Uniform Spray Research Articles

Reprecipitation-mediated regulation on the surface architecture of uniform spray dried lactose microspheres

Lactose microspheres (LMs) are commonly used in the pharmaceutical field. Although the surface architecture of LMs directly correlates with the performance of the final products, surface manipulation remains challenging. In this study, uniform LMs were fabricated using template-assisted spray drying with polyethylene glycol 200 as the template. The influence of the solvent composition (methanol, ethanol, 1-butanol, and acetone, with and without added water) and post-treatment parameters (time and temperature) on the moisture content, particle morphology, surface architecture, and crystal polymorphism were investigated. The sample surfaces post-treated using methanol were covered with particulate crystals with a crystallinity of ∼88.3 %, whereas those treated using acetone were covered by coral-like crystals with a crystallinity of ∼80.6 %. This is attributed to the higher solubility of lactose in methanol than in acetone. Adding a small amount of water to the post-treatment solvent facilitated amorphous lactose reprecipitation, achieving a block-like crystal stacking surface with a more stable Lα∙H2O content (∼40.4 % w/w). Lα∙H2O enriched on the LM surfaces prevents water absorption during storage, thus maintaining their high dispersity, uniformity, and surface architecture. This study provides a promising strategy for tailoring the surface architecture of spherical crystalline lactose microspheres.

Investigation of fuel temperature and injection timing effects on ammonia direct injection in an optical engine

This work investigates the effects of fuel temperature and injection timing on ammonia direct injection in an optical engine using a multi-hole injector. Flash-boiling may occur over various engine-relevant conditions due to ammonia’s high vapor pressure. This phenomenon impacts spray characteristics and, in severe cases, facilitates cavitation inside the nozzle. Both fuel temperature and injection timing (i.e., ambient conditions during injection) impact the intensity of flash-boiling during fuel injection. Therefore, this work varies fuel temperature (from 320K to 388K) and injection timing (from −60CADaTDC (crank angle degrees after top dead center) to −6CADaTDC) to assess their impact on injection mass flux, discharge coefficients, and macroscopic spray characteristics using an ammonia injection pressure of 200bar. For this purpose, the injection mass is measured by analyzing exhaust gas compositions during engine operation with ammonia injections but without combustion. In addition, diffuse background illumination (DBI) images capture the liquid phase of the fuel spray to characterize spray behavior. The findings reveal that increasing fuel temperature decreases ammonia’s injection mass by up to 12.8% but has little impact on discharge coefficients for late injection timings and high in-cylinder pressures. However, discharge coefficients decrease by up to 17.4% (from 0.58 to 0.48) for early injection timings if fuel temperatures are high. The individual sprays of the 6-hole GDI injector may collapse into a uniform spray at high-density conditions without flash-boiling or under strongly flash-boiling conditions. The findings clarify the impact of ammonia’s high vapor pressure on injection mass and prove the relevance of different spray collapse mechanisms in ammonia direct injection engines.

Design and Testing of a Fruit Tree Variable Spray System Based on ExG-AABB

This paper addresses the issue of pesticide waste and low utilization rates resulting from traditional plant protection via spraying operations, which apply equal dosages to different targets or to different parts of the same target. To tackle this problem, we designed a variable fruit tree spraying system based on the ExG-AABB (excess green and axis-aligned bounding box) algorithm. We used a Kinect depth camera to capture information about the fruit tree canopy and constructed a spray flow model using pulse width modulation and variable spray control technology. Variable multi-nozzle spraying was guided by combining this canopy data. We evaluated the accuracy of each model in calculating canopy volume by comparing the coefficient of determination (R2) and root mean square error (RMSE) of the ExG-AABB with the slice convex hull method, voxel method, three-dimensional alpha-shape method, and QuickHull method. The ExG-AABB algorithm had the highest R2 value (0.9334) and the lowest RMSE value (0.0353 m3) among the five models, indicating that it most accurately reflects the true volume of the fruit tree canopy. This validates the effectiveness of the ExG-AABB algorithm in calculating canopy volume. We established a correlation model between canopy volume and spray volume, designed a canopy-adaptive layering method based on point cloud processing, and achieved precise calculation of nozzle flow. Comparative field experiments were conducted to analyze the spray coverage rate and observed flow, thereby evaluating the spraying effect of this variable spraying system. The experimental results showed that compared to conventional continuous spraying, this variable spraying system not only achieves more uniform spray coverage but also significantly reduces pesticide usage by 48.1%. Furthermore, through system optimization, the average coverage rate of the middle layer of the canopy decreased by 17.53%, effectively reducing the phenomenon of overlapping spraying from multiple nozzles and improving spraying efficiency.

