Search Results (43)

The multiscale interactive system composed of wind, leaves, and droplets serves as a critical dynamic unit in precision orchard spraying. Its coupling mechanisms fundamentally influence pesticide transport pathways, deposition patterns, and drift behavior within crop canopies, forming the foundational basis for achieving intelligent and site-specific spraying operations. This review systematically examines the synergistic dynamics across three hierarchical scales: Droplet–leaf surface wetting and adhesion at the microscale; leaf cluster motion responses at the mesoscale; and the modulation of airflow and spray plume diffusion by canopy architecture at the macroscale. Key variables affecting spray performance—such as wind speed and turbulence structure, leaf biomechanical properties, droplet size and electrostatic characteristics, and spatial canopy heterogeneity—are identified and analyzed. Furthermore, current advances in multiscale modeling approaches and their corresponding experimental validation techniques are critically evaluated, along with their practical boundaries of applicability. Results indicate that while substantial progress has been made at individual scales, significant bottlenecks remain in the integration of cross-scale models, real-time acquisition of critical parameters, and the establishment of high-fidelity experimental platforms. Future research should prioritize the development of unified coupling frameworks, the integration of physics-based and data-driven modeling strategies, and the deployment of multimodal sensing technologies for real-time intelligent spray decision-making. These efforts are expected to provide both theoretical foundations and technological support for advancing precision and intelligent orchard spraying systems. Full article

The removal of iron deposits on shipwreck surfaces by mechanical cleaning is labour-intensive work. This study develops an in situ gel and peeling cleaning method, utilising a carboxymethyl chitosan/tannic acid (CMCS/TA) colloidal solution spray on the surface of ferruginous deposits, promoting their removal by adhesion, chelation, and electrostatic bonding processes. The investigation confirmed that the CMTA-2 sample exhibited a sprayable viscosity of 263 mPa/s, the largest single removal thickness of 1.01 mm, a significant reduction in the fe/s atomic ratio by 2.53 units, and enhanced the deposit removal homogeneity. The field testing of the Nanhai I cultural relic showed a 14.37% reduction in iron concentration and a significant decrease in red colour (Δa* = 4.36). The synergistic mechanism involves TA chelating Fe²⁺/Fe³⁺ ions, while the CMCS gel network facilitates interfacial adhesion and mechanical peeling, hence promoting efficient and controllable cleaning. Full article

To address the technical problems of broad droplet size spectrum, insufficient atomization uniformity, and spray drift in plant protection unmanned aerial vehicle (UAV) applications, this study developed a novel two-stage aerial electrostatic spraying device based on the coupled mechanisms of hydraulic atomization and electrostatic induction, and, through the integration of three-dimensional numerical simulation and additive manufacturing technology, a new two-stage inductive charging device was designed on the basis of the traditional hydrodynamic nozzle structure, and a synergistic optimization study of the charging effect and atomization characteristics was carried out systematically. With the help of a charge ratio detection system and Malvern laser particle sizer, spray pressure (0.25–0.35 MPa), charging voltage (0–16 kV), and spray height (100–1000 mm) were selected as the key parameters, and the interaction mechanism of each parameter on the droplet charge ratio (C/m) and the particle size distribution (Dv50) was analyzed through the Box–Behnken response surface experimental design. The experimental data showed that when the charge voltage was increased to 12 kV, the droplet charge-to-mass ratio reached a peak value of 1.62 mC/kg (p < 0.01), which was 83.6% higher than that of the base condition; the concentration of the particle size distribution of the charged droplets was significantly improved; charged droplets exhibited a 23.6% reduction in Dv50 (p < 0.05) within the 0–200 mm core atomization zone below the nozzle, with the coefficient of variation of volume median diameter decreasing from 28.4% to 16.7%. This study confirms that the two-stage induction structure can effectively break through the charge saturation threshold of traditional electrostatic spraying, which provides a theoretical basis and technical support for the optimal design of electrostatic spraying systems for plant protection UAVs. This technology holds broad application prospects in agricultural settings such as orchards and farmlands. It can significantly enhance the targeted deposition efficiency of pesticides, reducing drift losses and chemical usage, thereby enabling agricultural enterprises to achieve practical economic benefits, including reduced operational costs, improved pest control efficacy, and minimized environmental pollution, while generating environmental benefits. Full article

