Deposition Coverage Research Articles

Effect of the Drone and Knapsack Sprayed Herbicides on the Plant Phytotoxicity and Chlorophyll Content in Rabi Groundnut

Conventional method of herbicide spray application using a knapsack sprayer is cost-effective, easy to operate but leads to inaccurate application of the chemicals, low spray uniformity, unnecessary deposition and non-uniform coverage. In this context, “Unmanned aerial vehicles (UAVs), or aerial drones, are being utilized to decrease the herbicide wastage and increase the efficacy compared to traditional practice. A two year field experiment was conducted with drone at RARS, Research Farm, Palem, Nagarkurnool, Telangana during rabi 2022-23, 2023-24.The model of UAV (drone) used in the bioefficacy and drift studies was battery motive AGRICOPTER AG 365 with UIN UA00132S1EX. Imazethapyr 3.75% + Propaquizafop 2.5% ME (Ready mix) herbicide was sprayed with 25 and 40 L ha-1 of spray volume with flat fan XR11002VP nozzle and flight height was maintained at 2 and 2.5m and knapsack sprayer with 500 L ha-1 of spray volume was taken to study the effect of the drone sprayed herbicides versus conventional spraying practices on plant phytotoxic and chlorophyll content of the leaves and results had shown a non significant effect on chlorophyll content and phytotoxicity.

Role of secondary char on the fuel properties and pyrolysis behaviors of hydrochars: Effect of temperature and liquid-solid ratio

Hydrothermal carbonization (HTC) is widely recognized as a promising approach for enhancing the fuel properties of agricultural waste. This study investigated the HTC characteristics of corn stalks, focusing on the effect of secondary char (SC) on the fuel properties and pyrolysis behaviors of hydrochars at different temperature and liquid-solid ratio (LSR). Results showed that lower LSR increased the carbon content and higher heating value of hydrochars. Higher temperature strengthened the effect of LSR. At 240 °C, hydrochar yield decreased from 58.56 % to 45.59 % as the LSR increased. The higher LSR enhanced hydrolysis and promoted the transfer of organic components to aqueous phase, thereby facilitating SC formation with a content as high as 12.10 %. The increase in SC was accompanied by larger carbon microspheres and greater deposition coverage, resulting in reduced specific surface area and elevated oxygen-containing functional groups. The covering of SC strengthened the pyrolysis-like reaction of primary char (PC) during HTC (limited by contact with water). These changes influenced subsequent pyrolysis behavior, with PC tending to produce phenols at low LSR but aromatic hydrocarbons at high LSR. This work could enhance the understanding of SC and provide a practical approach combining HTC and extraction to regulate bio-oil preparation by pyrolysis.

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.

A new method for estimating nanoparticle deposition coverage from a set of weak-contrast SEM images

Imaging nanomaterials in hybrid systems is critical to understanding the structure and functionality of these systems. However, current technologies such as scanning electron microscopy (SEM) may obtain high resolution/contrast images at the cost of damaging or contaminating the sample. For example, to prevent the charging of organic substrate/matrix, a very thin layer of metal is coated on the surface, which will permanently contaminate the sample and eliminate the possibility of reusing it for following processes. Conversely, examining the sample without any modifications, in pursuit of high-fidelity digital images of its unperturbed state, can come at the cost of low-quality images that are challenging to process. Here, a solution is proposed for the case where no brightness threshold is available to reliably judge whether a region is covered with nanomaterials. The method examines local brightness variability to detect nanomaterial deposits. Very good agreement with manually obtained values of the coverage is observed, and a strong case is made for the method's automatability. Although the developed methodology is showcased in the context of SEM images of Polydimethylsiloxane (PDMS) substrates on which silicone dioxide (SiO2) nanoparticles are assembled, the underlying concepts may be extended to situations where straightforward brightness thresholding is not viable.

