Unmanned agricultural aircraft system(UAAS)hasbeen widely employed as a low-cost and reliable method to apply agrochemicals to small agricultural fields in China.The performance of battery-poweredmultirotor UAAS has a...Unmanned agricultural aircraft system(UAAS)hasbeen widely employed as a low-cost and reliable method to apply agrochemicals to small agricultural fields in China.The performance of battery-poweredmultirotor UAAS has attracted considerable attention from manufacturers and researchers.The objective of this research was to design a UAAS equippingwith a data acquisition system,to characterize its chemical application performance based on droplet deposition data and optimize the operating parameters.Each test was repeated three times to assess the reliability of the spraying system.Various flight parameters were also evaluated.The optimal spray pressure for the XR8001 and XR8002(TeeJet,Wheaton,IL,USA)nozzles was found to be 300 kPa,and the latter nozzle had a higher droplet deposition rate and spray volume.Spray volume was not significantly affected by the flight speed or droplet density and was negatively correlated with the nozzle pressure.The results of this study provide a basis for improving the efficiency of UAAS chemicalapplication systems in terms of large-scale application.展开更多
With the rapid growth of coal chemical industry in China, the selection and application of Air Separation Unit(ASU) became very important. As the core unit in coal chemical industry, ASU will greatly impact the engine...With the rapid growth of coal chemical industry in China, the selection and application of Air Separation Unit(ASU) became very important. As the core unit in coal chemical industry, ASU will greatly impact the engineering construction and operation/production of coal chemical business. In this paper, major suppliers of ASU at home and abroad were reviewed, and the major supplying status of ASU in China was introduced. The ASUs in operation of SINOPEC were listed and discussed. On this basis, some suggestions of ASU selection strategies were provided on localization, standardization and operation methods.展开更多
This paper studied the effect of reducing application of chemical fertilizer,increasing application of functional organic fertilizer and trace elements and fully using biological pesticides on physiological traits,yie...This paper studied the effect of reducing application of chemical fertilizer,increasing application of functional organic fertilizer and trace elements and fully using biological pesticides on physiological traits,yield and quality of radish. The results showed that applying functional organic fertilizer and trace elements and fully using biological pesticides could help to significantly improve the radish fleshy root yield,increase soluble sugar and vitamin C content,reduce crude fiber and nitrate content,but had no significant influence on radish moisture content,glucosinolates and chlorpyrifos content in organophosphorus pesticides.展开更多
This study investigates the potential of metal additives in acrylonitrile butadiene styrene(ABS)polymer fuel to enhance hybrid rocket motor(HRM)performance through computational analysis,Chemical Equilibrium with Appl...This study investigates the potential of metal additives in acrylonitrile butadiene styrene(ABS)polymer fuel to enhance hybrid rocket motor(HRM)performance through computational analysis,Chemical Equilibrium with Applications(CEA),software.ABS was selected as the base fuel due to its thermoplastic nature,which allows for the creation of complex fuel geometries through 3D printing,offering significant flexibility in fuel design.Hybrid rockets,which combine a solid fuel with a liquid oxidiser,offer advantages in terms of operational simplicity and safety.However,conventional polymer fuels often exhibit low regression rates and suboptimal combustion efficiencies.In this research,we evaluated a range of metal additives-aluminium(Al),boron(B),nickel(Ni),copper(Cu),and iron(Fe)-at chamber pressures ranging from 1 to 30 bar and oxidiser-to-fuel(O/F)ratios between 1.1 and 12,resulting in 1800 unique test conditions.The main performance parameters used to assess each formulation were characteristic velocity(C^(*))and adiabatic flame temperature.The results revealed that each test produced a different optimum O/F ratio,with most ratios falling between 4 and 6.The highest performance was achieved at a chamber pressure of 30 bar across all formulations.Among the additives,Al and B demonstrated significant potential for improved combustion performance with increasing metal loadings.In contrast,Fe,Cu,and Ni reached optimal performance at a minimum loading of 1%.Future work includes investigating B-Al metal composites as additives into the ABS base polymer fuel,and doing experimental validation tests where the metallised ABS polymer fuel is 3D printed.展开更多
Traditional Chinese Medicine(TCM)has been used in prevention and treatment of disease in clinical practice for thousands of years,with an indispensable role of multiple ingredients.Thus,a rapid and effective chemical ...Traditional Chinese Medicine(TCM)has been used in prevention and treatment of disease in clinical practice for thousands of years,with an indispensable role of multiple ingredients.Thus,a rapid and effective chemical ingredients analysis was of necessary to be established for the evaluation of the holistic quality of TCM.As could afford the data with high resolution and high sensitivity,展开更多