As an innovative plant protection method in precision agriculture, electrostatic spray technology can increase the droplet coverage area by over 30% coMpared to conventional spraying. This technology not only achieves higher droplet deposition density and coverage but also enables water and pesticide savings while reducing environmental pollution. This study, combining theoretical analysis with experimental validation, reveals the critical role of electrode material selection in induction-based electrostatic spray systems. Theoretical analysis indicates that the Fermi level and work function of electrode materials fundamentally determine charge transfer efficiency, while corrosion resistance emerges as a key parameter affecting system durability. To elucidate the effects of different electrode materials on droplet charging, a coMparative study was conducted on nickel, copper, and brass electrodes in both pristine and moderately corroded states based on the corrosion classification standard, using a targeted mesh-based charge-to-mass measurement device. The results demonstrated that the nickel electrode achieved a peak charge-to-mass ratio of 1.92 mC/kg at 10 kV, which was 8.5% and 11.6% higher than copper (1.77 mC/kg) and brass (1.72 mC/kg), respectively. After corrosion, nickel exhibited the smallest reduction in the charge-to-mass ratio (19.2%), significantly outperforming copper (40.2%) and brass (21.6%). Droplet size analysis using a Malvern Panalytical Spraytec spray particle analyzer (measurement range: 0.1–2000 µm) further confirmed the atomization advantages of nickel electrodes. The volume median diameter (Dv50) of droplets produced by nickel was 4.2–8 μm and 6.8–12.3 um smaller than those from copper and brass electrodes, respectively. After corrosion, nickel showed a smaller increase in droplet size spectrum inhomogeneity (24.5%), which was lower than copper (30.4%) and brass (25.8%), indicating superior droplet uniformity. By establishing a multi-factor predictive model for spray droplet size after electrode corrosion, this study quantifies the correlation between electrode characteristics and spray performance metrics. It provides a theoretical basis for designing weather-resistant electrostatic spray systems suitable for agricultural pesticide application scenarios involving prolonged exposure to corrosive chemicals. This work offers significant technical support for sustainable crop protection strategies. Full article

This study evaluates the performance of a novel high-clearance air-assisted electrostatic sprayer designed for vineyards and investigates the impact of applied voltage on droplet deposition. This sprayer, which uses a new type of air-assisted electrostatic spray nozzle, could spray three rows of grapes at the same time, significantly improving work efficiency. Field test results show that the middle row of the high-clearance air-assisted electrostatic sprayer deposition effect was better than the left and right rows, and the minimum droplet deposition density inside the grape canopy was 26.4 deposits/cm². The droplet deposition effects of electrostatic spraying were effectively improved, and the average droplet deposition density of the canopy increased by 15.72%. Electrostatic spraying improves the deposition on the outer canopy but reduces deposition on the inner canopy, so electrostatic spraying reduces the penetration of droplets into the canopy. The sprayer’s design proves effective for large-scale operations, offering insights into electrostatic spray technology’s role in precision agriculture. Full article

For crop protection, electrostatic spraying technology significantly improves deposition uniformity and pesticide utilization through the “wraparound-adsorption” effect of charged droplets. However, existing electrostatic nozzles using hydraulic atomization suffer from low charge-to-mass ratios due to unclear principles for optimizing electrode parameters. To this end, this study designs and evaluates a novel air-assisted hydraulic-atomization hollow-cone electrostatic nozzle. First, the air-assisted hollow-cone nozzle was designed. High-speed imaging was then employed to obtain morphological parameters of the liquid film (length: 2.14 mm; width: 1.96 mm; and spray angle: 49.25°). Based on these parameters, an electric field simulation model of the electrostatic nozzle was established to analyze the influence of electrode parameters on the charging performance and identify the optimal parameter combination. Finally, feasibility and efficiency evaluation experiments were conducted on the designed electrostatic nozzle. The experimental results demonstrate that cross-sectional dimensions of the electrode exhibit a positive correlation with the surface charge density of the pesticide liquid film. In addition, optimal charging performance is obtained when the electrode plane coincides with the tangent plane of the liquid film leading edge. Based on these charging laws, the optimal electrode parameters were determined as follows: 2.0 × 2.0 mm cross-section with an electrode-to-nozzle tip distance of 3.8 mm. With these parameters, the nozzle achieved a droplet charge-to-mass ratio of 4.9 mC/kg at a charging voltage of 3.0 kV. These charged droplets achieved deposition coverages of 12.19%, 5.72%, and 5.91% on abaxial leaf surfaces in the upper, middle, and lower soybean canopies, respectively, which is a significant improvement in deposition uniformity. This study designed a novel air-assisted hollow-cone electrostatic nozzle, elucidated the optimization principles for annular induction electrodes, and achieved improved spraying performance. The findings contribute to enhanced pesticide application efficiency in crops, providing valuable theoretical guidance and technical references for electrostatic nozzle design and application. Full article