Sonochemical deposition of gold nano-shells on suspended polymeric spheres

Metal nanoparticles have drawn great interest due to their unique properties for applications in the fields of catalysis, biomedicine and environmental science depending on the architecture of the metal nanoparticle composites. Amongst different designing routes, the chemical template deposition offers great flexibility in terms of the template selection and interfacial interactions, giving rise to controllable designs. In order to control over nanoparticle size distribution and deposition efficiency, a sonochemical approach has been systematically followed in this study. Key parameters of the ultrasound-assisted deposition procedures during the seeding step to synthesise gold nanoparticle-coated poly(styrene) beads were investigated. The impact of the solution pH and the ultrasonic frequency on the template deposition was examined at 139, 300, 500 and 1000 kHz. The results, monitored by transmission electron spectroscopic imaging, show that the highest gold deposition was achieved at 300 kHz, revealing the mechanistic details of the nucleation-crystal growth behaviour as a function of ultrasonic frequency and reaction time. In addition, the concentration ratio between gold ions and poly(styrene) beads was varied. The highest deposition coverage and smallest particle size were reached at 0.05 mM and 2.5 mg, respectively. The proposed mechanism of the MNPs formation and deposition behaviour were then discussed based on the tested parameters.

Extraction of crop canopy features and decision-making for variable spraying based on unmanned aerial vehicle LiDAR data

Implementation of precision agriculture aerial applications using unmanned aerial vehicles (UAVs) represents a pivotal technological aspect in precision agriculture. However, current UAV applications are still far from realizing true precision variable spraying. The use of UAVs to analyze and model crop growth, pest and disease conditions, and other pertinent information to enable targeted precision spraying poses a formidable challenge. Herein, a UAV variable-rate spray system with adaptive flow control based on crop canopy morphology was developed using a UAV equipped with a light detection and ranging (LiDAR) sensor to support precision spraying of cotton. Point cloud data captured by the LiDAR sensor initially undergo processing using the simple morphological filter (SMRF) algorithm and feature extraction function. Subsequently, cotton canopy volumes measured by the alpha shape algorithm, convex hull by slices shape algorithm, and voxel-based method were compared with manual measurements with coefficient of determination R2 values of 0.89, 0.78, and 0.82, respectively. The results of the validation experiments denote that the cotton canopy volume obtained using the alpha shape algorithm is in good agreement with that obtained using manual measurements; thus, this algorithm is employed for volume calculations in this design. Models were constructed to relate UAV flight parameters, cotton canopy volume, and spraying parameters to the duty cycle of variable control signals, which enabled the UAV to adjust the flow rate in real time to match the cotton canopy structure. In addition, a polygonal prescription map decoding algorithm based on the cotton canopy morphology was introduced. This algorithm is used for real-time decoding of prescription maps and extraction of flow, latitude, and longitude information. Finally, field experiments were conducted, and the results indicate that the UAV variable-rate spray system designed in this study exhibits biological efficacy (effective application thresholds provided by the pesticide manufacturer) comparable to that of the constant-rate spray system at a lower application rate. Furthermore, it exhibited superior spray deposition efficiency and coverage compared with the constant-rate spray system. Notably, the use of the variable-rate spray system in cotton crops resulted in a 43.37% reduction in spray volume while maintaining high application quality, providing an opportunity for pesticide and labor cost savings.

Design of inductive electrostatic boom spray system based on embedded closed electrode structure and droplet distribution test in soybean field.

The large water demand, insufficient deposition on the back of the leaf and the uneven distribution of droplets are the problems of traditional agricultural ground plant protection machinery, which leads to low agricultural control efficiency. Combined with the advantages of electrostatic spray technology and the characteristics of high working efficiency and low probability of droplets drift of ground sprayer, an inductive electrostatic boom spray system based on embedded electrode structure is designed and mounted on a large self-propelled boom sprayer for field testing. Based on the working characteristics of the fan nozzle and the analysis of the theory of charge, the inductive electrostatic spray device is designed. The performance of the device is tested and the rationality of the system design is verified by COMSOL numerical simulations, charge-to-mass ratio, and particle size distribution measurements. The spray deposition scanning software and the Box-Behnken experimental design method are used to analyze the spray droplet deposition rate and coverage density of the sprayer on the front and back of the target leaves. The results show that the embedded closed electrode structure designed in this paper can avoid the problem of electrode wetting, and the electric field generated by it is mainly concentrated in the spray liquid film area, and the intensity reaches 6~7 V/m. At the conventional application height (500 mm), the maximum charge-to-mass ratio is 2.91 mC/kg, and the average particle size is 168.22 μm, which is 12.87% lower than that of ordinary spray, when the spray pressure is 0.3 MPa and the electrostatic voltage is 12 kV. The results of field experiments show that the optimum combination of the working parameters with the spray speed is 8.40 m/s, the spray pressure is 0.35 MPa, the charging voltage is 11.50 kV, the amount of droplet deposition in the lower dorsal area of the blade is 1.44 µL·cm-2. This study can provide a certain basis for the application of electrostatic spray technology in ground sprayers.

