Download or read book The Impact of Spray Adjuvants on Solution Physical Properties and Spray Droplet Size written by Bradley K. Fritz and published by . This book was released on 2018 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past several years, numerous anecdotes from aerial applicators have surfaced concerning observations of increased numbers of fine droplets seen in the applied spray clouds, often associated with tank mixtures that contain crop-oil concentrates (COCs) and foliar fertilizers (FFs). Efforts were made herein to correlate surface tension and viscosity to spray droplet size under a variety of aerial application conditions, but these efforts were unsuccessful. In addition, spray mixtures were examined to compare relative evaporation rates. Researchers are encouraged to actively pursue this line of work. The addition of several adjuvants and FFs were found to significantly affect spray droplet size, so applicators should pay careful attention to spray tank composition when making aerial spray applications.

Download or read book Effects of Adjuvants and Dynamic Surface Tension on Spray Properties Under Simulated Aerial Conditions written by WR. Dexter and published by . This book was released on 1998 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The literature on the effects of active ingredients, adjuvants and surface active agents on the droplet size of agricultural sprays is reviewed. The effects of various agricultural adjuvants on the droplet size distributions of a herbicide sprayed in a wind tunnel simulating an aerial application were determined using a Malvern laser diffraction instrument. All adjuvants caused a decrease in droplet size, which varied with adjuvant type and concentration. Measurements of equilibrium surface tension, dynamic surface tension at 20 ms, density, and viscosity were recorded. Droplet size did not correlate linearly with equilibrium surface tension: only at the lowest surface tensions was any significant decrease in droplet size observed. Droplet size correlated better with dynamic surface tension for each adjuvant over most of the surface tension range, but with different slopes for each adjuvant. At high concentrations of surfactant, bubbles of air were observed within captured droplets and the size distribution became bimodal.

Download or read book Effects of Spray Adjuvants on Spray Droplet Size from a Rotary Atomizer written by Chenghai Yang and published by . This book was released on 2016 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rotary atomizers are used in a number of aerial applications, such as forest pest spraying and mosquito control sprays. These types of atomizers have a rotating cage at speeds of 2,000 to 10,000 revolutions per minute (rpm) through which a spray is emitted and atomized. Many applicators routinely add spray adjuvants to change the droplet size, reduce drift potential, or to reduce evaporative effects of a particular spray solution; therefore, six commonly used classes of spray adjuvants were evaluated to determine their effects on droplet size. If an applicator's only concern was minimizing spray drift, the applicator could choose a polymer or high surfactant oil concentrate for helicopter speeds and a polymer for fixed-wing applications. For applicators working under hot, dry conditions where evaporation is a concern, choosing an oil-based adjuvant to help get better coverage by creating smaller droplets that do not evaporate would be recommended. Understanding the role the different adjuvant types play in the final droplet size of the spray is key to successfully setting up and making applications with rotary atomizers.

Download or read book Adjuvants for Agrichemicals written by Chester L. Foy and published by CRC Press. This book was released on 2018-05-04 with total page 763 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on a conference, this book is intended to promote a better understanding of the effects of adjuvants on pesticide penetration, translocation, photodegradation and stability, spray deposition and dissipation, and the fate of herbicides in the environment.

Download or read book Effects of Formulated Glyphosate and Adjuvant Tank Mixes on Atomization from Aerial Application Flat Fan Nozzles written by W. Clint Hoffmann and published by . This book was released on 2013 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study was designed to determine if the present USDA-ARS spray-nozzle models, which were based on spray solutions of water plus non-ionic surfactant, could be used to estimate spray droplet-size data for different spray formulations through use of experimentally determined correction factors. Twelve spray-solution treatments were evaluated, ten of which contained a formulated glyphosate product and nine of these contained an additional tank-mix adjuvant. Droplet-size testing was conducted across multiple operational points (nozzle-orifice size, nozzle orientation, spray pressure, and airspeed), in a high-speed wind tunnel, which corresponds to the response surface experimental model used to develop the present spray-nozzle models. The hypothesis that the different treatment solutions would respond linearly across a range of operational parameters and that a correction factor from relative to water plus non-ionic surfactant solution was proven false. When compared to water or the water plus non-ionic surfactant, the changes in atomization across the operation spectrum of the nozzle were not consistent and varied by formulation. Attempts to apply regression fits for a correction factor based on solution physical properties were not successful. With the formulated glyphosate tank mix used, none of the adjuvants tested, except the polymer, showed significant changes in droplet size under the high air shear regime. Whereas there is likely a need to develop formulated product-specific atomization models, the further addition of adjuvants do not significantly change the atomization characteristics, and, as such, should not require a unique spray-nozzle model.

