Conventional Spray Research Articles

High temperature total consumption sample introduction system coupled to microwave plasma optical emission spectrometry (MIP-OES) for the analysis of aqueous samples

The high temperature torch integrated sample introduction system (hTISIS) is coupled to microwave plasma optical emission spectrometry (MIP-OES) for the first time. The goal of this work is to develop an accurate analysis of digested samples under continuous sample aspiration mode by coupling the hTISIS to a MIP-OES instrument. To achieve this, different operating conditions such as, nebulization flow rate, liquid flow rate and the spray chamber temperature were optimized in terms of sensitivity, limits of quantification (LOQs) and background equivalent concentration (BECs) for the determination of Ca, Cr, Cu Fe, K, Mg, Mn, Na, Pb and Zn, and these values were compared with those reported with a conventional sample introduction system. Under optimum conditions (0.8–1 L min−1, 100 μL min−1 and 400 ᵒC, respectively), the hTISIS improved MIP-OES analytical figures of merit and shortened 4-times wash out times with respect to a conventional cyclonic spray chamber, reporting an enhancement factor in the sensitivity among 2–47 times and LOQs from 0.9 to 360 μg kg−1. Once the best operating conditions were set, the magnitude of the interference caused by 15 different acid matrices (2, 5 and 10% w/w of HNO3, H2SO4, HCl and mixtures of HNO3 with H2SO4 and HNO3 with HCl) was significantly lower for the former device. Finally, 6 different digested oily samples (used cooking oil, animal fat, corn oil and the same samples after a filtration step) were analyzed by means of an external calibration approach based on the use of multielemental standards prepared in 3% (w/w) HCl solution. The obtained results were compared against those supplied by a conventional methodology employing an inductively coupled plasma optical emission spectrometry, ICP-OES, instrument. It was clearly concluded that the hTISIS coupled to MIP-OES afforded similar concentrations as compared to the conventional methodology.

Enhancement of the vertical thermal conductivity in conductive silicone composites using hybrid fillers and double-sided coating process

Herein, we propose an effective method for improving the vertical thermal conductivity of conductive silicone composites using thermally conductive hybrid fillers and a double-sided coating process. By applying the resin mixing and screen-printing method instead of the conventional spray coating, it was possible to prevent the shrinkage of the conductive composite fabric. It was found that a higher graphene content in the hybrid filler resulted in a higher thermal conductivity for the conductive composites. Moreover, a double-sided coating of conductive silicone additionally improved the vertical thermal conductivity of the fabric due to the formation of a double-sided heat transfer network.

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.

The Efficacy of Cold Atmospheric Plasma Deposited Antibiotics on Titanium Surfaces and Their Elution Liquids Against Staphylococcus aureus Growth Over Time

Cold atmospheric plasma (CAP) was used to deposit antibiotics, penicillin, and ciprofloxacin, separately onto titanium coupons. The antibiotic coating parameters were varied using a design of experiment software which factored in plasma power, bacterial and antibiotic load. The antimicrobial activity of the plasma deposited antibiotics was benchmarked against conventional spray coated materials and the effect of the plasma exposure is discussed. The deposited antibiotics were characterized using various surface analysis and microbiological techniques. It was found that the antibiotics were not degraded and retained antibiotic activity against planktonic <i>Staphylococcus aureus</i> bacteria. However, the presence of the plasma during coating did alter the elution profile of the antibiotics and helped prolong the activity of the antibiotics on the metal surface. This study may contribute to the development of novel implant coating procedures that can offer prolonged antimicrobial protection.

Effects of spray adjuvants and operation modes on droplet deposition and elm aphid control using an unmanned aerial vehicle