Analysis of the Factors Affecting the Deposition Coverage of Air-Assisted Electrostatic Spray on Tomato Leaves

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.

Ultrathin-strut versus thin-strut stent healing and outcomes in preclinical and clinical subjects.

Compared with thin-strut durable-polymer drug-eluting stents (DP-DES), ultrathin-strut biodegradable-polymer sirolimus-eluting stents (BP-SES) improve stent-related clinical outcomes in patients undergoing percutaneous coronary intervention (PCI). Reduced stent strut thickness is hypothesised to underlie these benefits, but this conjecture remains unproven. We aimed to assess the impact of strut thickness on stent healing and clinical outcomes between ultrathin-strut and thin-strut BP-SES. First, we performed a preclinical study of 8 rabbits implanted with non-overlapping thin-strut (diameter/thickness 3.5 mm/80 μm) and ultrathin-strut (diameter/thickness 3.0 mm/60 μm) BP-SES in the infrarenal aorta. On day 7, the rabbits underwent intravascular near-infrared fluorescence optical coherence tomography (NIRF-OCT) molecular-structural imaging of fibrin deposition and stent tissue coverage, followed by histopathological analysis. Second, we conducted an individual data pooled analysis of patients enrolled in the BIOSCIENCE and BIOSTEMI randomised PCI trials treated with ultrathin-strut (n=282) or thin-strut (n=222) BP-SES. The primary endpoint was target lesion failure (TLF) at 1-year follow-up, with a landmark analysis at 30 days. NIRF-OCT image analyses revealed that ultrathin-strut and thin-strut BP-SES exhibited similar stent fibrin deposition (p=0.49) and percentage of uncovered stent struts (p=0.63). Histopathological assessments corroÂborated these findings. In 504 pooled randomised trial patients, TLF rates were similar for those treated with ultrathin-strut or thin-strut BP-SES at 30-day (2.5% vs 1.8%; p=0.62) and 1-year follow-up (4.3% vs 4.7%; p=0.88). Ultrathin-strut and thin-strut BP-SES demonstrate similar early arterial healing profiles and 30-day and 1-year clinical outcomes.

Achieving Complete Human Gingival Fibroblast Collagen Coverage on Implant Abutments through Vacuum Ultraviolet (VUV) Photofunctionalization.

The formation of a biological seal between implant abutments and the surrounding soft tissue is a preventive strategy against peri-implantitis. The aim of this study is to test the hypothesis that surfaces of prosthetic implant abutments treated with vacuum ultraviolet (VUV) light enhance the growth and function of human gingival fibroblasts. Implant abutments were treated with 172 nm VUV light for one minute. Untreated abutments were subjected as controls. Their surface properties were characterized using SEM, contact angle measurements, and chemical composition analysis. Human gingival fibroblasts were cultured on both untreated and VUV-treated abutments to evaluate cell attachment, proliferation, distribution, and collagen production. Cell detachment assays were also performed under various mechanical and chemical stimuli. After VUV treatment, implant abutments demonstrated a notable transition from hydrophobic to hydrophilic wettability. Surface element analysis revealed a considerable reduction in surface carbon and increases in oxygen and titanium elements on the VUV-treated surfaces. On day 1 of culture, 3.9 times more fibroblasts attached on VUV-treated abutments than on untreated control abutments. Fibroblastic proliferation increased 1.9-3.1 times on VUV-treated abutments, along with a significant improvement in the distribution of populating cells. Collagen production on VUV-treated abutments increased by 1.5-1.7 times. While untreated abutment surfaces showed voids and limited spread of collagen deposition, dense and full coverage of collagen was observed on VUV-treated abutments, with a great contrast in the challenging axial surface zone. Cell retention against mechanical and chemical detaching stimuli was increased 11.3 and 4.3 times, respectively, by VUV treatment. Treatment of implant abutments with VUV light for one minute resulted in a reduction of surface carbon and a transformation of the surface from hydrophobic to hydrophilic. This led to enhanced attachment, proliferation, and retention of human gingival fibroblasts, along with nearly complete collagen coverage on implant abutments. These in vitro results indicate the promising potential of utilizing VUV photofunctionalized implant abutments to enhance soft tissue reaction and sealing mechanisms.

