Assessment of Lubrication Property and Machining Performance of Nanofluid Composite Electrostatic Spraying(NCES)Using Different Types of Vegetable Oils as Base Fluids of External Fluid

The current study of minimum quantity lubrication(MQL)concentrates on its performance improvement.By contrast with nanofluid MQL and electrostatic atomization(EA),the proposed nanofluid composite electrostatic spraying(NCES)can enhance the performance of MQL more comprehensively.However,it is largely influenced by the base fluid of external fluid.In this paper,the lubrication property and machining performance of NCES with different types of vegetable oils(castor,palm,soybean,rapeseed,and LB2000 oil)as the base fluids of external fluid were compared and evaluated by friction and milling tests under different flow ratios of external and internal fluids.The spraying current and electrowetting angle were tested to analyze the influence of vegetable oil type as the base fluid of external fluid on NCES performances.The friction test results show that relative to NCES with other vegetable oils as the base fluids of external fluid,NCES with LB2000 as the base fluid of external fluid reduced the friction coefficient and wear loss by 9.4%-27.7%and 7.6%-26.5%,respectively.The milling test results display that the milling force and milling temperature for NCES with LB2000 as the base fluid of external fluid were 1.4%-13.2%and 3.6%-11.2%lower than those for NCES with other vegetable oils as the base fluids of external fluid,respectively.When LB2000/multi-walled carbon nanotube(MWCNT)water-based nanofluid was used as the external/internal fluid and the flow ratio of external and internal fluids was 2:1,NCES showed the best milling performance.This study provides theoretical and technical support for the selection of the base fluid of NCES external fluid.

Design and test of a six-rotor unmanned aerial vehicle(UAV)electrostatic spraying system for crop protection

In recent years,multi-rotor unmanned aerial vehicle(UAV)crop protection operations have experienced tremendous growth.Compared with manual operations,they have advantages such as high operational efficiency,small pesticide dosage,and low pesticide hazards for humans.However,the tiny droplets produced during UAV spraying for crop protection are affected by the rotor air flow and will drift in all directions in an uncontrollable manner,severely affecting the pesticide deposition pattern and resulting in pesticide waste.To improve pesticide use efficiency during multi-rotor UAV spraying,an electrostatic spray system was designed based on electrostatic spray technology and a six-rotor UAV.The proper operation parameters for the UAV electrostatic spray were determined by test,which were spray altitude of 50 cm above the crop,spray pressure of 0.3 MPa and charging voltage of 9 kV.Field test was performed based on these parameters.The results showed that compared with non-electrostatic spray,the electrostatic spray improved by 13.6%in the average deposition density above the sampling device and 32.6%in the middle.The research can provide a reference for designing multi-rotor UAV electrostatic spray devices.

CALCULATION AND EXPERIMENTAL INVESTIGATION OF ELECTRIC FIELDS INDUCED BY ELECTRODES IN ELECTROSTATIC CHARGED POWDER SPRAYING TECHNIQUE

Electric fields induced by ring and pin electrodes in electrostatic charged powder sprayingtechnique are analysed. The fundamental formulae to deseribe these fields have been built up. Theseformulae could be used to design electrostatic charged podwer spraying system. The chargingeffectiveness of ring and pin electrode is experimentally investigated and compared each other. Theperformance of ring electrode is better than that of pin electrode.

Experimental Study on Grinding Force of Electrostatic Coated Grinding Wheel

In order to deal with the hard machining of TC4 alloy,coated graphite on grinding wheel surface by electrostatic device is proposed in this paper.This paper mainly completed the design of graphite electrostatic spraying grinding wheel device,force experimental analysis of grinding TC4 alloy with coated graphite grinding wheel,and summary of the influence of different grinding speeds and grinding depths on grinding force and grinding force ratio.The experimental results show that the lubrication coating can reduce the grinding force and grinding force ratio in the process of grinding TC4 alloy with graphite powder-coated wheel under electrostatic field force,compared to dry grinding with the uncoated wheel.