Performance of Different Spray Nozzles in the Application of Defoliant on Cotton Plants (Gossypium hirsutum L.)

Defoliant spraying is an important link in the mechanized cotton harvest because adequate and uniform spraying can improve defoliation quality and reduce cotton trash content. In defoliant application, application volume and spraying technology are extremely important. In this study, the effectiveness of defoliant application to cotton plant that has come to harvest with two different application volumes and three different types of nozzles with a standard field crop sprayer was determined. Application rates were 250 and 400 L/ha and spraying nozzles were: (1) standard flat fan nozzle (TP8006), (2) air induction nozzle (AI 11002-VS) and (3) dual pattern nozzle (AI307003VP). A tracer (BSF) and defoliant were applied to mature cotton with approximately 60% open bolls and samplings for BSF deposition and spray coverage on cotton plant were done at two plant height (upper layer, lower layer) of plant. Before and after spraying, bolls open and leaves rate on cotton plants were calculated and filter papers were used to detect BSF deposition and water sensitive papers (WSP) were used to measure coverage rate of spraying methods used. Spectrofluorophotometer was used to detect the amount of tracer deposition on targets and an image process computer program was used to measure coverage rate on WSP. In analysis conclusions showed that air induction nozzle (AI 11002-VS), achieved better results than the dual pattern and standard flat fan nozzles in terms of higher depositions, coverages and leaf defoliations and boll opening rates. AI nozzles operating at 250 L/ha application rate provide the highest deposition and coverage rate on applications of defoliant, in addition, BSF as an indicator of the defoliant used reached on leaf beneath in merely this spray nozzle. After defoliation boll opining rate was 85-% on the 7th and 12th days after spraying and falling rate of leaves was 76-% at application rate of 250 L/ha with air induction (AI1102) nozzle.

Advancements in Sustainable Aviation Fuels: Impact of Nano-Additives and Ammonia-Based Strategies On Emissions

Abstract Our study investigates the impact of ammonia- and water-based nano-particulate additives on the combustion characteristics of Jet-A1 aviation fuel, using a 300-kW liquid swirl combustor. Experiments were conducted at two global equivalence ratios (Φ = 0.24 and Φ = 0.40), focusing on laminar flame speed (LFS) and flame properties through chemiluminescence imaging and modal analysis techniques. The primary objective was to understand how these nano-additives modulate flame dynamics and internal chemical reactions, alongside evaluating the environmental implications of combustion alterations. Results showed that integrating urea and water additives into the fuel matrix affected LFS, enhancing it at the lower equivalence ratio but having detrimental effects at the higher ratio. Modal analysis revealed a notable stabilizing influence on flame behavior, especially under leaner fuel conditions. The addition of water and urea influenced combustion chemistry and spray patterns, leading to more uniform sprays and more complete combustion. Chemiluminescence imaging demonstrated higher emission intensity of NH2* radicals compared to NH* radicals, varying with the global equivalence ratio. The data indicated a significant reduction in NOx emissions, particularly at lower equivalence ratios, accompanied by a slight increase in CO2 and CO emissions. This study highlights the potential of ammonia- and water-based nano-additives to enhance the combustion performance and environmental outcomes of Jet-A1 aviation fuel, with the trade-off of increased CO2 and CO emissions requiring further consideration.