Effect of operational parameters on droplet deposition characteristics using an unmanned aerial vehicle for banana canopy.

In recent years, as an important part of precision agricultural aviation, the plant protection unmanned aerial vehicle (UAV) has been widely studied and applied worldwide, especially in East Asia. Banana, as a typical large broad-leaved crop, has high requirements for pests and diseases control. The mechanization degree of plant protection management in banana orchard is low. Therefore, our study focuses on the effects of different flight heights (3-5m) and droplet sizes (50-150 μm) of plant protection UAV on the droplet deposition distribution characteristics of banana canopy. And the droplet deposition distribution in banana canopy and spraying drift of plant protection UAV and ground air-assisted sprayer were compared. The results showed that droplet size was the main factor affecting droplet deposition density, coverage, uniformity and penetration on both sides of banana canopy leaves. The droplet deposition density and coverage on the adaxial side of leaves were mostly significantly larger than that on the abaxial side. The flight height of 4m and the droplet size of 100 μm could make the adaxial side of banana canopy leaves have higher droplet deposition density (63.77 droplets per square cm) and coverage (12.75%), and can make the droplets effectively deposit on the abaxial side of banana canopy leaves, with droplet deposition density of 17.46 droplets per square cm and coverage of 1.24%. Choosing an appropriate flight height and a droplet size could improve the droplet deposition uniformity on both sides of banana canopy leaves, but the improvement was not significant. Moreover, at a same operational parameter combination, it was difficult to achieve the best droplet deposition density, coverage, uniformity and penetration at the same time. In addition, appropriately increasing the flight height and droplet size could help to improve the droplet deposition penetration on the adaxial side of banana canopy leaves, but there were few significant improvements. Compared with the plant protection UAV, the ground air-assisted sprayer had higher droplet deposition density and coverage on the abaxial side of banana canopy leaves, but had smaller droplet deposition coverage on the adaxial side. The droplet deposition density and coverage on the abaxial side of banana canopy leaves were obviously larger than the adaxial side during the spraying of ground air-assisted sprayer. The droplet drift distance of the ground air-assisted sprayer was farther than the plant protection UAV. The test results of this study can provide practical and data support for the UAV aerial application in banana orchard, and provide a valuable reference for the implementation of air-ground cooperation spraying strategy in banana orchard, which is of great significance to promote sustainable and intelligent phytoprotection of banana orchard.

Multifactorial analysis and experiments affecting the effect of fog droplet penetration in fruit tree canopies.

This study examines the impact of canopy density, side wind speed, nozzle tilt angle, and droplet size on droplet penetration during plant protection spraying operations. Experiments conducted in citrus orchards evaluated how side wind speed and nozzle tilt angle influence droplet penetration across various canopy densities. A Phase Doppler Analyzer (PDA) was used to assess droplet size variations under different nozzle tilt angles and side wind speeds, yielding a multiple linear regression equation (R2 = 0.866) that links nozzle tilt angle and side wind speed with droplet size. Results showed that droplet size decreases with increasing nozzle tilt angle at a constant crosswind speed. Further experiments investigated the effects of droplet size and canopy leaf area density on droplet penetration, involving three canopy leaf area densities, four wind speeds, and six nozzle tilt angles. Droplet deposition and canopy coverage were measured under various spraying parameters, with conventional operations (0° nozzle tilt and orthogonal wind speeds) serving as controls. The study found that adjusting nozzle tilt angle and wind speed enhances droplet penetration in different canopy structures. Optimal parameters varied with leaf area density (LAD): an 18° tilt angle and 3 m/s wind speed for a LAD of 5.94 m3/m3, a 45° tilt angle and 2 m/s wind speed for a LAD of 8.47 m2/m3, and a 36° tilt angle and 3 m/s wind speed for a LAD of 11.12 m2/m3. At 1 m/s, droplet deposition followed a downward parabolic trend with changes in nozzle tilt angle, whereas at 2 m/s, deposition followed an upward parabolic trend. At a side wind speed of 3 m/s, droplet deposition remained unchanged with nozzle tilt angle but decreased with increasing canopy density. Nonlinear regression analysis indicated that leaf area density had a greater impact on deposition differences than droplet size, with droplet penetration decreasing as leaf area density increased. This study provides a reference for enhancing fog droplet penetration techniques in plant protection operations, offering practical guidelines for optimizing spraying conditions and improving pesticide use efficiency in different canopy structures.