Investigation of Electrostatic Atomization and Its Application for the Synthesis of Fine Ceramic Powder

In the present study,electrostatic atomization(EA)behavior of several test liquids having much higher viscosities(1 400 mPa·s)than have previously been studied was investigated by spraying at a series of applied voltages and flow rates.The results showed that to obtain stable cone-jet mode spraying and hence gain better monodispersity of droplets,electrical conductivity,viscosity and surface tension of the liquid are important controlling factors.The stable cone-jet mode could be easily established for liquids having shear viscosities in the range from 80 to 1 400 mPa·s and surface tensions below 65 mN·m-1.In contrast,methylcellulose aqueous solutions with shear viscosities ranging from 10 to 540 mPa·s and moderate surface tensions(50~56 mN·m-1)generated more complicated spraying modes.However,fine TiO2 powder(a few micrometers in size)could be prepared using the EA method from its precursor solutions.

Review of electrostatic system parameters,charged droplets characteristics and substrate impact behavior from pesticides spraying

Electrostatic spraying application is adopted in crop protection to prevent pest infestation,to improve product quality and to maximize yield.It involves a superposition of charges to pesticide spray droplets to attract substrate ions at obscured surfaces.The droplets wraparound effect reduces off-target deposition,enhances on-target spray and invariably improves spray efficiency.Electrostatic spraying system works effectively at optimum parameters in combination with charging voltages,application pressures,spraying height regimes,flow rate,travel speed,electrode material,and nozzle orientation.Many combinations of the system parameter settings have been systematically used by researchers for the electrostatic application,but there are unknown specific optimum parameters combinations for pesticide spraying.Since droplets chargeability influences the effectiveness of electrostatic spraying system,the parameters that produce ideal charge to mass ratio determine the functionality of the spraying deposition,retention and surface coverage.This article,therefore,analyses electrostatic system parameters that produce suitably charged droplets characteristics for effective impacting behavior of pesticides on substrates.Increasing applied voltages consequently maximizes charge-mass ratio to optimum and starts declining upon further increase in voltages beyond a critical point.This review further proposes the selection of an optimum electrostatic parameters combination that yields optimum droplets chargeability in pesticide application.Also,it is necessary to investigate the charge property of substrates prior to pesticide application in order to superpose the right opposite charge on spray droplets at rupture time during electrostatic spraying system.

Pomegranate-inspired porous SnSe/ZnSe@C anode:A stress-buffer nanostructure for fast and ultrastable sodium-ion storage

Tin selenide(SnSe)is considered as a potential anode for sodium-ion batteries(SIBs)owing to its high theoretical specific capacity.Unfortunately,it suffers from drastic volume expansion/contraction during sodium ions insertion/extraction,resulting in poor cycling stability.Herein,a pomegranate-inspired porous carbon shell wrapped heterogeneous SnSe/ZnSe composite(SnSe/ZnSe@C)is exquisitely designed and fabricated through electrostatic spraying followed by high-temperature selenization.The polyacrylonitrile-derived carbon shell acts as an adhesive to link the porous cubic SnSe/ZnSe and form highly interconnected microcircuits to improve the electron/ion transfer efficiency and inhibit the bulk volume change of internal metallic selenide nanoparticles and polyselenides dissolution during repeated cycling.Moreover,the abundant heterostructure interface of SnSe/ZnSe further significantly accelerates the electrons/ions transport.As a result,the as-prepared SnSe/ZnSe@C electrode exhibits a high specific capacity(508.3 m Ah g^(-1)at 0.05 A g^(-1)),excellent rate performance(177.8 m Ah g^(-1)at 10.0 A g^(-1)),and remarkable cycling stability(195.9 m Ah g^(-1)after 10,000 cycles at 5.0 A g^(-1)).Furthermore,in-situ Xray diffraction(XRD)/Raman,ex-situ transmission electron microscopy,and kinetic analysis clearly reveal a four-step electrochemical reaction process and battery-capacitor dual-mode sodium storage mechanism.This work provides a new perspective for developing commercial SIBs anode materials with high capacity and long lifespan.