Experimental Study on the Characteristics and High‐Temperature Heat Transfer of Secondary Cooling Nozzle for High‐Efficiency Slab Continuous Casting Process

In the continuous casting process, the heat transfer effect of secondary cooling plays an important role in the quality of the slab. The cooling intensity and cooling uniformity of the secondary cooling nozzle need more efficient spray cooling to achieve. Herein, the cold characteristics of different types of nozzles were compared. It is found that the second type of air mist nozzles have more uniform water density and striking force. On this basis, high‐temperature heat transfer experiments for casting billets were carried out to study the heat transfer coefficients of different air mist nozzles in the secondary cooling zone of continuous casting. It is found that the heat transfer coefficient increases as the distance of the temperature measurement point from the nozzle directly below increases. The heat transfer coefficients of the casting billet in both the jet and non‐jet zones are decreasing to varying degrees. When the temperature drops to 600 °C, the second type of air mist nozzle shows a faster temperature drop at the point of measurement, a smaller difference in time taken for temperature drop between jet and non‐jet zones, and faster and more uniform spraying, leading to a more significant trend of increasing heat transfer coefficient.

Research and application of surface spray anti-corrosion technology for coiled tubing in pressurized environment

In this study, the corrosion risk of coiled tubing under high pressure, high temperature and high sulfur conditions was investigated, and the protection solution was put forward. In this paper, spray paint is used to prevent corrosion of tubing, and the effects of high temperature desulfurization and nano super absorbent spraying agent are compared. The pressure jet spraying device is designed for uniform spraying during operation to improve corrosion resistance. Determine the best spraying position and monitoring point. The results show that nano-coating agent can prevent cracking and serious corrosion, and its application effect in oil wells meets the requirements. These findings support that anti-corrosion spraying technology on coiled tubing surface can effectively prevent tubing corrosion in high temperature, high pressure and corrosive environment.

High-speed multi-camera videogrammetric measurement of full-field 3D motion and deformation in full-scale crash testing of typical civil aircraft

Crashworthiness has been and will continue to be the main concern in aircraft design. Crash tests are essential approaches to investigate the crashworthiness of civil aircraft. Videogrammetric methods have been employed in crash tests to overcome the disadvantages of laborious, time-consuming measurement data collection using contact sensors. However, previous methods using a single pair of cameras still face challenges in large-scale applications due to the inherent contradiction between measurement range and accuracy. In this paper, a videogrammetric method using four high-speed cameras is proposed to measure the full-field three-dimensional (3D) dynamic deformation for evaluating the impact response characteristics of the full-scale crash test aircraft. Increasing the number of high-speed cameras not only can enhance the resolution and then measurement accuracy of object, but also expands the measurement range significantly. To ensure the performance of digital image correlation (DIC) used for large-scale measurement range, a speckle pattern optimization design and fabrication method is presented to generate the random speckle with uniform spraying size and density. A global calibration method based on the high-precision total station is proposed to unify the data of different stereovision subsystems. The implementation of the proposed method is illustrated through a 6.0 m/s full-scale crash test using a civil aircraft approximately 24 m in length. The impact velocity, full-field displacement and strain of the fuselage structure are measured. The results show that the test data are complete and reliable. After the vertical crash at 5.71 m/s, the lower structure of the cabin floor is seriously deformed, and the upper structure of the fuselage in the central wing area is obviously deformed due to the inertia effect of the wing. The stiffness difference of the different fuselage segments results in significant differences in dynamic response. The higher the stiffness is, the smaller the deformation. This work may provide some valuable technical insights that could support the crashworthy design, verification, and certification of civil aircraft.

VACUUM SYSTEM FOR COATING PARTS OF ROCKET AND SPACE EQUIPMENT

A vertical type vacuum plant was created for applying coatings using the ion-plasma deposition method to the inner surface of hollow products with a diameter of up to 200 mm and a length of up to 1000 mm. The plant includes: a vacuum chamber with a vacuum system, an evaporator with a magnetic system, a power supply and control system, a cooling system. Radial evaporation cathode of tubular shape with controlled arc is used. Inside the cathode is a magnetic system that controls the movement of cathode spots on its surface. Permanent magnets create arched magnetic fields that hold the position of the discharge track in the tangential direction. The trajectory of the movement of the cathode spots has the form of an ellipse stretched along the cathode. For uniform spraying of the cathode surface, the track moves in two directions: around the circumference of the cathode surface and along its length. A mechanism for moving the magnetic system is mounted on the cover of the vacuum chamber. The product to be coated is mounted inside the vacuum chamber in a vertical position thanks to the removable top cover. The necessary rarefaction of the atmosphere (vacuum) is achieved with the help of two vacuum pumps. Coating materials are traditional Сr and Ni-Cr alloys. A feature of the coating structure is presented: the formation of a combination of solid condensed and soft droplet phases. The droplet phase is a part of the evaporator material with several times lower hardness compared to the nitrided condensed phase. The distribution of the soft phase in a strong coating prevents its brittleness, which is important for thick coatings. The disadvantage of the vacuum-arc deposition process is the heating of the part to a temperature of 380-450 °C. To exclude the softening of the main metal of the combustion chamber and nozzle, it is recommended to use bronze alloys with a recrystallization temperature of at least 500 °C.