A conventional spraying mode and a fully autonomous fruit tree operation mode using a model DJ T30 unmanned aerial vehicle (UAV) were used to control aphids control on elm trees and to clarify the distribution of droplets in elm trees sprayed by an UAV. The effects of six aviation spray adjuvants on elm canopy droplet deposition and aphid control were evaluated. ImageJ software was used to analyze and measure the droplet density and deposition of water sensitive paper in two modes; this was done to calculate the droplet uniformity, depositional penetration and droplet penetration, and to verify the aphid control effect. The results showed that the droplet density increased by 79.7%-100.7% in the upper canopy and 0-394.1% in the lower canopy without adjuvants in the fully autonomous fruit tree operation mode. The upper canopy deposits increased by 65.7%-179.3%, and the lower canopy increased by 0-152.8%. When adjuvants were added, the droplet density in the upper canopy increased by 49.7-56.1% using Jiexiaofeng (JXF), and the lower canopy increased by 138.2%-177.8% using JXF, 45.8%-141.3% using Beidatong (BDT), 45.5%-92.9% using Gongbei (GB), 0-93.5% using Maisi (MS), and 0-95.2% using Manniu (MN). The deposits of the upper canopy increased by 888.1-1154.2% using JXF, 0-1298.3% using MN, 0-343.9% using BDT, 0-422.5% using GB, 0-580.3% using MS. The lower canopy increased by 746.4%-1426.0% using JXF, 226.2%-231.0% using BDT, 435.8%-644.0% using GB, 255.0%-322.4% using MS, and 249.3%-360.0% using MN. When JXF was added, the droplet uniformity, droplet penetration and depositional penetration were better than when using other adjuvants. The effects of JXF, BDT and GB in controlling aphids was significantly better than other adjuvants (p<0.05). The following control effects were observed; 94.1% with JXF, 93.1% with BDT, and 93.3% with GB after 3 d of application, and 97.9% with JXF, 95.6% with BDT, and 97.1% with GB after 7 d of application. At the same time, the application of the fully autonomous fruit tree operation mode and JXF can effectively improve the density and deposits, which will produce a superposition optimization effect. Our study focuses on the prevention and control of elm aphid infestations based on the operation mode of a UAV and aviation spray adjuvants, which can provide a baseline for the control of diseases and insect pests using UAVs in agriculture and forestry. Keywords: adjuvants, UAV, operation mode, droplet deposition, aphid DOI: 10.25165/j.ijabe.20231602.7424 Citation: Dou Z C, Fang Z H, Han X Q, Zeeshan M, Liu Y P, Lan Y B. Effects of spray adjuvants and operation modes on droplet deposition and elm aphid control using an unmanned aerial vehicle. Int J Agric & Biol Eng, 2023; 16(2): -.

Thermal Barrier Coatings: An Insight into Conventional Plasma Spray and Water-Stabilized Plasma Spray

Thermal barrier coating (TBC) systems have presented an ongoing design issue in bids to improve the lifespan of coatings. A TBC can support an extended lifespan by repairing cracks between interfacial layers during high thermal exposure while at the same time increasing coating thickness. Two deposition techniques, atmospheric plasma spray and water-stabilized plasma spray (WSP), have been distinguished to understand mechanical and thermal performance based on their contrasting torch systems and microstructural characterization. This insight paper will underline the superiority of WSP coating and the need to leverage existing technology by optimizing better deposition parameters for future fatigue-resistant TBC production.

Hybridized-flow flame spray (HFFS) process for the development of superior ceramic coatings

The present study deals with a novel, effective and single step thermal spray coating process development. The process is named as ‘Hybridized-Flow Flame Spray (HFFS) process’. The process is very much suitable for the development of ceramic coatings with superior properties when compared to conventional Powder Flame Spray (PFS) coatings. The HFFS process is capable in addressing the shortcomings (porosity, density, hardness, surface quality) of PFS coatings. The physical, mechanical and metallurgical analysis of PFS and HFFS coatings are done using density measurement kit, 3-D optical profilometer, Vickers and scratch hardness, and scanning electron microscope (SEM). The results show significant improvement in the properties. The increment in density (≈24%), hardness (Vickers ≈ 37% and scratch ≈ 126%); and decrement in coating thickness (≈35%) and average surface roughness (≈47%) of HFFS sprayed coatings are observed. The results are benchmarked with those of PFS coatings. The improved responses are attributed to the densification of coating structure and improved microstructural changes due to the presence of hybridized flow in the HFFS.