Download or read book The Effect of Adjuvants Pesticide Formulation and Spray Nozzle Tips on Spray Droplet Size written by Kelli L. Nelms and published by . This book was released on 2009 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many factors, including adjuvants, pesticide formulations, and nozzle tips, affect spray droplet size. It is important to understand these factors as spray droplet size affects both drift and efficacy of pesticides, which is a main concern with pesticide application. A laser particle analyzer was used to determine the spray droplet size and distributions of a range of formulations sprayed through several types of nozzle tips. Nozzles included were extended range flat fan sizes 11003 and 11005 (Spraying Systems XR), air induction flat fan sizes 11005 and 11004 (AI), air induction extended range flat fan size 11005 (AIXR), preorifice flat fan size 11005 (TT), and a second preorifice flat fan size 2.5 (TF). Several deposition/retention adjuvants were studied, including Array, Interlock, In-Place, and Thrust. Another study looked at diflufenzopyr + dicamba (Status, BASF) in combination with several adjuvants. Also, three fungicides were evaluated at differing spray volumes. Results indicated that the droplet size of some nozzle tips is more affected than others by changes in the contents of the spray solution.

Download or read book The Effect of Adjuvants at High Spray Pressures for Aerial Applications written by W. Clint Hoffmann and published by . This book was released on 2016 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Controlling droplet size is a critical part of making any successful agrochemical spray application. This is particularly true for higher-speed aerial applications where secondary atomization from air shear becomes the most dominant factor driving spray droplet size. Previous research has shown that higher spray pressures can result in larger droplet-sized sprays by increasing the exit velocity of the spray liquid from the nozzles, which in turn decreases the differential velocity between the spray liquid and surrounding airstream, reducing secondary breakup. This work explores the effects of higher-than-normal spray pressures on two typical aerial application nozzles in the presence of a formulated herbicide spray solution, with and without additional adjuvants. Generally, the spray solution effects followed trends seen in previous studies, with crop oil-containing adjuvants resulting in the largest droplet-sized sprays and the silicones and polymers the smallest. Increasing spray pressure increased droplet size across all combinations of nozzle, airspeed, and spray solution, without exception. The most promising results from this work showed that for typical high-end application airspeeds, increasing spray pressure from the lowest to highest pressures tested generally resulted in spray classifications increasing at least one size coarser. The results from this work demonstrate that larger, faster-flying agricultural aircraft can adopt current methods, with potentially minor equipment adjustments, to generate medium and larger spray qualities and to allow for more efficient applications while meeting agrochemical product label requirements.

Download or read book Effects of Air Speed and Liquid Temperature on Droplet Size written by W. Clint Hoffmann and published by . This book was released on 2011 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advancements in both application hardware (e.g., nozzles and spray assist devices) and spray property modification products have led to a number of products that are specifically designed to maximize the on-target deposition and minimize off-target movement of spray droplets. Testing protocols are being developed to objectively measure spray drift reduction from a wide range of drift reduction technologies (DRTs) including spray nozzles, sprayer modifications, spray delivery assistance, spray property modifiers (adjuvants), and/or landscape modifications. Using a DRT evaluation protocol, the objectives of this work were to study the effects of different air speeds on droplet size from different spray nozzles and spray solutions and to further evaluate the effects of differences in liquid and air temperature on droplet size at the different air speeds tested. Measured spray droplet size was significantly affected by changes in airspeed with the DV0.5 increasing by ~30-100 ?m and the percent of spray volume less than 200 ?m decreasing by 50 % or more as the tunnel airspeed was increased from 0.5 to 6.7 m/s (1 to 15 miles per hour), depending on the spray solution, spray nozzle, and air speed. The data also showed a lesser influence of temperature differential between the spray solution and ambient air, with the differences seen most likely resulting from changes in spray solution physical properties with the changes in liquid temperature. Most importantly, this study demonstrated that a reference nozzle evaluated under the same conditions resulted in the reduction in driftable fines while the DRT remained constant across all conditions tested.