不同喷雾参数对流体动力式超声雾化喷嘴的沉积性能研究

In order to study the spraying effect of hydrodynamic ultrasonic atomizing nozzle under different spraying methods, and to investigate the practical application effect of hydrodynamic ultrasonic atomizing nozzle in agriculture, the atomization angle test and droplet size test under different spraying conditions were designed. Different spraying conditions atomization angle test and droplet size test were designed, the test results data were recorded, the pattern of change of the data was observed, and the data were fit to give the data changes in line with the functional equation; different spraying conditions and different corn leaf position droplet deposition coverage test were designed and the value of the deposition coverage of each position was recorded. The results showed that: the maximum value of the variation of atomization angle under different spraying conditions was 75.49°, and the minimum value was 14.49°; the maximum value of the variation of droplet size was 18.23 μm, and the minimum value was 4.78 μm; and the droplet deposition coverage was the highest in the mid-leaf position of the upper and lower leaves of the maize when the input air pressure was 0.3 MPa, which was 86.98% and 46.97%, respectively. Fitting the atomization angle data and droplet size data, the R2 of the binomial fit was 0.85 and 0.94, respectively, and the Adjusted R2 was 0.87 and 0.88, respectively, which made the fitting function meaningful and the fitting accuracy high. The hydrodynamic ultrasonic atomizing nozzle has a great advantage in generating small droplet sizes and performs well in deposition effect, and the experimental results can provide a reference for the research of hydrodynamic nozzles in the application technology.

PSXII-15 Automatic Estimation of Body Condition Score in Finished Cattle Using Deep Learning Computational Architectures in Two-Dimensional Images

Abstract The objective of this research was to investigate the possibility of using computational architectures of deep learning neural networks (deep learning) in two-dimensional images to automatically estimate the BCS (body condition score) in beef cattle. Data collection lasted from March 2021 to December 2022 and was carried out on a commercial farm in Mato Grosso do Sul, Brazil. Data from 1,570 animals of different genetic compositions, sex classes, ages and body weights were used. The animals were randomly selected in the confinement stalls, identified and concomitantly. To obtain the RGB digital images, the 3DBeef @Tech device was used, which was implemented in Python (based on OpenCV, 2015). The sensor was positioned in the passageway at a distance of 2.50 meters, allo wing the collection of images of only one animal at a time. The bBCS was evaluated remotely by trained professionals during the data collection period, ranging from 1 to 9, through the visualization of fat deposition and muscle coverage in certain anatomical points of the animal. The collected images and evaluations were used as input for a segmentation convolutional neural network (CNN; Figure 1). The labeled data set was divided into training, validation and testing, respectively in the proportions of 65%, 25% and 10%. A deep neural network was constructed to classify BCS using Python and the deep learning library Tensorflow and run through a Pro+ instance of Google Collaboratory. The results obtained show that, despite the small amount of data currently available for training, the neural network had a performance designed to classify BCS, with training accuracy of 80.5% and validation accuracy of 65.9% (Figure 2 and 3). when compared with professional raters. The validation still exhibited accuracy, recall, F1-score and AUC of 0.6676, 0.6562, 0.6562 and 0.9519 (P < 0.05), respectively. Despite the fact that the BCS assessment is a problem of difficult visual classification, both due to the variability of possible scenarios and the subtle difference between different BCS scores. It is believed that with a greater number of evaluated images, an accuracy greater than 90% will be achieved for the BCS. Therefore, it is necessary to continue with studies to obtain a greater number of images collected in search of greater accuracy.

