Design of precision variable-rate spray system for unmanned aerial vehicle using automatic control method

In order to reduce the use of chemical pesticides in crop plant protection and improve the utilization efficiency of pesticides,it is necessary to study advanced application machinery and application techniques.The use of unmanned aerial vehicle(UAV)for pesticide spraying has the characteristics of less application,strong penetrability,wide applicability and flexible operation scheduling,and has gradually become one of the important development directions in the field of aviation plant protection.However,the operation process of the UAV is often affected by meteorological factors and human manipulation,resulting in poor actual operation with inaccurate spray volume and uneven application.Therefore,to improve the stability and uniformity of the application of the plant protection UAV under variable operating conditions,in this paper a real-time control method was proposed for the application flow rate,and a precision variable-rate spray system was designed based on single-chip microcomputer and micro diaphragm pump that can controls the flow rate of the pump in real time with the changes of the operating state.The response s-peed of the variable-rate spray system was tested.The average control response time of the system was 0.18 s,and the average stability time of the pump flow change was 0.75 s.The test results showed that the system has a quick response to the working state and the adjustment of the target flow of the pump can be quickly completed to realize the variable-rate spray function.The research results can provide a reference for the practical application of plant protection UAV variable-rate spray system.

Spatial distribution visualization of PWM continuous variable-rate spray

Pesticide application is a dynamic spatial distribution process,in which spray liquid should be able to cover the targets with desired thickness and uniformity.Therefore,it is important to study the 2-D and 3-D(dimensional)spray distribution to evaluate spraying quality.The curve-surface generation methods in Excel were used to establish 1-D,2-D,and 3-D graphics of variable-rate spray distribution in order to characterize the space distribution of the variable-rate spray.The 1-D,2-D,and 3-D distribution graphs of Pulse-Width Modulation(PWM)-based continuous variable-rate spray were developed to provide a tool to analyze the distribution characteristics of the spray.The 1-D graph showed that the spray distribution concentrated toward the center of the spray field with the decreased flow-rate.The 2-D graph showed that the spray distribution always spread as the shape of Normal Probability Distribution with the change of the flow-rate.The 3-D graph showed that the spray distribution tended to be uniform when the sprayer travelled forward at the appropriate speed.This study indicated that the visualization method could be directly used for analysis and comparison of different variable-rate spray distributions from different experimental conditions and measuring methods.

Revising Nitrogen Recommendations for Wheat in Response to the Need for Support of Variable-Rate Nitrogen Application

Sampling studies in North Dakota conducted from 1994 to 2003 showed that variable-rate N application could be practically directed with zone soil sampling. Results from variable-rate N studies using zone soil sampling were often less than rewarding due in part to the use of a whole-field predicted yield-based formula for developing the N recommendation in each zone. Nitrogen rate studies on spring wheat and durum were established in 2005 through 2009 with the objective to reexamine N recommendations and construct a new system if necessary. The results of the study and archived wheat N response data showed that the state should be divided into three separate N response regions. Within each region historic yields from low to high productivity were defined. The gross N rate was determined using the return-to-N concept developed in the US corn-belt states but with additional consideration for wheat protein value The gross N rate is then modified by credits for previous crop, soil test N from zone soil sampling, tillage systems, excessive straw from the previous year, relative susceptibility to nitrate leaching or denitrification. Finally, the user is encouraged to use common sense and consider whether particular fields have characteristics that require more or less N fertilizer than suggested by the recommendation formulas.

New algorithm for variable-rate linear broadcast network coding

To adjust the variance of source rate in linear broadcast networks, global encoding kernels should have corresponding dimensions to instruct the decoding process. The algorithm of constructing such global encoding kernels is to adjust heterogeneous network to possible link failures. Linear algebra, graph theory and group theory are applied to construct one series of global encoding kernels which are applicable to all source rates. The effectiveness and existence of such global encoding kernels are proved. Based on 2 information flow, the algorithm of construction is explicitly given within polynomial time O（｜E｜ ｜T｜.ω^2max）, and the memory complexity of algorithm is O（｜E｜）. Both time and memory complexity of this algorithm proposed can be O（ωmax） less than those of algorithms in related works.

A unified result for variable-rate linear network coding

Fong et al.analyzed variable-rate linear network coding for linear broadcast.However,the authors didn't investigate it for the other three types of linear network codes.In this paper,by simple and clear proofs,it is found that there are similar results for variable-rate linear generic and linear dispersion if the field size is large enough.It means that linear generics and linear dispersions of different dimensions can be implemented on the same network,while each non-source node is required to store only one copy of the local encoding kernel within a session.Moreover,an example is given to show that there isn't a similar result for linear multicast.