Download or read book Adjuvant Effects on Spray Characteristics and Drift Potential written by PCH Miller and published by . This book was released on 2001 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper describes studies that were conducted to investigate the effects of different surfactant and emulsion adjuvant chemistries and formulations on spray characteristics and drift potential of a commercial herbicide. Previous research has shown that surfactant, emulsion, and polymer adjuvants can affect the formation of sprays and liquid distribution patterns when atomized through flat fan nozzles. The present research involved the application of various different tank mix-adjuvant combinations through flat fan, disc-core, and air induction nozzles. The sprays were characterized using spark photography, droplet size analysis, liquid patternation, and driftability measurements in a wind tunnel. Atomization was related to the physical properties of the tank mixes and sheet breakup mechanisms. The results will help in the development of ASTM test guidelines for spray characterization and drift research, and provide valuable information for applicators to consider when selecting tank mix-nozzle combinations for the application of agricultural chemicals.

Download or read book Adjuvants and Agrochemicals written by Paul N. P. Chow and published by CRC Press. This book was released on 2018-01-18 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies of Adjuvants involve many scientific fields from basic research of the chemistry, through investigations into physiological effects and environmental impact, to mixture formulation and field use. These important areas are illustrated in these two volumes, which are contributions from the First International Symposium on Adjuvants for Agrochemicals, held in Brandon, Manitoba on August 5 to 7, 1986. A total of 200 participants from 19 countries met to discuss their common interest in adjuvant science, technology, and application. It is the editors hope that these volumes will stimulate interest in and promote a better understanding of the chemical, physiological, and agronomic aspects of adjuvants as they relate agrochemicals. In addition, the revisedAdjuvants for Agrochemicals: A Selected Bibliography of World Literature in the English Language will be a valuable resource for agricultural researchers and other users. We hope that adjuvant research will lead to even safer, more efficient, and more economical use of chemicals in agriculture and forestry.

Download or read book Physico Chemical Properties In Flight Evaporation and Spread of Spray Droplets Containing Pesticide Adjuvants written by RA. Downer and published by . This book was released on 1993 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: In-flight evaporation, droplet spread on water sensitive paper, equilibrium surface tension, and dynamic surface tension were measured for each of 12 adjuvants mixed with water. The correlation between the physico-chemical properties and droplet spread was determined. The results indicated that the adjuvants had significant and varied effects upon the parameters that were measured. Speculative rankings were derived for (A) evaporation rates and (B) spreading potentials. The rankings were compared with manufacturer's claims for the adjuvants and the results are discussed in terms of the benefits to be derived from using these products in pesticide applications.

Download or read book Modeling the Spray Atomization of Emulsion Embedded Agricultural Solutions written by De-Wei Yin and published by . This book was released on 2010 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: A typical agricultural chemical spray process involves atomizing a liquid stream of diluted pesticide solution through hydraulic spray nozzles that inherently produce a wide spectrum of spray droplet sizes. Finer droplets have higher potential for off-target movement or drift, which is of concern due to its potential impact on neighboring crops and livestock, sensitive ecological resources, and human health. Research by the Spray Drift Task Force and others has demonstrated that, although spray nozzle selection and application parameters are the key factors to produce the desired droplet size spectrum, the physical properties of the spray solution have significant effects on the droplet size distribution for various kinds of nozzles. One of these properties of many spray fluids is the inclusion of an oil phase in the form of an emulsion. The effect of oil-in-water emulsions on the spray droplet size distribution has been demonstrated by previous work. However, the mechanisms of this effect are largely unknown. In this study, a method to model this effect was proposed. A characteristic dimensionless number for connecting the bulk spray properties and the microscopic emulsion droplet properties was defined as the ratio between the emulsion recovery time and the spray atomization time. This study will help in the design of agricultural spray nozzles and the optimization of anti-drift spray additives.

Download or read book Pesticide Spray Droplet Adhesion Modeling written by JA. Zabkiewicz and published by . This book was released on 2001 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spray droplet adhesion is a consequence of dynamic interactions of formulants within the spray droplet during flight and on impact, physical properties of the droplet (size and velocity), leaf surface morphology and leaf orientation. The objective of this study was to improve on a universal adhesion model incorporating the above factors. The previous spray droplet adhesion model has been extended to include droplet size (ranging from 180 ?m to 1000 ?m) and droplet velocity (0.63 ms-1 to 2.82 ms-1 at impact), and made more robust by increasing the number of formulations (dynamic surface tension of droplets at impact range from 20.7 to 72 mN m-1), the types of leaf surfaces (20% acetone contact angles on the leaf surfaces range from 61° to 124°), and the number of droplet impact angles (leaf angles from horizontal to 67.5°). In this study, contact angles using 20% acetone:water accounted for 95% of the differences between the leaf surfaces studied compared to 76% previously observed with water only. The present universal model explains 74% of the deviance. The current model's capabilities and limitations are discussed in relation to the physical parameters measured and observed.