Effects of header design on thermal characteristics of multi-nozzle steam spraying

The distribution header of small-scale steam systems, commonly employed in household items like steam cleaners, is pivotal for dictating the spray characteristics of the steam generated. For uniform spray performance across multiple outlets, it's imperative to discern the design factors influencing this outcome. We numerically assessed the flow characteristics of steam in a spraying system with three nozzle outlets and scrutinized the impact of header design parameters on uniformity. Through a multiphase numerical model, numerical simulations were conducted. Our analysis revealed that decreasing the diameter of the three outlets promoted a more even mass flow rate of the sprayed steam from each outlet, having a minimal effect on temperature consistency. In contrast, enlarging the tapering angle of the header improved temperature uniformity up to 62.5 % but negatively influenced the uniformity of the steam spray amount when outlet diameters were consistent. Notably, when the combined area of the outlets was increased, there was a decline of up to 85 % in the uniformity of the discharged steam mass among the outlets with an increased tapering. This research offers insights that are anticipated to inform future studies and advancements in steam spraying system optimization, enhancing performance and efficiency for applications such as steam cleaning and sterilization processes.

UIO-66-NH2/polydopamine double coating modification on cotton fabric for sound absorption and noise reduction

Noise pollution greatly harms social and economic development and human health. Textiles are used frequently and are essential to the interior's sound absorption and noise reduction. In this study, a polydopamine layer with damping, noise reduction, and adhesion functions was first finished onto cotton fabrics using a deposition method, followed by uniform spraying of Metal-organic framework particles with porous sound absorption structures using an ultrasonic precision sprayer. The successful adhesion of dopamine and UIO-66-NH2 on the fiber surface was verified using characterization methods, and the parameters affecting the acoustic properties of the fabric were explored. The results show that MOFs and polydopamine improve fabrics' absorption and reduction of acoustic waves. This work confirms the successful application of the double coating of UIO-66-NH2 and dopamine in fabric sound absorption. It provides a method for designing and preparing acoustic protection textiles.

A smart roof that transforms raindrops into agricultural spraying.

We present a smart roof that makes fragmented droplets from the impact of raindrops on superhydrophobic meshes and utilizes the droplets for agricultural spraying. This facile method transforms raindrops or waterdrops into uniform microdroplets, which can both reduce crop lodging induced by heavy rainfall, and realize uniform spraying of pesticides.

Optimizing Mist-Based Ablution: A Comprehensive Study of Water Distribution and Conservation Using Watercolour Visualization and Thermal Imaging Techniques

