenization ◽  
Unit Operation ◽  
Mixing Chamber ◽  
Cavitation Intensity ◽  
Droplet Sizes

AbstractHigh-pressure homogenization is the state of the art to produce high-quality emulsions with droplet sizes in the submicron range. In simultaneous homogenization and mixing (SHM), an additional mixing stream is inserted into a modified homogenization nozzle in order to create synergies between the unit operation homogenization and mixing. In this work, the influence of the mixing stream on cavitation patterns after a cylindrical orifice is investigated. Shadow-graphic images of the cavitation patterns were taken using a high-speed camera and an optically accessible mixing chamber. Results show that adding the mixing stream can contribute to coalescence of cavitation bubbles. Choked cavitation was observed at higher cavitation numbers σ with increasing mixing stream. The influence of the mixing stream became more significant at a higher orifice to outlet ratio, where a hydraulic flip was also observed at higher σ. The decrease of cavitation intensity with increasing back-pressure was found to be identical with conventional high-pressure homogenization. In the future, the results can be taken into account in the SHM process design to improve the efficiency of droplet break-up by preventing cavitation or at least hydraulic flip.

scholarly journals Impact of Type of Sugar Beet Pectin–Sodium Caseinate Interaction on Emulsion Properties at pH 4.5 and pH 7

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 631
Author(s):  
Zhang Juyang ◽  
Bettina Wolf
Keyword(s):  
Sugar Beet ◽  
Storage Period ◽  
Small Deformation ◽  
Sodium Caseinate ◽  
Ph Adjustment ◽  
Potential Value ◽  
Emulsifier System ◽  
Oil In Water ◽  
Droplet Sizes ◽  
The Mean

Equal parts of sugar beet pectin and sodium caseinate were interacted through electrostatic attraction, enzymatic crosslinking, and the Maillard reaction to prepare three oil-in-water emulsifier systems. Oil-in-water emulsions (10%) were processed via high shear overhead mixing at the natural pH of the emulsifier systems, followed by pH adjustment to pH 4.5 and pH 7. The emulsions were stable against coalescence, except for a slight increase in the mean droplet size for the enzymatic cross-liked emulsion at pH 4.5 over a 14-day storage period. This emulsion also showed the lowest absolute zeta (ζ)-potential value of near 30 mV. The Maillard interaction emulsifier system resulted in larger droplet sizes compared to the other two emulsifier systems. Small deformation oscillatory shear rheology assessment of the emulsion cream phases revealed an impact of the emulsifier system design at pH 4.5.

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