Design and Experiment of Slave Computer Control System for Applying Variable-rate Liquid Fertilizer

In order to increase the applying rate of liquid fertilizer and reduce environmental pollution, a slave computer control system for applying variable-rate liquid fertilizer was designed. The system used SMC as core processor and electrically controlled pressure regulator as execution component. The characteristic equation of the system was obtained by using classical control theory. Results indicated that the characteristic equation met the requirements of routh-criterion, which indicated the working process of the system was stable. Performance of the slave computer was verified via bench tests. Results demonstrated that there was no significant influence on the response from interclass error. The fertilization error was less than 0.9, and the fertilization accuracy was larger than 97%. The liquid fertilizer emitted by the fertilizing devices had no significant difference in uniformity, which met the demands of the slave computer control system for applying variable-rate liquid fertilizer.

Spray pyrolysis feasibility of tungsten substitution for cobalt in nickel-rich cathode materials

Cobalt(Co)serves as a stabilizer in the lattice structure of high-capacity nickel(Ni)-rich cathode materials.However,its high cost and toxicity still limit its development.In general,it is possible to perform transition metal substitution to reduce the Co content.However,the traditional coprecipitation method cannot satisfy the requirements of multielement coprecipitation and uniform distribution of elements due to the differences between element concentration and deposition rate.In this work,spray pyrolysis was used to prepare LiNi_(0.9)Co_(0.1-x)W_(x)O_(2)(LNCW).In this regard,the pyrolysis behavior of ammonium metatungstate was analyzed,together with the substitu-tion of W for Co.With the possibility of spray pyrolysis,the Ni-Co-W-containing oxide precursor presents a homogeneous distribution of metal elements,which is beneficial for the uniform substitution of W in the final materials.It was observed that with W substitution,the size of primary particles decreased from 338.06 to 71.76 nm,and cation disordering was as low as 3.34%.As a consequence,the pre-pared LNCW exhibited significantly improved electrochemical performance.Under optimal conditions,the lithium-ion battery assembled with LiNi_(0.9)Co_(0.0925)W_(0.0075)O_(2)(LNCW-0.75mol%)had an improved capacity retention of 82.7%after 200 cycles,which provides insight in-to the development of Ni-rich low-Co materials.This work presents that W can compensate for the loss caused by Co deficiency to a cer-tain extent.

HVOF-sprayed HAp/S53P4 BG composite coatings on an AZ31 alloy for potential applications in temporary implants

Bioactive thermal spray coatings produced via high-velocity oxygen fuel spray(HVOF)from hydroxyapatite(HAp)and bioactive glasses(BG)have the potential to be employed on temporary implants due to the ability of both HAp and BG to dissolve and promote osseointegration,considering that both phases have different reaction and dissolution rates under in-vitro conditions.In the present work,75%wt.HAp-25%wt.S53P4 bioactive glass powders were HVOF-sprayed to obtain HAp/S53P4 BG composite coatings on a bioresorbable AZ31 alloy.The study is focused on exploring the effect of the stand-off distance and fuel/oxygen ratio variation as HVOF parameters to obtain stable structural coatings and to establish their effect on the phases and microstructure produced in those coatings.Different characterization techniques,such as scanning electron microscopy,X-ray diffraction,and Fourier transform infrared spectroscopy,were employed to characterize relevant structural and microstructural properties of the composite coatings.The results showed that thermal gradients during coating deposition must be managed to avoid delamination due to the high temperature achieved(max 550℃)and the differences in coefficients of thermal expansion.It was also found that both spraying distance and oxygen/fuel ratio allowed to keep the hydroxyapatite as the main phase in the coatings.In addition,in-vitro electrochemical studies were performed on the obtained HAp/S53P4 BG composite coatings and compared against the uncoated AZ31 alloy.The results showed a significant decrease in hydrogen evolution(at least 98%)when the bioactive coating was applied on the Mg alloy during evaluation in simulated body fluid(SBF).