Conducting ablution constitutes a prerequisite for Muslims prior to engaging in prayer. This ritualistic practice involves the cleansing and wiping of specific body parts, including the hands, face, arms up to the elbows, head, and feet. Ensuring comprehensive water coverage of the aforementioned areas is a crucial criterion during ablution. However, excessive water consumption often occurs when Muslims perform ablution to achieve full coverage. Consequently, a more ecologically sustainable approach to ablution is necessary to minimize water wastage. A proposed water mist spray device aims to optimize water usage while adhering to the Islamic jurisprudence requirements of complete water coverage on ablution parts.To assess water coverage using the mist spray, an evenness distribution profile is employed through atomized mist colorization on paper and thermal imaging of ablution parts. An appropriate spray nozzle is chosen based on an analysis of spray distribution and coverage patterns on the target surface, utilizing image processing techniques. The proposed methodology involves mixing water with red watercolour and manually pumping it through the selected nozzle using an off-the-shelf water sprayer, thereby atomizing the coloured water to stain white paper. Subsequently, the paper is converted into a digital image and analysed using ImageJ software to determine the mist spray coverage percentage, spatial spread at various distances, and the extraction of stain and droplet sizes. This technique is applied to different types and sizes of spraynozzles to identify the most suitable nozzle for the prototype.The findings demonstrate that nozzles with smaller exit holes and higher water pressure yield more extensive spray coverage on the target surface. Upon selecting the appropriate nozzle, a Portable Ablution Mist Spray Device prototype is employed to evaluate water coverage for the ablution body parts. Thermal images of the ablution parts are captured before and after the ritual, with the temperature differences being analysed. The thermal images reveal a comprehensive and uniform spray distribution on the ablution body parts, accompanied by a temperature difference ranging from 0.9°C to 3.8°C among various participants.

Uniform Droplet Spraying of Magnesium Alloys: Modeling of Apollonian Fractal Structures on Micrograph Sections

A variety of advanced manufacturing processes have been developed based on the concept of rapid solidification processing (RSP), such as uniform droplet spraying (UDS) for the additive manufacturing of metals and alloys. This article introduces a morphological simulation of fractal dendric structures deposited by UDS of magnesium (Mg) alloys on two-dimensional (2D) planar sections. The fractal structure evolution is modeled as Apollonian packs of generalized ellipsoidal domains growing out of nuclei and dendrite arm fragments. The model employs descriptions of the dynamic thermal field based on superposed Green’s/Rosenthal functions with source images for initial/boundary effects, along with alloy phase diagrams and the classical solidification theory for nucleation and fragmentation rates. The initiation of grains is followed by their free and constrained growth by adjacent domains, represented via potential fields of level-set methods, for the effective mapping of the solidified topology and its metrics (grain size and fractal dimension of densely packed domains). The model is validated by comparing modeling results against micrographs of three UDS-deposited Mg–Zn–Y alloys. The further evolution of this real-time computational model and its application as a process observer for feedback control in 3D printing, as well as for off-line material design and optimization, is discussed.

Sublethal Effects of Neonicotinoid Insecticides on the Development, Body Weight and Economic Characteristics of Silkworm.

Silkworm Bombyx mori (L.) (Lepidoptera: Bombycidae) is a critical insect for silk producers, but the inappropriate application of insecticides negatively affects the physiology and behavior of silkworms. This study found that the effects of neonicotinoid insecticides applied using two spraying methods on the growth and development of silkworms were different: the median lethal concentration (LC50) values of two pesticides applied using the leaf-dipping method were 0.33 and 0.83 mg L-1 and those of two pesticides applied using the quantitative spraying method were 0.91 and 1.23 mg kg-1. The concentration of pesticides on the mulberry leaves did not decrease after their application using the quantitative spraying method, and a uniform spraying density was observed after the mulberry leaves were air-dried (no liquid) under realistic conditions. We then treated silkworms with the quantitative spraying method and leaf-dipping method. The treatment of silkworm larvae with imidacloprid and thiamethoxam at sublethal concentrations significantly prolonged the development time and significantly decreased the weight and pupation rate, as well as economic indicators of enamel layers and sputum production. Thiamethoxam treatment significantly increased the activities of carboxylesterase (CarE) and glutathione-S-transferase (GST). The activity of CarE and GST increased, decreased, and then increased, and the highest activity was detected on the 10th and 12th days. Thiamethoxam exposure significantly elevated the transcription levels of CarE-11, GSTe3 and GSTz2 and induced DNA damage in hemocytes. This study confirmed that the quantitative spray method is more stable than the leaf-dipping method. Moreover, imidacloprid and thiamethoxam treatment affected the economy and indexes of silkworms and induced changes in detoxification enzymes and DNA damage in silkworms. These results provide a basis for understanding the mechanism of the sublethal effects of insecticides on silkworms.

Influence of Different Levels of NAA and 2, 4, 5-T on Fruit Drop, Fruiting, Fruit Retention, Growth and Yield of Indian Ber (Zizyphus mauritiana Lamk.)