The agrochemical applicationwith conventional sprayers results inwastage of applied chemicals,which not only increases the economic losses but also pollutes the environment.In order to overcome these drawbacks,an imag...The agrochemical applicationwith conventional sprayers results inwastage of applied chemicals,which not only increases the economic losses but also pollutes the environment.In order to overcome these drawbacks,an image processing based real-time variable-rate chemical spraying systemwas developed for the precise application of agrochemicals in diseased paddy crop based on crop disease severity information.The developed system comprised ofweb cameras for image acquisition,laptop for image processing,microcontroller for controlling the system functioning,and solenoid valve assisted spraying nozzles.The chromatic aberration(CA)based image segmentation method was used to detect the diseased region of paddy plants.The system further calculated the disease severity level of paddy plants,based onwhich the solenoid valves remained on for a specific timeduration so that the required amount of agrochemical could be sprayed on the diseased paddy plants.Field performance of developed sprayer prototype was evaluated in the variable-rate application(VRA)and constant-rate application(CRA)modes.The field testing results showed a minimum 33.88%reduction in applied chemical while operating in the VRA mode as compared with the CRA mode.Hence,the developed systemappears promising and could be used extensively to reduce the cost of pest management as well as to control environmental pollution due to such agrochemicals.展开更多
Metal-free carbon catalysts are promising alternatives to noble-metal electrocatalysts for H_(2)O_(2) production through two electron oxygen reduction reaction(2e−ORR).Herein,a novel bioengineering approach is propose...Metal-free carbon catalysts are promising alternatives to noble-metal electrocatalysts for H_(2)O_(2) production through two electron oxygen reduction reaction(2e−ORR).Herein,a novel bioengineering approach is proposed to prepare N-doped hollow carbon nanoboxes from guanine precursor.The optimized NC-HNBs-550 exhibits an exceptional electrocatalytic performance,achieving a high H_(2)O_(2) Faradaic efficiency(FE)of over 90%across a broad potential window exceeding 0.6 V.Remarkably,when tested in a flow cell configuration,NC-HNBs-550 delivers near-unity FE for H_(2)O_(2) production at industrial-grade current densities,demonstrating its practicality for scalable applications.Impressively,the in situ electro-synthesized H_(2)O_(2) is further employed as a green oxidant for rapid degradation of various organic dyes and even tetracyclines,and high-purity benzoyl peroxide(BPO)synthesis,highlighting its versatility in environmental and chemical applications.Combining experimental and theoretical analyses,we reveal that the superior 2e−ORR activity originates from the abundance of pyrrolic-N species in NC-HNBs,which optimize the adsorption energy of*OOH intermediates and promote selective O_(2) reduction.This work not only advances the rational design of biomass-derived carbon catalysts for sustainable H_(2)O_(2) production but also provides a versatile platform for environmental remediation and value-added chemical production.展开更多
Hybrid rocket engines have gathered significant attention due to their ease of use,safety,and affordability associated with traditional chemical propulsion systems.They offer the advantage of on-demand throttle and th...Hybrid rocket engines have gathered significant attention due to their ease of use,safety,and affordability associated with traditional chemical propulsion systems.They offer the advantage of on-demand throttle and thrust adjustments.The performance of hybrid rocket engines depends on the regression rate,which is the transition of the solid fuel grain to flammable gas.Unlike solid and liquid engines,hybrids experience varying oxidizer-to-fuel(O/F)ratios over time.Factors such as changes in oxidizer flow and fuel port diameter contribute to this fluctuation,leading to incomplete combustion and reduced efficiency.To enhance hybrid rocket engine performance,ongoing research explores various methods.One approach is increasing the oxidizer flow velocity over the burning fuel surface.This paper employs analytical and numerical techniques to determine the effective oxidizer/fuel ratio for a single-port fuel grain in a hybrid rocket engine.Ultimately,the research aims to optimize performance,allowing this secure and efficient propulsion technology to mature.展开更多
A smart sprayer comprises a detection system and a chemical spraying system.In this study,the development status and challenges of the detection systems of smart sprayers are discussed along with perspectives on these...A smart sprayer comprises a detection system and a chemical spraying system.In this study,the development status and challenges of the detection systems of smart sprayers are discussed along with perspectives on these technologies.The detection system of a smart sprayer is used to collect information on target areas and make spraying decisions.The spraying system controls sprayer operation.Various sensing technologies,such as machine vision,spectral analysis,and remote sensing,are used in target detection.In image processing,morphological features are employed to segment characteristics such as shape,structure,color,and pattern.In spectral analysis,the characteristics of reflectance and multispectral images are applied in crop detection.For the remote sensing application,vegetation indices and hyperspectral images are used to provide information on crop management.Other sensors,such as thermography,ultrasonic,laser,and X-ray sensors,are also used in the detection system and mentioned in the review.On the basis of this review,challenges and perspectives are suggested.The findings of this study may aid the understanding of smart sprayer systems and provide feasible methods for improving efficiency in chemical applications.展开更多