Selective lithium recovery and regeneration of ternary cathode from spent lithium-ion batteries:Mixed HCl-H_(2)SO_(4) leaching-spray pyrolysis approach

The recycling of spent lithium-ion batteries(LIBs) is crucial for environmental protection and resource sustainability.However,the economic recovery of spent LIBs remains challenging due to low Li recovery efficiency and the need for multiple separation operations.Here,we propose a process involving mixed HCl-H_(2)SO_(4) leaching-spray pyrolysis for recycling spent ternary LIBs,achieving both selective Li recovery and the preparation of a ternary oxide precursor.Specifically,the process transforms spent ternary cathode(LiNi_(x)Co_yMn_(2)O_(2),NCM) powder into Li_(2)SO_(4) solution and ternary oxide,which can be directly used for synthesizing battery-grade Li_(2)CO_(3) and NCM cathode,respectively.Notably,SO_(4)^(2-) selectively precipitates with Li^(+) to form thermostable Li_(2)SO_(4) during the spray pyrolysis,which substantially improves the Li recovery efficiency by inhibiting Li evaporation and intercalation.Besides,SO_(2) emissions are avoided by controlling the molar ratio of Li^(+)/SO_(4)^(2-)(≥2:1),The mechanism of the preferential formation of Li_(2)SO_(4) is interpreted from its reverse solubility variation with temperature.During the recycling of spent NCM811,92% of Li is selectively recovered,and the regenerated NCM811 exhibits excellent cycling stability with a capacity retention of 81.7% after 300 cycles at 1 C.This work offers a simple and robust process for the recycling of spent NCM cathodes.

Experimental investigation on effective aerosol scavenging using different spray configurations with pre-injection of water mist for Fukushima Daiichi decommissioning

During the decommissioning of the Fukushima Daiichi nuclear power plant,it is important to consider the retrieval of resolidified debris both in air and underwater configurations.For the subsequent retrieval of debris from the reactor building,the resolidified debris must be cut into smaller pieces using various cutting methods.During the cutting process,aerosol particles are expected to be generated at the submicron scale.It has been noted that such aerosols sizing within the Greenfield gap(0.1-1μm)are difficult to remove effectively using traditional spraying methods.Therefore,to improve the aerosol removal efficiency of the spray system,a new aerosol agglomeration method was recently proposed,which involves injecting water mist to enlarge the sizes of the aerosol particles before removing them using water sprays.In this study,a series of experiments were performed to clarify the proper spray configurations for effective aerosol scavenging and to improve the performance of the water mist.The experimental results showed that the spray flow rate and droplet characteristics are important factors for the aerosol-scavenging efficiency and performance of the water mist.The results obtained from this study will be helpful for the optimization of the spray system design for effective aerosol scavenging during the decommissioning of the Fukushima Daiichi plant.

Structure and corrosion behavior of FeCoCrNiMo high-entropy alloy coatings prepared by mechanical alloying and plasma spraying

FeCoCrNiMox composite powders were prepared using the mechanical alloying technique and made into high-entropy alloy(HEA)coatings with the face-centered cubic phase using plasma spraying to address the element segregation problem in HEAs and pre-pare uniform HEA coatings.Scanning electron microscopy,transmission electron microscopy,and X-ray diffractometry were employed to characterize these coatings’microstructure and phase composition.The hardness,elastic modulus,and fracture toughness of coatings were tested,and the corrosion resistance was analyzed in simulated seawater.Results show that the hardness of the coating is HV0.1606.15,the modulus of elasticity is 128.42 GPa,and the fracture toughness is 43.98 MPa·m^(1/2).The corrosion potential of the coating in 3.5wt%NaCl solution is-0.49 V,and the corrosion current density is 1.2×10^(−6)A/cm^(2).The electrochemical system comprises three parts:the electrolyte,the adsorption and metallic oxide films produced during immersion,and the FeCoNiCrMo HEA coating.Over in-creasingly long periods,the corrosion reaction rate increases first and then decreases,the corrosion product film comprising metal oxides reaches a dynamic balance between formation and dissolution,and the internal reaction of the coating declines.

Simulation Study on the Heat Transfer Characteristics of a Spray-Cooled Single-Pipe Cooling Tower

The current study focuses on spray cooling applied to the heat exchange components of a cooling tower.An optimization of such processes is attempted by assessing different spray flow rates and droplet sizes.For simplicity,the heat exchanger of the cooling tower is modeled as a horizontal round tube and a cooling tower spray cooling model is developed accordingly using a computational fluid dynamics(CFD)software.The study examines the influence of varying spray flow rates and droplet sizes on the heat flow intensity between the liquid layer on the surface of the cylindrical tube and the surrounding air,taking into account the number of nozzles.It is observed that on increasing the spray flow strength,the heat flow intensity and extent of the liquid film in the system are enhanced accordingly.Moreover,the magnitude of droplet size significantly impacts heat transfer.A larger droplet size decreases evaporation in the air and enhances the deposition of droplets on the round tube.This facilitates the creation of the liquid film and enhances the passage of heat between the liquid film and air.Increasing the number of nozzles,while maintaining a constant spray flow rate,results in a decrease in the flow rate of each individual nozzle.This decrease is not favorable in terms of heat transfer.