Wetting and deposition behaviors of pesticide droplets with different dilution ratios on wheat leaves infected by pathogens

The pesticide formulations should be diluted to different concentrations according to selected application methods. The structure and properties of crop leaf surfaces can undergo severe changes after infestation with pests or diseases. Previous studies have mostly focused on the interfacial behaviors of pesticide droplets on healthy plant leaves. Here, we prepared 25 % pyraclostrobin microemulsion and diluted it according to different dilution ratios corresponding to low volume and conventional volume spray methods. The dynamic wetting and deposition behaviors of pesticide solution on wheat leaves infected with powdery mildew were investigated. The surface structure and properties of wheat leaves covered by the fungus Blumeria graminis will be changed. Conidia produce more non-polar components. The droplets with low dilution were more likely to deposit and reach the Wenzel state on wheat powdery mildew leaves. However, the droplets with high dilution were difficult to wet and easy to break and rebound from leaf surfaces. This research guides the control of wheat powdery mildew with pesticides under different application methods and the interface interaction between pesticide droplets and hydrophobic leaf surfaces infected by pathogens.

Excellent thermal shock resistance of NiCrAlY coatings on copper substrate via laser cladding

• NiCrAlY layers were prepared on copper substrate via laser cladding technology. • Metallurgical bonding and excellent thermal shock resistance are obtained. • Lifetime of this NiCrAlY layers is much longer than NiCrAlY by other methods. Coatings are widely used to protect substrates in extreme thermal environments (e.g., arc heaters), and thermal shock resistance is a crucial parameter for the coatings, which requires tight interlayer bonding between coatings and substrates. In this work, NiCrAlY coatings were highly required for the pure copper substrate to restrict the electric arc in arc heaters. To overcome the bonding difficulty of coating on the copper surface, the NiCrAlY coatings were prepared by two laser cladding methods: conventional laser cladding (CLC) and high-speed laser cladding (HSLC). The microstructure, composition, and thermal shock resistance of NiCrAlY cladding layers prepared by both methods were investigated. Benefitting from the high cooling rate and high energy density, the HSLC-layer has better composition uniformity and tighter interlayer bonding than the CLC-layer, achieving a 30%–45% improvement in thermal cycling lifetime. Besides, the NiCrAlY layers prepared on copper substrate by both laser cladding methods exhibit 3–10 times better thermal shock resistance than those NiCrAlY layers prepared by conventional spraying methods. It further confirms the great effects of metallurgical bonding and composition uniformity on the thermal shock resistance of coatings. The NiCrAlY layers fail in the form of internal cracking and interface peeling, and the corresponding failure mechanism is discussed.

Spaetzle responds to the process of Neoseiulus barkeri resistance to Beauveria bassiana infection

The application of Beauveria bassiana is proved to be a feasible biological control measure against pest insects and mites (e.g. Liu et al. 2018; Al Khoury et al. 2020). But the complex and variable ecological environment can affect the efficiency of B. bassiana. Due to the powerful search and spread ability of predatory mites, they were proposed to carry and spread pathogenic microbial spores to places that are difficult to be covered by conventional spray methods (Chen et al. 2020; Hao et al. 2021). This biocontrol strategy of combining fungi with predator mites is predicted to play a synergistic role in pest control. Therefore, the tolerance of predator mites to B. bassiana and the underlying mechanism have been the subject of extensive research and remained to be explored further. The infection of insects by B. bassiana can induce insect innate immune response. Spaetzle protein (Spz), as an important ligand of insect Toll pathway, has been demonstrated to play an important role in insect innate immune defense system. &#x0D;

Nozzle Geometry and Particle Size Influence on the Behavior of Low Pressure Cold Sprayed Hydroxyapatite Particles

Low-pressure cold spray (LPCS) technology has attracted interest for the deposition of ceramic coatings due to the thermo-kinetic conditions experienced by the sprayed particles. Unlike conventional thermal spray techniques, the spraying conditions in LPCS can be controlled to avoid the formation of undesired phases. However, ceramics deposition through this process is still challenging. The present study includes a finite element analysis and simulation study of the kinetic conditions of ceramic particles in the LPCS process based on experimental data. The analysis seeks to discuss the effect of nozzle geometry on the kinetic and thermal energy of the sprayed particles at impact and elucidate how the particle travels within the high-velocity jet to be deposited onto a metallic surface. This work examines the behavior of hydroxyapatite particles as a function of particle size and nozzle geometry during LPCS deposition. Interestingly, the results from this research suggest that particle size and nozzle geometry have an influence on the deposition of hydroxyapatite particles. Inertia of large particles proved to be beneficial in keeping their trajectories, allowing them to contribute to the formation of the coatings. Nozzle geometry modifications produced changes in the jet profile and affected the homogeneity of the coatings obtained. This finding contributes to a better understanding of the deposition of hydroxyapatite particles by cold spraying.