Efficacy of Two Tank-Mix Adjuvants to Control Mango Thrips Using a UAV Sprayer

Thrips have become some of the most challenging pests to control in mango production due to their short developmental time, hidden locations and resistance to pesticides, in the tropical regions of China. To improve pesticides efficacy, the tank-mix adjuvants Qi Gong (QG) and the thrips attractant Lv Dian (LD) were added when using an unmanned aerial vehicle (UAV) to control thrips. The surface tension, contact angle on mango leaves, droplet size, spreading rate, and drying time of the two tank-mix adjuvants were determined. The effects of the two tank-mix adjuvants using a UAV sprayer on the droplet coverage and control efficacy against thrips on mango inflorescences were tested through field trials. The results showed that both QG and LD could reduce the surface tension of the liquid and the contact angle on mango leaves and could increase the spreading performance. The droplet coverage in the upper layer of the canopy was about 2% higher than that in the lower layer, and the coverage at the top of the panicle was 5% higher than that at the bottom. QG improved the deposition coverage of mango inflorescences by about 31.5%. The addition of QG increased the efficacy by 18.24% and 8.03%, respectively, at florescence and the young fruit stage. The addition of the LD increased the efficacy by 24.56% and 14.38%, respectively, at florescence and the young fruit stage. These test results can provide a scientific basis for the control of mango thrips with UAVs.

Evaluation of the droplet deposition and control effect of a special adjuvant for unmanned aerial vehicle (UAV) sprayers

Unmanned aerial vehicle (UAV) sprayers have been widely used in agriculture. With the goals of using pesticides efficiently and reducing their dosage, we evaluated the effects of adding and not adding special adjuvants to UAV sprayers on droplet deposition and the control effect of leaf folder insects. The deposition quantity and coverage area of UAV sprayers with the Kao Adjuvant A-200® on rice leaves were better than those without the Kao Adjuvant A-200®. Regarding the control effect on rice leaf rollers, UAV sprayers with the Kao Adjuvant A-200® were also better, and they also met the pesticide residue limit for brown rice. Kao Adjuvant A-200® can improve the UAV sprayer's droplet deposition and pest control effect. When the pesticide dosage was reduced by 30%, UAV sprayers with Kao Adjuvant A-200® can achieve a good control effect, which is very helpful in reducing the pesticide dosage.

Improving agricultural robot patch-spraying accuracy and precision through combined error adjustment

Site-specific weed management (SSWM) involves precision spraying operations based on the spatial variability of weeds in the field. High spraying precision enables extensive economic and environmental benefits. We developed a high-precision patch-spraying robot system based on weed maps to conduct patch-spraying operations at the individual plant scale. The patch-spraying droplet deposition effect is evaluated by post-spraying droplet deposition images. The agricultural robot mainly consists of a walking chassis, spraying, and control systems. The walking chassis provides walking power and support for the suspended spraying system. Combining the static structural and dynamic error models of the robot improves patch-spraying accuracy and precision. Twelve patch-spraying simulations were carried out on the leveling site. Different correction methods and driving speeds were tested, with driving rates of 0.5, 1.0, and 1.5 m/s. Aerial images of the patch-spraying process were evaluated using pixel point-based discriminant statistics after operation completion. The droplet deposition coverage accuracy ranged from 95.9 to 98.8 %. The center of droplet deposition offset distance was 3.7–7.2 cm. Field results showed that the patch-spraying weed control rate based on individual plant scales (spraying precision ≤ 15 cm) was 94.2–98.1 %. In summary, the developed agricultural robot performs patch-spraying operations at the individual plant scale. Patch-spraying accuracy and precision are improved by modeling corrections for random errors. A general error correction method for the deposition position of fog droplets is explored to achieve precise droplet delivery in the walking state of plant protection operation equipment.

Growth morphology and magnetic properties of Gd adatoms on h-BN template: From single atom to small cluster and monolayer