Process Optimization of Cu-en/AP Composite Microspheres Preparation by Electrostatic Spray Method Based on ANSYS Simulation

To investigate the process optimizationof Cu-en/AP composite microspheres preparation via electrostatic spraying,and to reveal the effects of droplet properties and flow rate variations on the experimental results during the electrostatic spraying process,the prepared process parameters of Cu-en/AP composite microspheres by electrostatic spray method under the orthogonal experimental design simulated by ANSYS(Fluent).The influence of flow rate,solvent ratio,and solid mass on the experimental results is examined using a controlled variable method.The results indicate that under the conditions of a flow rate of 2.67×10^(-3)kg/s an acetone-to-deionized water ratio of 1.5∶1.0,and a solid mass of 200 mg,the theoretical particle size of the composite microspheres can reach e nanoscale.Droplet trajectories in the electric field remain stable without significant deviation.The simulation results show that particle diameter decreases with increasing flow rate,with the trend leveling off around a flow rate of 1×10^(-3)kg/s.As the solvent ratio increases(with higher acetone content),particle diameter initially decreases,reaching a minimum around a ratio of 1.5∶1.0 before gradually increasing.Increasing the solid mass also reduces the particle diameter,with a linear increase in diameter observed at around 220 mg.Cu-en/AP composite microspheres with nanoscale dimensions were confirmed under these conditions by the final SEM images.

Investigation of the Film Formation in Dynamic Air Spray Painting

To accurately predict the film thickness distribution during dynamic spraying performed with air guns and support accordingly the development of intelligent spray painting,the spray problem was analyzed numerically.In particular,the Eulerian-Eulerian approach was employed to calculate the paint atomization and film deposition process.Different spray heights,spray angles,spray gun movement speeds,spray trajectory curvature radii,and air pressure values were considered.Numerical simulation results indicate that the angle of spray painting significantly affects the velocity of droplets near the spray surface.With an increase in the spraying angle,spraying height and spray gun movement speed,the maximum film thickness decreases to varying degrees,and the uniformity of the film thickness also continuously worsens.When the spray gun moves along an arc trajectory,at smaller arc radii,the film thickness on the inside of the arc is slightly greater than that on the outside,but the impact on the maximum film thickness is minimal.Increasing air pressure expands the coating coverage area,results in finer atomization of paint droplets,and leads to a thinner and a more uniform paint film.However,if the pressure is too high,it can cause paint splattering.Using the orthogonal experimental method,multiple sets of simulation calculations were conducted,and the combined effects of spraying height,spray angle,and spray gun movement speed on the film thickness distribution were comprehensively analyzed to determine optimal configurations.Finally,the reliability of the numerical simulations was validated through dynamic spray painting experiments.

Effects of plasma spraying process on microstructure and mechanical properties of Cr_(2)AlC/410 composite coatings

To investigate the influences of Cr_(2)AlC mass fraction and supersonic plasma spraying process on the microstructure and mechanical properties of Cr_(2)AlC reinforced 410 stainless steel composite coatings,the coatings containing different mass fractions of Cr_(2)AlC were prepared and investigated.The composite coating exhibited low porosity and high adhesion strength.The addition of Cr_(2)AlC significantly enhanced the hardness of the composite coatings through particle strengthening.However,when the mass fraction of Cr_(2)AlC was 20%,the aggregation of Cr_(2)AlC resulted in a strong decrease in the coating preparation efficiency,as well as a decline in adhesion strength.In the supersonic plasma spraying process,the Ar flow rate mainly influenced the flight velocity of the particles,while the H_(2) flow rate and the current mainly affected the temperature of the plasma torch.Consequently,all of them influenced the melting degree of particles and the quality of the coating.The lowest porosity and the highest hardness and adhesion strength could be obtained when the Ar flow rate is 125 L/min,the H_(2) flow rate is 25 L/min,and the current is 385 A.