Photocurable Coatings to Improve the Mechanical Properties of 3D Printable Expanding Foams.

Recent developments of highly expandable foaming pre-polymer resins for lithographic additive manufacturing have allowed for the creation of structures larger than a printer's build envelope. To fully utilize the capabilities of this technology, the mechanical properties of these foams must be improved. This manuscript presents one method for strengthening these lightweight polymeric structures via aerosol spray application of a high-strength, low-viscosity photocurable coating. This method is free from the reliance on often complex, large, or bulky on-site equipment ordinarily required by conventional high-strength spray coating. The newly formulated photocurable resin can be applied using an ordinary cordless paint sprayer and cured using sunlight in less than a minute, enabling the rapid production of large, load-bearing structures from a small volume of feedstock and low-cost portable equipment. A comprehensive screening process for resin formulations, detailed mechanical compression and tensile analysis of coated polymer structures, and an applied technical demonstration of the technology are described. The photocurable coating described herein greatly strengthens porous polymeric structures using a method that can be easily implemented.

Development and evaluation of fungicide-amended urea briquettes (FAUB's) to combat fruit rot disease of arecanut: A farmers-friendly approach

Fruit rot disease (FRD) of arecanut caused by Phytophthora meadii (McRae) is a major limiting factor in arecanut production across the globe. Prophylactic sprayings of Bordeaux mixture (1%) and other oomycete-specific fungicides are recommended to manage this serious malady in arecanut. However, the tall nature of palms is a greater challenge for the application of plant protection measures on fruit bunches. Manual climbing of the palms during the rainy season is yet another risky task for proper spraying of chemicals up to the crown region. In this context, fungicide-loaded urea briquettes (FAUB's) were developed and assessed under field conditions against FRD in arecanut. Results proved that systemic fungicide-based urea briquettes are highly potent in protecting arecanut from FRD infection. Meanwhile, in the modern fungicidal delivery approach, the ambient fungicides such as fosetyl-Al, a combination of fosetyl-Al - propineb briquettes had achieved stronger fungicidal activity against FRD, reducing severity by 70% when applied twice with increased dry nut yield of 100% compared to control plots. Fosetyl-al briquettes found significantly higher in terms of control efficiency (Severity of 8.5 ± 0.22, 80%), yield response (19.04 ± 0.39q/ha), and economic analysis (3,08,400 Rs./ha). Further, the present study demonstrated that the soil application of FAUB's is an alternative to arduous conventional spraying. The experiment proved and demonstrated that, FAUB's could potential replacement for Bordeaux mixture and copper-oxychloride application under field conditions. Hence, we recommend to implement in integrated FRD management program.

Porous Covalent Organic Polymer Coordinated Single Co Site Nanofibers for Efficient Oxygen-Reduction Cathodes in Polymer Electrolyte Fuel Cells.

Nitrogen-coordinated single-cobalt-atom electrocatalysts, particularly ones derived from high-temperature pyrolysis of cobalt-based zeolitic imidazolate frameworks (ZIFs), have emerged as a new frontier in the design of oxygen reduction cathodes in polymer electrolyte fuel cells (PEFCs) due to their enhanced durability and smaller Fenton effects related to the degradation of membranes and ionomers compared with emphasized iron-based electrocatalysts. However, pyrolysis techniques lead to obscure active-site configurations, undesirably defined porosity and morphology, and fewer exposed active sites. Herein, a highly stable cross-linked nanofiber electrode is directly prepared by electrospinning using a liquid processability cobalt-based covalent organic polymer (Co-COP) obtained via pyrolysis-free strategy. The resultant fibers can be facilely organized into a free-standing large-area film with a uniform hierarchical porous texture and a full dispersion of atomic Co active sites on the catalyst surface. Focused ion beam-field emission scanning electron microscopy and computational fluid dynamics experiments confirm that the relative diffusion coefficient is enhanced by 3.5 times, which can provide an efficient route both for reactants to enter the active sites, and drain away the produced water efficiently. Resultingly, the peak power density of the integrated Co-COP nanofiber electrode is remarkably enhanced by 1.72 times along with significantly higher durability compared with conventional spraying methods. Notably, this nanofabrication technique also maintains excellent scalability and uniformity.