Atomic assembly of surface-supported nanostructures with high structural stability, large magnetic moment and magnetic anisotropy energy (MAE) hold great potential applications in spintronic and magnetic storage devices. With the changes of deposition coverage of Gd adatoms on the hexagonal boron nitride (h-BN) template, we systemically investigate the low-lying structures and magnetic properties of Gdn (n=1–19) clusters and monolayers (1ML-Gd and 2ML-Gd) by combining various theoretical methods including the spin–orbital coupling (SOC) density functional theory (DFT), abinitio molecular dynamics (AIMD) simulations and lattice dynamical calculations. Favorable adsorption sites and preferable orientations as well as distinguishing electronic structures have been thoroughly explored to reveal the bonding characteristics and growth models of Gd clusters and thin films. We demonstrate that the planar Gd clusters/monolayers deposited on h-BN surface can exhibit the energetically, dynamically, thermally, and thermomagnetically stable at high temperature of 500 K. The Gd-B covalent and ionic bonding interactions instead of Gd-N interactions give the synergetically contributions for stabilizing small clusters on planar h-BN sheet via the hybridizations of Gd-5d and B-2pz orbitals, while Gd-N covalent bonds participate in additionally bonding interaction for the depositions of large clusters on corrugated h-BN sheet due to the transformations from B/N-sp2 to B/N-sp3 hybridizations. Robust ferromagnetic (FM) couplings with large spin magnetic moments about 7.6 μB per Gd atoms are always found to be the ground states. Orbital magnetic moments of −0.10∼−0.37 μB per atom and large MAEs in few meV are primarily contributed by Gd-5d electrons. We propose that the Ruderman–Kittel–Kasuya–Yosida (RKKY) interaction mediated by 5d electrons determines the long-term FM coupling between Gd atoms, and we estimate the Curie temperatures ranging from 150 K to 60 K for different Gd deposited systems. The excellent structural and magnetic stability as well as large magnetic moment and MAEs therefore facilitate Gd cluster and thin film the promising candidates for spintronic applications.

Low-volume precision spray for plant pest control using profile variable rate spraying and ultrasonic detection.

Spraying chemical pesticides is one of the important means to control plant pest, and the profile variable spraying is an important technology to achieve precise pesticide application. A profiling tracking control method and an improved algorithm based on CMAC-PID (Cerebellar Model Articulation Controller- Potential Induced Degradation) were proposed in the paper. The test results of the sprayer profiling tracking of the tree canopies showed that the profiling control system using the improved algorithm had significantly better dynamic tracking performance, and the overall mean tracking error was reduced by 35.0%, compared with the traditional CMAC-PID. A spray flow calculation method based on tree canopy volume and leaf area density was proposed. Outdoor testing of the profile variable spraying and conventional spraying was carried out. There was no significant difference between the two spraying methods in terms of droplet coverage, VMD (Volume Median Diameter), NMD (Number Median Diameter), spray quality parameter and relative span coefficient, as well as droplet deposition density. The spray coefficient of variation was reduced by 25.9% and 21.9% inside and outside the tree canopy, respectively. The mean value of the ground deposition coverage of the profile variable spraying and the traditional spray was 13.0% and 33.2%, respectively, indicating a significant impact on the ground droplet deposition coverage by the two spraying methods. The spray flow rate of the profile variable spraying could be decreased by 32.1% compared to the conventional spraying. Profile variable spraying would reduce the cost associated with pesticide use and environmental pollution.

Predicting the Stability and Loading for Electrochemical Preparation of Single-Atom Catalysts

Underpotential electrochemical deposition is a convenient approach for precisely controlling the fabrication process of single-atom catalysts (SACs). In achieving a balance between raising the loading of SACs and suppressing the aggregation of the adsorbates, the working electrode potential should be deliberately optimized, for which the adsorption isotherm of the loading of atomically dispersed adsorbates versus electric potential is of crucial importance in performance tuning. We report an integrated theoretical scheme for simulating the adsorption isotherm, which can enormously accelerate the evaluation of the adsorption energy for large model systems by combining our recently proposed constant-potential calculation scheme with the cluster expansion (CE) model, as well as accurately estimate the configurational effect through a thermodynamic integration (TI) computation based on Monte Carlo (MC) simulations. With the established simulation scheme, the surface map of the adsorption free energy as a function of deposition coverage and electric potential is computed for atomically dispersed copper on 1T′-MoS2, which is further employed to reasonably estimate the equilibrium coverage of the deposit at varying electric potentials and predict the feature of the adsorbate distribution pattern, as well as simulate the cyclic voltammogram (CV). Besides, based on the study of nine metal/transition-metal dichalcogenide (TMD) systems, we demonstrate that the well-characterized potential-related metal–substrate and metal–metal interactions provide rational criteria for evaluating the stability of SACs against aggregation under electrochemical conditions.