A hybrid rocket engine test bench experiment carried out the thrust 300 N,retaining nitrous gas as an oxidant,and 70 weight percent paraffin and 30 weight percent aluminum as fuel.To enhance the regression rate,new fu...A hybrid rocket engine test bench experiment carried out the thrust 300 N,retaining nitrous gas as an oxidant,and 70 weight percent paraffin and 30 weight percent aluminum as fuel.To enhance the regression rate,new fuels such as paraffin-based fuel have been created,allowing for more compact engine designs with high thrust densities.As a result,the use of hybrid rocket engines in several domains,such as sounding rockets and small satellites for educational purposes and launch vehicle propulsion systems,has become possible.The solid fuel grain diameter is assumed to spread the characterization under different conditions.Estimate the rocket performance in the assumed condition and develop the test bench setup.In this paper,the data are composed of a 165 mm length of grain,external diameter is 79.6 mm and internal/port diameter is 8 mm.The injector plate used in this experiment is three injector holes with 120°.This injector is a showerhead that is simple in design and it is frequently used in hybrid rocket engines.Constraints such as the pressure in the combustion chamber being 50 bar and the SS304 nozzle,thrust were measured.Four separate test series were conducted.In the first test,one hole in the showerhead injector geometry was studied.In the 2nd,3rd,and 4th tests,injector plates with three injector holes were used.The test bench of a hybrid rocket engine has many components(oxidizer/pressure tank,combustion chamber with the pre-combustion,post-combustion chamber,conical shape nozzle,igniter,injector plate,etc.).展开更多
With the advent of new technologies in space science,numerous missions and programs to launch satellites of various scales have received significant attention in the scientific community.However,there are a few comple...With the advent of new technologies in space science,numerous missions and programs to launch satellites of various scales have received significant attention in the scientific community.However,there are a few complexities involved to encourage activities such as space tourism and exploration due to the technical constraints that the launch vehicle poses.To surmount these challenges,a novel hybrid rocket engine must be designed which allows us to tailor the characteristics during its endurance simulations.In the current work,we have investigated the propellant’s thermal and flow characteristics such as glass transition and melting temperature,specific impulse,characteristic velocity,regression rate,and thrust,respectively,without compromising the performance of likewise liquid propellant engine.In the current work,we investigated propellant characteristics for pure paraffin wax with oxidizers,such as liquid oxygen and nitrous oxide,and pure paraffin with additives of aluminum,magnesium,and oxidizers.It was observed that pure paraffin with liquid oxygen and additive aluminum(30%weight)resulted in the highest specific impulse among other combinations,whereas differential scanning calorimeter investigations reported a reduction in latent heat with the increase in weight%of paraffin and aluminum powder.It is also suggested that heat flow at 10%weight complies with the hybrid rocket engine.展开更多
Recent development in space mission demands safer and more cost-effective space missions.Hybrid rocket engine technological advancements have prolonged a critical stage in their development and it is the better option...Recent development in space mission demands safer and more cost-effective space missions.Hybrid rocket engine technological advancements have prolonged a critical stage in their development and it is the better option for such space missions,as it has a lot of advantages over the solid rocket motor and liquid rocket engine.It is simple in design,has high thrust density,low weight,and is safer than a liquid rocket engine.It has restarted capability,safe,low explosion risk,and high specific impulse than a solid rocket motor.This paper shows the numerical analysis of a hybrid rocket engine.The paper highlights the initial boundary conditions in the analysis of a 300-N hybrid rocket engine.The process started with a chemical kinematic examination of engine-compatible fuels and oxidizers.This investigation provided the fundamental parameters required for the design and subsequent dimensioning of a hybrid rocket engine.It also produced a three-dimensional design model,performed numerical analysis using ANSYS software,and validated the findings using existing literature.Using the k-εturbulence model and transient solver on 8 mm port diameter for analyzing.The computational fluid dynamics model offered the qualities of a real hybrid rocket engine and it will be helpful to researchers and the scientific community in the future.展开更多
基金This work was partially financially supported by the National Key Research and Development Program of China(Grant No.2016YFD0200701).