The experiment was carried out at Horticulture Garden, Department of Fruit Science, Chandra Shekhar Azad University of Agriculture & Technology, Kanpur (U.P.) during the November 2020- March 2021 and November 2021- March 2022. Sixteen treatments viz. four levels of NAA (0, 20, 30 and 40 ppm) and 2,4,5-T (0, 10, 20 and 30ppm) were studies in a Factorial Completely Randomized Design with three replications. Spraying was done on eleventh November, 2020 in first year and fifteenth November, 2021 in second year at fruit setting stage (Pea Stage) with fine nozzle sprayer in each treatment to give uniform spray on all over the treatment of ber plant. Application of (NAA@40 ppm and 2,4,5-T@30 ppm) significantly maximized initial fruit set (162.00 and 163.66), maximum fruit retention (20.39 and 20.43 percent) and maximum initial fruit set percentage (79.60 and 79.56 per cent). The length and width of fruit was significantly (5.35 and 4.99 cm) and (4.24 and 4.27 cm) respectively increased by application same concentration mention above. The maximum (36.62 and 36.82 g) fruit weight and physical properties of fruits like volume (36.57 and 36.42 cc) recorded under treatment (NAA@40ppm and 2,4,5-T@30ppm). The minimum stone length (0.88 and 0.87 cm), minimum stone diameter (0.88 and 0.87 cm), minimum stone weight (0.65 and 0.66 gm) and specific gravity (0.94 and 0.94 g cc-1) significantly found under (NAA@40 ppm and 2,4,5-T@30 ppm). The yield of ber was significantly increased (39.53 and 40.49) kg per plant, yield per hectare (121.30 and 121.33quintal) with treatment combination (NAA@40ppm and 2,4,5-T@30ppm) both the years of experiment.

Matching the Liquid Atomization Model to Experimental Data Obtained from Selected Nozzles

The spraying procedure is one of the most difficult operations in agricultural production. Achieving the desired effectiveness of the procedure is dependent on obtaining an appropriate level and uniformity of liquid distribution. The aim of this paper was to present a liquid decomposition model generated on the basis of experimental data. The tests were carried out on a test stand, which consisted of a container with nozzles and a grooved table. The experiments were carried out with the use of selected standard, anti-drift, and air-induction single-stream nozzles at constant liquid pressure. The optimization process was carried out in Microsoft Excel Solver. Furthermore, in order to compare the data generated by the model with the data from the virtual boom, we applied an analysis of correlation and linear regression in the Statistica 13.1 software. Based on the results obtained, it can be concluded that the model is a good fit to the experimental data (R2 > 0.95). The model, which was generated on the basis of experimental data, will facilitate control of the operation and degree of wear of nozzles, which will contribute to ensuring uniform spraying.

Influence of the downwash airflow in Hexacopter Drone on the spray distribution pattern of boom sprayer

The spray characteristics of drone sprayers are significantly influenced by the downwash airflow produced by Drone multi-rotors. The present study aimed to study the influence of downwash airflow and the operational parameters of Drone sprayer, viz., flight height, travel speed, rotor configuration, payload and wind velocity on the spray distribution pattern for boom sprayer attachment to Drone. The boom type sprayer consisted of four numbers of flat fan nozzles placed at three different spacing viz., 30, 45 and 60 cm between each nozzle. The spray distribution pattern of the Hexacopter Drone was studied at three different operating pressures, viz., 3.0, 4.0 and 5.0 kg cm-2. A spray patternator of 5 m x 5 m was developed per the Bureau of Indian Standards (BIS) standard to study the spray uniformity of volume distribution pattern. The best spray uniformity was found as 0.37 % CV value at 60 cm nozzle spacing and 4 kg cm-2 operating pressure. The optimised parameters viz., 60 cm of nozzle spacing and 4 kg cm-2 operating pressure, the influence of downwash airflow on the spray volume distribution of hexacopter Drone with boom spray attachment were studied. The Drone hovered at three different heights, viz., 1.0, 2.0 and 3.0 m from the top of the patternator and spray operating pressure was maintained at 4 kg cm-2. It was observed that less volume of spray was collected at the middle portion when the Unmanned Aerial Vehicle (UAV) was hovered at 1.0 m height due to the direct impact of downwash airflow of rotors. The uniform spray volume distribution pattern was observed when Drone hovered from 1.0 m to 3.0 m height. A round vertex pattern of spray pattern was generated with boom type nozzles configuration due to the direct impact of downwash airflow of rotors. This study will be helpful in the configuration of nozzles attached to the drone sprayers, optimization of spray operational parameters, and revealing spray volume distribution pattern.