Electrostatic spraying systems can improve the pesticide application efficiency by enhancing droplet deposition and coverage within crop canopies. This study evaluated the droplet size spectra and charge-to-mass ratio (CMR) of five electrostatically charged hollow-cone nozzles and one flat-fan nozzle paired with an electrode. Each nozzle was mounted on a moving boom in a wind tunnel and operated with the electrode and voltage that produced the highest CMR. Their effects on the spray coverage and deposition inside boxwood shrubs at wind speeds of 0 and 2.24 m s⁻¹ were assessed. The nozzles operated with the optimized electrode had average improvements in the canopy deposition and canopy coverage of 1.33 µg cm⁻² and 4.4% at a wind speed of 0 m s⁻¹ and 0.26 µg cm⁻² and 0.9% at a wind speed of 2.24 m s⁻¹. The airborne drift measurements at various heights above the wind tunnel floor showed an average 0.50 µg cm⁻² reduction in the drift at 0.1 m, variable results at 0.35 m, and minimal changes at heights of 0.7 m and above at a downwind distance of 2 m. These findings highlighted the potential of optimized electrostatic spraying systems to enhance pesticide deposition inside the crop canopy under various wind speeds while reducing the spray drift potential. Full article

Electrostatic droplets can enhance deposition on target leaves. To comprehensively investigate the main factors affecting droplet adhesion and splashing after electrostatic droplet impact on pepper leaves, a specialized experimental platform was developed to capture the impact behavior of charged droplets on pepper leaves. The following four variables were examined: the applied voltage of the electrode ring, droplet size, impact velocity, and the relative distance from the impact point to the leaf tip (expressed as a percentage of the total leaf length). The results showed that all four factors had significant effects on droplet adhesion. The effect sizes (partial η²) of the four factors, in descending order, were impact velocity (0.935), applied voltage (0.907), impact position (0.895), and droplet size (0.505). Compared with non-electrostatic droplets, the increase in the maximum spreading factor of charged droplets was positively correlated with droplet size, impact velocity, and applied voltage but showed no significant correlation with the relative distance to the leaf tip. The critical velocity for splashing of electrostatic droplets decreased to a certain extent but increased with higher applied voltages. The influence of the four factors on droplet splashing decreases in the following order: impact velocity (odds ratio ≫ 1), charging voltage (odds ratio = 1.246), droplet size (odds ratio = 1.023), and impact position (odds ratio < 1). Among these, impact velocity has the most significant effect on splashing behavior. This study reveals the adhesion and splashing mechanisms of electrostatic droplets on flexible pepper leaves, providing theoretical support for the design of electrostatic spraying systems and the selection of operational parameters. The findings offer a scientific basis for optimizing droplet deposition, minimizing splash losses, and improving application efficiency in precision spraying. Full article