Effect of cold rolling deformation on microstructure evolution and mechanical properties of spray formed Al−Zn−Mg−Cu−Cr alloys

The impact of cold rolling deformation,which was introduced after solid solution and before aging treatment,on microstructure evolution and mechanical properties of the as-extruded spray formed Al−9.8Zn−2.3Mg−1.73Cu−0.13Cr(wt.%)alloy,was investigated.SEM,TEM,and EBSD were used to analyze the microstructures,and tensile tests were conducted to assess mechanical properties.The results indicate that the D1-T6 sample,subjected to 25%cold rolling deformation,exhibits finer grains(3.35μm)compared to the D0-T6 sample(grain size of 4.23μm)without cold rolling.Cold rolling refines the grains that grow in solution treatment.Due to the combined effects of finer and more dispersed precipitates,higher dislocation density and smaller grains,the yield strength and ultimate tensile strength of the D1-T6 sample can reach 663 and 737 MPa,respectively.In comparison to the as-extruded and D0-T6 samples,the yield strength of the D1-T6 sample increases by 415 and 92 MPa,respectively.

Preparation and Properties of Spray Polyurea Elastomer for Aquaculture Foam Floating Balls

[Objectives] This study was conducted to develop a polyurea elastomer which can be sprayed on the surface of expanded polystyrene (EPS) floating balls, so as to improve the surface strength and service life of the floating balls. [Methods] The effects of the types and amounts of isocyanate, chain extenders and polyether polyols on the gelation rate, adhesion and wear resistance of polyurea elastomer were investigated, and it was finally determined the preparation process of polyurea elastomer using liquid isophorone diisocyanate (IPDI) and amino-terminated polyether (D2000) as the main raw materials, dimethylthiotoluene diamine (E300) as the chain extender and silica as the wear resistance modifier through two-step solution polymerization of prepolymerization and chain extension. [Results] The physical properties and chemical resistance tests of spray polyurea elastomer showed that it had good physical properties and acid and alkali resistance, and could meet the requirements of spraying and protection of EPS floating ball surface in marine environment. [Conclusions] Polyurea elastomer coating can improve the aging resistance, wear resistance and acid and alkali resistance of EPS floating balls, and prevent them from being fragile and floating randomly to form marine floating garbage which results in "white pollution".

Effect of Spray Rails on Takeoff Performance of Amphibian Aircraft

Amphibian aircraft have seen a rise in popularity in the recreational and utility sectors due to their ability to take off and land on both land and water, thus serving a myriad of purposes, such as aerobatics, surveillance, and firefighting. Such seaplanes must be aerodynamically and hydrodynamically efficient, particularly during the takeoff phase. Naval architects have long employed innovative techniques to optimize the performance of marine vessels, including incorporating spray rails on hulls. This research paper is dedicated to a comprehensive investigation into the potential utilization of spray rails to enhance the takeoff performance of amphibian aircraft. Several spray rail configurations obtained from naval research were simulated on a bare Seamax M22 amphibian hull to observe an approximate 10% - 25% decrease in water resistance at high speeds alongside a 3% reduction in the takeoff time. This study serves as a motivation to improve the design of the reference airplane hull and a platform for detailed investigations in the future to improve modern amphibian design.

Designing an Experimental Device for Swinging Excitation Spray Cooling

In this paper,we introduce the design principle of the oscillating excited spray cooling experimental device.We then designed an oscillating excited spray cooling experimental device.By using the device,the swaying motion can be realized through the control system,and the motion of the droplet under different vibration frequencies can be observed.By measuring the liquid flow rate and pressure,the changes in liquid flow rate,pressure,and temperature with time under different vibration frequencies were studied.The trajectory of the droplet and the temperature distribution of the droplet under different vibration frequencies could be observed.The device has a simple structure,is easy to control,and can achieve continuous observation of the spray cooling process.

Effect of TiB_2 addition on microstructure of spray-formed Si-30Al composite

An in situ reaction and spray forming technique were employed in the synthesis of 2% TiB2/Si-30Al composite.The formation mechanism of TiB2 particulates was explained based on thermodynamic theory.The modification of the primary Si in the Si-30Al alloy was interpreted in the light of the knowledge of atomic diffusion.The experimental results show that adding 2% TiB2 to the Si-30Al alloy can effectively refine the primary Si.Moreover,the coarsening and growth of primary Si phase in its semi-solid state was retarded effectively due to the existence of the TiB2 particulates.