文摘Unmanned agricultural aircraft system(UAAS)hasbeen widely employed as a low-cost and reliable method to apply agrochemicals to small agricultural fields in China.The performance of battery-poweredmultirotor UAAS has attracted considerable attention from manufacturers and researchers.The objective of this research was to design a UAAS equippingwith a data acquisition system,to characterize its chemical application performance based on droplet deposition data and optimize the operating parameters.Each test was repeated three times to assess the reliability of the spraying system.Various flight parameters were also evaluated.The optimal spray pressure for the XR8001 and XR8002(TeeJet,Wheaton,IL,USA)nozzles was found to be 300 kPa,and the latter nozzle had a higher droplet deposition rate and spray volume.Spray volume was not significantly affected by the flight speed or droplet density and was negatively correlated with the nozzle pressure.The results of this study provide a basis for improving the efficiency of UAAS chemicalapplication systems in terms of large-scale application.
文摘With the rapid growth of coal chemical industry in China, the selection and application of Air Separation Unit(ASU) became very important. As the core unit in coal chemical industry, ASU will greatly impact the engineering construction and operation/production of coal chemical business. In this paper, major suppliers of ASU at home and abroad were reviewed, and the major supplying status of ASU in China was introduced. The ASUs in operation of SINOPEC were listed and discussed. On this basis, some suggestions of ASU selection strategies were provided on localization, standardization and operation methods.
基金Supported by the Second Batch of Modern Agricultural Industry Technology System Project in Hubei Province
文摘This paper studied the effect of reducing application of chemical fertilizer,increasing application of functional organic fertilizer and trace elements and fully using biological pesticides on physiological traits,yield and quality of radish. The results showed that applying functional organic fertilizer and trace elements and fully using biological pesticides could help to significantly improve the radish fleshy root yield,increase soluble sugar and vitamin C content,reduce crude fiber and nitrate content,but had no significant influence on radish moisture content,glucosinolates and chlorpyrifos content in organophosphorus pesticides.
文摘This study investigates the potential of metal additives in acrylonitrile butadiene styrene(ABS)polymer fuel to enhance hybrid rocket motor(HRM)performance through computational analysis,Chemical Equilibrium with Applications(CEA),software.ABS was selected as the base fuel due to its thermoplastic nature,which allows for the creation of complex fuel geometries through 3D printing,offering significant flexibility in fuel design.Hybrid rockets,which combine a solid fuel with a liquid oxidiser,offer advantages in terms of operational simplicity and safety.However,conventional polymer fuels often exhibit low regression rates and suboptimal combustion efficiencies.In this research,we evaluated a range of metal additives-aluminium(Al),boron(B),nickel(Ni),copper(Cu),and iron(Fe)-at chamber pressures ranging from 1 to 30 bar and oxidiser-to-fuel(O/F)ratios between 1.1 and 12,resulting in 1800 unique test conditions.The main performance parameters used to assess each formulation were characteristic velocity(C^(*))and adiabatic flame temperature.The results revealed that each test produced a different optimum O/F ratio,with most ratios falling between 4 and 6.The highest performance was achieved at a chamber pressure of 30 bar across all formulations.Among the additives,Al and B demonstrated significant potential for improved combustion performance with increasing metal loadings.In contrast,Fe,Cu,and Ni reached optimal performance at a minimum loading of 1%.Future work includes investigating B-Al metal composites as additives into the ABS base polymer fuel,and doing experimental validation tests where the metallised ABS polymer fuel is 3D printed.