Download or read book Impact of Adjuvants on Droplet Spreading and Droplet Deposit Area After Spray Application written by Peter Baur and published by . This book was released on 2008 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of adjuvants on spreading of small droplets after spray application and of larger drops with volumes in the microliter range was studied. The characterization of spreading as affected by adjuvants is done often with lab tests on artificial surfaces. In these tests much larger drops in the microliter range are used and plant factors such as the presence of hairs or crystalline waxes and spray related factors such as rapid evaporation, a different drop size magnitude, a drop size distribution in reality, and effects of adjuvants on drop size are not considered. For a set of test compounds from different chemical classes we evaluated stepwise the approximation to real systems with plant surfaces representing the major surface features. With larger drops of 10 and 20 μl we obtained a surprisingly good correlation of spreading on Parafilm® M and the mature leaves of Chlorophytum, tomato, rape, and corn. With good wetters better spreading was observed on leaves than on Parafilm M. The correlation of spread diameters with real spray (flat fan nozzle, 300 l/ha) on an easily wettable plant and drops on Parafilm M was very good as well though with the best spreaders the gravimetric momentum on spreading and longer times for evaporation overestimated spreading of the larger droplets on Parafilm M. If the mean spread diameters of real spray was plotted vs. the logtransformed spread diameter on Parafilm M a linear correlation was obtained (r2=0.92).

Download or read book Spray Adjuvant Effects on Droplet Size Spectra Measured by Three Laser Based Systems in a High Speed Wind Tunnel written by J. B. Ross and published by . This book was released on 2008 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spray droplet size has long been recognized as the most important variable that aerial applicators can influence to mitigate spray drift from the application site. There are several different technologies that are used by researchers to measure droplet size from spray nozzles. The objective of these studies was to determine the influence of eight spray adjuvants on the droplet size spectrum produced by two nozzles in a high-speed wind tunnel when characterized using three different droplet size measurement systems. The adjuvant, nozzles, and airspeeds used in these studies are commonly used by aerial applicators. Three droplet sizing systems (Malvern laser diffraction, PMS optical array probe, and LaVision laser imaging) were simultaneously operated to measure the spray droplet size spectra for each adjuvant, airspeed, and nozzle combination. Two spray nozzles (a D6-46 nozzle and a D2 straight stream nozzle) were evaluated in a high-speed wind tunnel at airspeeds of 45 and 58 m/sec. There were significant differences in the droplet size spectra produced by the eight spray adjuvants tested. There were also significant differences between the droplet size values reported by the three measurement systems (Malvern, LaVision, and PMS) evaluated; however, there was considerable agreement trendwise. In general, the Malvern reported smaller spray droplet size spectra values than the LaVision, while the PMS system generally reported the largest spray droplet size spectra values. These tests are the first reported studies where all three droplet sizing systems were operated simultaneously.

Download or read book Atomization and Sprays written by Arthur H. Lefebvre and published by CRC Press. This book was released on 2017-03-27 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second edition of this long-time bestseller provides a framework for designing and understanding sprays for a wide array of engineering applications. The text contains correlations and design tools that can be easily understood and used in relating the design of atomizers to the resulting spray behavior. Written to be accessible to readers with a modest technical background, the emphasis is on application rather than in-depth theory. Numerous examples are provided to serve as starting points for using the information in the book. Overall, this is a thoroughly updated edition that still retains the practical focus and readability of the original work by Arthur Lefebvre.

Download or read book Physiology of Herbicide Action written by Malcolm Devine and published by Prentice Hall. This book was released on 1993 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: An introduction to herbicide action; Reaching the target; Oxigen toxicity and herbicidal action; Microtubule disruptors; Herbicide effects on lipid synthesis; Nucleic acid and protein synthesis inhibitors; Inhibition of amino acid biosysnthesis; Herbicides with auxin activity; Other sites of herbicide action; Secondary physiological effects of herbicides; Herbicide interactions with herbicides, synergists, and safeners; Naturally occurring chemicals as herbicides.