Air assistance and electrical charge transfer to droplets can optimize pesticide applications and reduce losses in sweet pepper cultivation. The objective of this study was to evaluate the effects of spray rate and pneumatic spraying with and without an electrostatic charge on spray deposition, spray coverage, and ground losses in sweet pepper crops. Four application techniques were employed: standard farmer hydraulics (SFH), reduced volume hydraulics (RVH), pneumatic with air and electrostatic assistance (PAEA), and pneumatic with air assistance (PAA). The effects of the application techniques on spray deposition varied as a function of plant height, canopy depth, and leaf surface. The SFH resulted in the greatest amounts of spray deposition on the adaxial leaf surface. In contrast, PAEA resulted in the greatest amounts of deposition on the abaxial leaves. The PAEA treatment improved spray coverage on abaxial leaves of the external canopy but did not improve spray coverage on the internal canopy. Compared to the SFH treatment, the 50% reduction in the spray rate of the RVH treatment decreased deposition and spray coverage. The pneumatic treatments, regardless of electrostatic charges, resulted in lower spray loss to the ground. Full article

The efficient hydrogenation of 1-butene is an industrially significant reaction for producing fuels and value-added chemicals. However, achieving high catalytic efficiency and stability remains challenging, particularly for cost-effective materials, such as Ni. In this study, we developed a porous Ni-coated Ni foam catalyst by electrostatic spray deposition to address these challenges. The catalyst exhibited a turnover frequency approximately 10 times higher than that of either porous Ni or Ni foam alone. This enhancement was attributed to the formation of interfacial active sites, which facilitated improved reactant adsorption and activation during hydrogenation. The electrostatic spray deposition technique ensured a uniform and controlled coating, enabling precise engineering of the catalyst structure and interface. The post-deposition heat treatment was further optimized to enhance structural integrity and catalytic performance. This study highlights the importance of interface engineering and structural optimization in catalyst design and provides valuable insights into the development of efficient Ni-based catalysts for industrial hydrogenation applications. These findings emphasize the potential of electrostatic spray deposition as a versatile method for fabricating advanced catalytic systems. Full article

Spraying is currently one of the main methods of pesticide application worldwide. It converts the pesticide solution into fine droplets through a sprayer, which then deposit onto target plants. Therefore, in the process of pesticide application, improving the effectiveness of spraying while minimizing or preventing crop damage has become a key issue. Combining the advantages of electrostatic spraying technology with the characteristics of ground boom sprayers, a contact-type electrostatic boom spraying system based on a rod–plate electrode structure was designed and tested on a self-propelled boom sprayer. The charging chamber was designed based on the characteristics of the rod–plate electrode and theoretical analysis. The reliability of the device was verified through COMSOL numerical simulations, charge-to-mass ratio, droplet size, and droplet size spectrum measurements, and a droplet size prediction model was established. The deposition characteristics in soybean fields were analyzed using the Box–Behnken experimental design method. The results showed that the rod–plate electrode structure demonstrated its superiority with a maximum spatial electric field of 2.31 × 10⁶ V/m. When the spray pressure was 0.3 MPa and the charging voltage was 8 kV, the droplet size decreased by 26.6%, and the charge-to-mass ratio reached 2.88 mC/kg. Field experiments showed that when the charging voltage was 8 kV, the spray pressure was 0.3 MPa, the traveling speed was 7 km/h, and the number of deposited droplets was 8517. This study provides some basis for the application of electrostatic spraying technology in large-scale field operations. Full article

In densely planted solar greenhouses, tomato crops face increasing challenges with pest and disease control due to high temperature and humidity conditions. The existing spraying equipment often suffers from low mechanization and inadequate foliar deposition coverage. This study presents the design of a vertical spray bar electrostatic sprayer, which combines a multi-nozzle vertical spray bar with electrostatic spraying technology, making it suitable for greenhouse applications. In order to obtain the best working parameters of the sprayer, the coverage rate of the front and back sides of the tomato leaves was taken as the performance target. Key influencing factors, including electrostatic voltage, spray pressure, and target distance, were investigated using a multi-factor response surface methodology. Field experiments were conducted in a greenhouse environment based on the optimized parameters to validate the performance. The results indicate that: (1) The factors influencing droplet adherence on the upper surface of tomato leaves ranked in the order of target distance, spray pressure, and electrostatic voltage, while for the underside, the order was electrostatic voltage, target distance, and spray pressure. (2) Under the conditions of electrostatic voltage of 10 kV, spray pressure of 0.7 MPa, and target distance of 35 cm, the sprayer achieves the optimal operation of leaf comprehensive coverage. (3) Compared to non-electrostatic spraying, the greenhouse electrostatic sprayer significantly improved the coverage on both sides of the leaves, enhancing pesticide utilization efficiency. This novel electrostatic sprayer meets the operational requirements for greenhouse crop protection in the Xinjiang region of China. Full article