Design and performance test of a novel UAV air-assisted electrostatic centrifugal spraying system

In order to improve the deposition and uniformity of the pesticide sprayed by the agricultural spraying drone,this study designed a novel spraying system,combining air-assisted spraying system with electrostatic technology.First,an air-assisted electrostatic centrifugal spray system was designed for agricultural spraying drones,including a shell,a diversion shell,and an electrostatic ring.Then,experiments were conducted to optimize the setting of the main parameters that affect the charge-to-mass ratio,and outdoor spraying experiments were carried out on the spraying effect of the air-assisted electrostatic centrifugal spray system.The results showed the optimum parameters were that the centrifugal rotation speed was 10000 r/min,the spray pressure was 0.3 MPa,the fan rotation speed was 14000 r/min,and the electrostatic generator voltage was 9 kV;The optimum charge-to-mass ratio of the spray system was 2.59 mC/kg.The average deposition density of droplets on the collecting platform was 366.1 particles/cm^(2) on the upper layer,345.1 particles/cm^(2) on the middle layer,and 322.5 particles/cm^(2) on the lower layer.Compared to the results of uncharged droplets on the upper,middle,and lower layers,the average deposition density was increased by 34.9%,30.4%,and 30.2%,respectively,and the uniformity of the distribution of the droplets at different collection points was better.

Adaptable "bubble particles" prepared by green aqueous phase reshaping for completely removing odor

Facile and ecofriendly loading of micro/nano function-specific substances to create functional materials is a trend being pursued by researchers.However,current micro/nano particles loading approaches are often hindered by issues such as uneven distribution,unsatisfactory stability and complicate procedure.In this work,we present an aqueous phase reshaping method that only utilizes the moisture to fabricate the"bubble particles",which could perfectly cater to the topography of the substrate.The green preparation of bubble particles adopts an absolutely zero-pollution method,realizing the firm loading of particles on the substrate.Integrating the preparation and loading of particles overcomes the traditional complicate process,while the aqueous phase reshaping ensures uniform and firm loading of the"bubble particles"onto the substrate.Our mechanism demonstrates a significant enhancement in the interface relation after aqueous phase reshaping,with a 121-fold increase in contact surface area achieved by reducing the height by 1μm.Furthermore,we explore for the first time the influence of the nature of the receiving substrate on the interface morphology of particles during electrostatic spraying,which has important guiding significance for the interface relationship of electrostatic spraying and even electrostatic spinning materials.We also screen out the natural antibacterial essential oil linalool as the effective specialized antibacterial agent,which can specifically inhibit the odor-producing Proteus in urine,with an antibacterial rate of up to 100%.Taken together,this simple,ecofriendly method for fabricating functional materials with optimal interface stability appears highly promising for use in various products formed by electrostatic spraying/spinning.

Wear Resistance, Cytotoxicity and Antibacterial Properties of Polyetheretherketone Composite Modified by Carbon Fiber and Black Phosphorus

High wear resistance,low cytotoxicity and excellent antibacterial properties are the basis for osseointegration of implant materials.Polyetheretherketone(PEEK)has been considered as a potential implant material due to its excellent biocompatibility,natural radiolucency and mechanical properties.In this work,to improve the wear resistance,cytotoxicity and antibacterial properties of PEEK,carbon fiber(CFR)and Black Phosphorus(BP)were used to synergistically modify PEEK by two methods,deposition of BP coating on CFR-PEEK and BP/CFR-PEEK coating on Ti6Al4V(TC4)through electrostatic spraying.After CFR and BP synergistically modified PEEK,the friction coefficient of BP coating on CFR-PEEK and BP/CFR-PEEK coating were 0.14±0.01 and 0.09±0.02,respectively.The wear volume of BP coating on CFR-PEEK(30.54±1.32)was higher than that of BP/CFR-PEEK coating(9.46±1.32),which indicated that BP/CFR-PEEK coating showed high wear resistance.The difference in wear resistance may be caused by the fact that BP was not easily oxidized in BP/CFR-PEEK coating.In addition,BP coating on CFR-PEEK and BP/CFR-PEEK coating showed no obvious cytotoxicity to L929 cell and presented excellent antibacterial efficiency(up to 94.5%±2.8%and 96.0%±3.8%,respectively)against Staphylococcus aureus(S.aureus).It was concluded that BP/CFR-PEEK coating exhibited high wear resistance,low cytotoxicity and excellent antibacterial properties against S.aureus,which might provide a foundation for osseointegration of implants.