Real-Time Detection of Seedling Maize Weeds in Sustainable Agriculture

In recent years, automatic weed control has emerged as a promising alternative for reducing the amount of herbicide applied to the field, instead of conventional spraying. This method is beneficial to reduce environmental pollution and to achieve sustainable agricultural development. Achieving a rapid and accurate detection of weeds in maize seedling stage in natural environments is the key to ensuring maize yield and the development of automatic weeding machines. Based on the lightweight YOLO v4-tiny model, a maize weed detection model which combined an attention mechanism and a spatial pyramid pooling structure was proposed. To verify the effectiveness of the proposed method, five different deep-learning algorithms, including the Faster R-CNN, the SSD 300, the YOLO v3, the YOLO v3-tiny, and the YOLO v4-tiny, were compared to the proposed method. The comparative results showed that the mAP (Mean Average Precision) of maize seedlings and its associated weed detection using the proposed method was 86.69%; the detection speed was 57.33 f/s; and the model size was 34.08 MB. Furthermore, the detection performance of weeds under different weather conditions was discussed. The results indicated that the proposed method had strong robustness to the changes in weather, and it was feasible to apply the proposed method for the real-time and accurate detection of weeds.

Application of Thermal Spray Coatings in Electrolysers for Hydrogen Production: Advances, Challenges, and Opportunities

AbstractThermal spray coatings have the advantage of providing thick and functional coatings from a range of engineering materials. The associated coating processes provide good control of coating thickness, morphology, microstructure, pore size and porosity, and residual strain in the coatings through selection of suitable process parameters for any coating material of interest. This review consolidates scarce literature on thermally sprayed components which are critical and vital constituents (e. g., catalysts (anode/cathode), solid electrolyte, and transport layer, including corrosion‐prone parts such as bipolar plates) of the water splitting electrolysis process for hydrogen production. The research shows that there is a gap in thermally sprayed feedstock material selection strategy as well as in addressing modelling needs that can be crucial to advancing applications exploiting their catalytic and corrosion‐resistant properties to split water for hydrogen production. Due to readily scalable production enabled by thermal spray techniques, this manufacturing route bears potential to dominate the sustainable electrolyser technologies in the future. While the well‐established thermal spray coating variants may have certain limitations in the manner they are currently practiced, deployment of both conventional and novel thermal spray approaches (suspension, solution, hybrid) is clearly promising for targeted development of electrolysers.

Scalability of Protonic Ceramic Electrochemical Cell for Industrial Applications at Idaho National Laboratory

Novel protonic ceramic electrochemical cells (PCECs) are manufactured and tested at Idaho National Labs with the intention of scaling these materials for industrial application and market penetration. The focus of the presented work is to develop methodologies that can be used to translate the novel research executed at INL to industrial manufacturing and testing. The appeal to invest effort toward PCEC technology stems from a favorable efficiency, high proton conductivity, and low activation energy at operating temperatures between 400-600°C leading to greater performance and better durability than oxygen conducting solid ceramic electrochemical cells with the promise to reduce the cost. The challenge with PCEC arises from obstacles in the materials that project concerns of unreliability. Presently these concerns are being addressed at INL by implementing robust quality management (QA/QC) methodologies to ensure repeatable and reproducible fabrication, data, and results. From raw power supply to utilize conventional ceramic manufacturing and power spray coating to the design of PCEC, we successfully transitioned from 10 mm and 1” button to planer 5x5cm, and 10x10cm cells. The PCEC have been long term tested for 1000 hours under electrolysis conditions at 600°C resulting in a current density of -0.7 A/cm2 operated at 1.3V. The outcomes of these efforts effectively demonstrate that manufactured PCEC technology can successfully contribute to the increasingly diversifying energy portfolio of global economies that are beginning to invest in green hydrogen production as well as flexible chemical manufacturing pathways (e.g. CO2 conversion and ammonia synthesis).