Pesticide application development has grown exponentially in recent decades thanks to the implementation of new technologies and improved quality of spray input application. Electrostatic technology for increasing deposition has proven to be a suitable tool under specific study conditions, such as when working with very small droplet sizes, with air assistance, or typically in greenhouse environments. However, its effectiveness in hydraulic spraying, as well as its application from a commercial point of view in agriculture, is still challenging. The aim of this study was to evaluate the performance of this technology by implementing a modified lance on a small commercial knapsack sprayer, equipped with a hydraulic nozzle providing a range of droplet size values (Dv50) from 136 μm to 386 μm in the pressure range between 2 and 6 bar. This setup allowed operation under normal conditions (disconnected electrostatic system: NES) or with the connected electrostatic system (ES), with both configurations being tested in this study. Liquid distribution profiling as well as qualitative and quantitative evaluation of deposition were carried out both under laboratory conditions and in tomato crops under greenhouse conditions. The results showed no differences between the ES and NES in terms of flow rate (L min⁻¹) characterization or in the total accumulated volume collected with the vertical bench. The impact of the electrostatic system connection was clearly observed in laboratory trials, with total deposition increases of up to 66%. In field trials, this effect decreased in unexposed areas and in denser sections of the crop. However, the overall increase in deposition, mainly associated with the exposed side, continued to be significant. Full article

In order to investigate the effects of various factors (charging voltage, spray distance and spray pattern) on the deposition coverage of tomato leaves, the Box–Behnken surface response methodology was used to design an outdoor air-assisted electrostatic spraying experiment with three factors and three levels. The deposition coverage of tomato leaves in the upper, middle and lower layers was collected under different polarity charging voltages (0, +10 kV, −10 kV), spray distances (1, 3, 5 m) and spray patterns (ascending spray, descending spray, fixed height spray). Regression analysis and variance analysis were performed on the experimental data to determine the optimal working parameters. The results showed that (1) spray distance is the most important factor affecting the droplet coverage rate in the process of air-assisted electrostatic spraying; (2) the droplet coverage rate of air-assisted electrostatic spraying is optimal when the charging voltage polarity is negative voltage, the spray distance is 2.75 m, and the spray pattern is descending spray. The following conclusions were obtained. (1) In air-assisted electrostatic spraying, the distribution of air flow had the greatest effect on droplet deposition on tomato leaf surface. (2) Compared with air-assisted non-electrostatic spray, air-assisted electrostatic spray had a better deposition effect. Full article

Ti₃C₂T_x MXene, as a common two-dimensional material, has a wide range of applications in electrochemical energy storage. However, the surface forces of few-layer or monolayer Ti₃C₂T_x MXene lead to easy agglomeration, which hinders the demonstration of its performance due to the characteristics of layered materials. Herein, we report a facile method for preparing monolayer Ti₃C₂T_x MXene on nickel foam to achieve a self-supporting structure for supercapacitor electrodes under high electrostatic fields. Moreover, the specific capacitance varies with the deposition of different-concentration monolayer Ti₃C₂T_x MXene on nickel foam. As a result, Ti₃C₂T_x/NF has a high specific capacitance of 319 mF cm⁻² at 2 mA cm⁻² and an excellent long-term cycling stability of 94.4% after 7000 cycles. It was observed that the areal specific capacitance increases, whereas the mass specific capacitance decreases with the increasing loading mass. Attributable to the effect of the high electrostatic field, the self-supporting structure of the Ti₃C₂T_x/NF becomes denser as the concentration of the monolayer Ti₃C₂T_x MXene ink increases, ultimately affecting its electrochemical performance. This work provides a simple way to overcome the agglomeration problem of few-layer or monolayer MXene, then form a self-supporting electrode exhibiting excellent electrochemical performance. Full article