Spray coverage profiles from pecan air-blast sprayers, with a radial air-flow and a volute-generated focused air-flow, as affected by forward speed and application volume

Pecan (Carya illinoinensis) is an important specialty crop in the U.S.A., but yield is limited by several diseases and pests. In mature-tree pecan orchards, large air-blast sprayers are commonly used to apply the pesticides to control these diseases and pests. The spray coverage, deposition and profiles are poorly defined under the range of application scenarios, limiting the recommendations that can be provided to growers to maximize control while minimizing input costs. To explore effects of sprayer setting parameters such as travel speed and spray volume rate on spray coverage on tall targets we set up a system (a simple vertical patternator) using a 19-m-tall pole with cards attached at eight height levels from 5 to 19 m above ground, allowing to determine the vertical distribution pattern of two air-blast sprayers with different air discharge systems. Spray was applied with a standard radial-flow air-blast sprayer during six treatments being combinations of two travel speeds: 2.4 and 3.2 km/h, and three spray volume rates: 470, 940 and 1970 L/ha, as well as with a focused air-flow system (a volute) sprayer during four treatments being combinations of two travel speeds: 2.4 and 3.2 km/h, and two spray volume rates: 470 and 940 L/ha. Results show that using a standard radial air-flow sprayer, application volume affected coverage at heights ≤17 m (higher volumes resulting in more coverage). Higher speed using a standard radial air-flow sprayer resulted in greater spray coverage, but was inconsistent with the focused air-flow system. Using a focused air-flow system more spray coverage occurred at >17 m compared to a standard radial air-flow sprayer. Spray coverage profiles affirmed the rapid decline in coverage with height using a standard radial air-flow sprayer. The results may help guide decisions on volute use, spray volume, and spray partitioning to different parts of the canopy to improve spray profile characteristics for applying more uniform spray coverage to mature pecan tree canopies.

A Turbidity Module to Measure Spray Mixture Concentration for Premixing In-Line Injection System

Highlights A turbidity sensor module was investigated to monitor concentrations of pesticide mixtures in real time. A flow-through measurement platform was built to calibrate the turbidity sensor and determine its accuracy. Optimal location of the turbidity sensor was determined for monitoring in-line mixture concentrations. Spray mixture uniformity reached acceptable level for the premixing in-line injection system. Abstract. Monitoring mixture concentrations for precision pesticide spray systems in real time can assure the desired amount of chemicals distributed uniformly to target areas. An in-line turbidity sensor module was investigated to monitor concentrations of spray mixtures produced with a premixing in-line injection system developed for precision variable-rate orchard sprayers. The turbidity sensor was calibrated with simulated pesticides at concentrations ranging from 0% to 30.0%. A cubic polynomial regression model was established for the relationship between sensor output voltages and mixture concentrations. Sensors were mounted at three in-line locations to detect the mixture uniformity differences in the premixing in-line injection system. The module was found to have adequate precision and accuracy to measure concentrations of spray mixtures with simulated pesticides. Relative errors of the sensor were less than 4.70% and the sensor accuracy did not vary with mixture flow rates. Mounting the turbidity sensor downstream of the buffer tank in the premixing in-line injection system would be the optimal location to monitor spray mixture uniformity for variable-rate spray applications. At this location, the relative errors of measured mixture concentrations were between 0.12% and 3.70% which agreed with previous manual measurements. Therefore, there would be a great potential to integrate the in-line turbidity sensor into the variable-rate and even conventional constant-rate sprayers to achieve uniform spray applications in the target field. Keywords: Agitation, Mixture uniformity, Pesticide concentration, Sensor calibration, Variable-rate sprayer.