Evaluation on the microstructure and thermal infrared emissivity of Ca2+-doped ytterbium chromate coating deposited by saucer-shaped porous feedstocks for high-temperature thermal protection

A high infrared emissivity coating with porosity of 16.2 % was deposited on Ni-based alloy by saucer-shaped porous feedstocks using the atmospheric plasma spraying technique. The solid-phase reaction method was employed to synthesize Ca2+-doped YbCrO3 ceramic powders, and then the saucer-shaped porous feedstocks were obtained by electrostatic spraying accompanied by heat treatment, and the conventional spray drying feedstocks were used as comparison. Compared with the conventional structural coating, the coating achieved by saucer-shaped feedstocks shows higher porosity and surface roughness due to the insufficient melting of the feedstocks with larger diameters in the plasma flame. Therefore, the coating achieved by saucer-shaped feedstocks exhibits a bimodal organization similar to that of nanostructured thermal barrier coatings. Compared with the conventional coating, the coating with new structure shows a higher emissivity value of 0.9460 at 1–14 µm waveband at room temperature due to the higher surface roughness (7.12 μm). Moreover, the average emissivity of coatings with roughness ranging from 0.93 µm to 7.12 µm is all above 0.91. More importantly, although the infrared emissivity of all coatings with different roughness decreases with the increase of temperature, they still remain above 0.77 at 1–14 µm when the temperature reaches 1200 °C.

Young’s Modulus and Residual Stresses of Oxide-Free Wire Arc Sprayed Copper Coatings

Conventional thermal spraying processes are almost exclusively carried out in an air atmosphere, resulting in the oxidation of the particle surfaces and interfaces within the coating and between the substrate and coating. Furthermore, the initial process of surface activation conventionally takes place in an air atmosphere, preventing an oxide-free interfacial transition. Consequently, the application of spraying materials with high oxygen affinity represents a major challenge. To overcome these issues, the present study utilized silane-doped inert gases to create an environment in which the oxygen concentration was equivalent to the residual oxygen content in an extreme high vacuum. By transferring the corundum blasting and coating process (wire arc spraying) to this environment, materials with a high oxygen affinity can be applied without oxidation occurring. For industrial use, this is an interesting prospect, e.g., for repair coatings, as the homogeneity of the composite is improved by a non-oxidized coating. Using the example of arc-sprayed copper coatings, the microstructure and mechanical properties of the coatings were analysed. The results showed that the oxide-free, wire arc sprayed copper coatings exhibited an improved wetting behaviour resulting in a significant reduction of the coating porosity. Moreover, the improved wetting behaviour and led to an increase in the bonding rate and apparent Young’s modulus. Contrary to expectations, the residual stresses decrease although relaxation mechanisms should be inhibited, and possible reasons for this are discussed in the paper.

LettuceTrack: Detection and tracking of lettuce for robotic precision spray in agriculture.

The precision spray of liquid fertilizer and pesticide to plants is an important task for agricultural robots in precision agriculture. By reducing the amount of chemicals being sprayed, it brings in a more economic and eco-friendly solution compared to conventional non-discriminated spray. The prerequisite of precision spray is to detect and track each plant. Conventional detection or segmentation methods detect all plants in the image captured under the robotic platform, without knowing the ID of the plant. To spray pesticides to each plant exactly once, tracking of every plant is needed in addition to detection. In this paper, we present LettuceTrack, a novel Multiple Object Tracking (MOT) method to simultaneously detect and track lettuces. When the ID of each plant is obtained from the tracking method, the robot knows whether a plant has been sprayed before therefore it will only spray the plant that has not been sprayed. The proposed method adopts YOLO-V5 for detection of the lettuces, and a novel plant feature extraction and data association algorithms are introduced to effectively track all plants. The proposed method can recover the ID of a plant even if the plant moves out of the field of view of camera before, for which existing Multiple Object Tracking (MOT) methods usually fail and assign a new plant ID. Experiments are conducted to show the effectiveness of the proposed method, and a comparison with four state-of-the-art Multiple Object Tracking (MOT) methods is shown to prove the superior performance of the proposed method in the lettuce tracking application and its limitations. Though the proposed method is tested with lettuce, it can be potentially applied to other vegetables such as broccoli or sugar beat.