文摘Traditional Chinese Medicine(TCM)has been used in prevention and treatment of disease in clinical practice for thousands of years,with an indispensable role of multiple ingredients.Thus,a rapid and effective chemical ingredients analysis was of necessary to be established for the evaluation of the holistic quality of TCM.As could afford the data with high resolution and high sensitivity,
文摘The agrochemical applicationwith conventional sprayers results inwastage of applied chemicals,which not only increases the economic losses but also pollutes the environment.In order to overcome these drawbacks,an image processing based real-time variable-rate chemical spraying systemwas developed for the precise application of agrochemicals in diseased paddy crop based on crop disease severity information.The developed system comprised ofweb cameras for image acquisition,laptop for image processing,microcontroller for controlling the system functioning,and solenoid valve assisted spraying nozzles.The chromatic aberration(CA)based image segmentation method was used to detect the diseased region of paddy plants.The system further calculated the disease severity level of paddy plants,based onwhich the solenoid valves remained on for a specific timeduration so that the required amount of agrochemical could be sprayed on the diseased paddy plants.Field performance of developed sprayer prototype was evaluated in the variable-rate application(VRA)and constant-rate application(CRA)modes.The field testing results showed a minimum 33.88%reduction in applied chemical while operating in the VRA mode as compared with the CRA mode.Hence,the developed systemappears promising and could be used extensively to reduce the cost of pest management as well as to control environmental pollution due to such agrochemicals.
基金supported by the National Natural Science Foundation of China(Nos.22372039 and 22305247)the Natural Science Foundation of Fujian Province of China(No.2021J06010)the Fuzhou University Testing Fund of precious apparatus(No.2025T022).
文摘Metal-free carbon catalysts are promising alternatives to noble-metal electrocatalysts for H_(2)O_(2) production through two electron oxygen reduction reaction(2e−ORR).Herein,a novel bioengineering approach is proposed to prepare N-doped hollow carbon nanoboxes from guanine precursor.The optimized NC-HNBs-550 exhibits an exceptional electrocatalytic performance,achieving a high H_(2)O_(2) Faradaic efficiency(FE)of over 90%across a broad potential window exceeding 0.6 V.Remarkably,when tested in a flow cell configuration,NC-HNBs-550 delivers near-unity FE for H_(2)O_(2) production at industrial-grade current densities,demonstrating its practicality for scalable applications.Impressively,the in situ electro-synthesized H_(2)O_(2) is further employed as a green oxidant for rapid degradation of various organic dyes and even tetracyclines,and high-purity benzoyl peroxide(BPO)synthesis,highlighting its versatility in environmental and chemical applications.Combining experimental and theoretical analyses,we reveal that the superior 2e−ORR activity originates from the abundance of pyrrolic-N species in NC-HNBs,which optimize the adsorption energy of*OOH intermediates and promote selective O_(2) reduction.This work not only advances the rational design of biomass-derived carbon catalysts for sustainable H_(2)O_(2) production but also provides a versatile platform for environmental remediation and value-added chemical production.
文摘Hybrid rocket engines have gathered significant attention due to their ease of use,safety,and affordability associated with traditional chemical propulsion systems.They offer the advantage of on-demand throttle and thrust adjustments.The performance of hybrid rocket engines depends on the regression rate,which is the transition of the solid fuel grain to flammable gas.Unlike solid and liquid engines,hybrids experience varying oxidizer-to-fuel(O/F)ratios over time.Factors such as changes in oxidizer flow and fuel port diameter contribute to this fluctuation,leading to incomplete combustion and reduced efficiency.To enhance hybrid rocket engine performance,ongoing research explores various methods.One approach is increasing the oxidizer flow velocity over the burning fuel surface.This paper employs analytical and numerical techniques to determine the effective oxidizer/fuel ratio for a single-port fuel grain in a hybrid rocket engine.Ultimately,the research aims to optimize performance,allowing this secure and efficient propulsion technology to mature.
基金supported by the National Natural Science Foundation of China(Project No.U0931001,31071330)the 863 Program(2012BAH29 B04,2012AA101901)the Science Research Foundation for Young Teachers(Project No.2011JS151)。
文摘A smart sprayer comprises a detection system and a chemical spraying system.In this study,the development status and challenges of the detection systems of smart sprayers are discussed along with perspectives on these technologies.The detection system of a smart sprayer is used to collect information on target areas and make spraying decisions.The spraying system controls sprayer operation.Various sensing technologies,such as machine vision,spectral analysis,and remote sensing,are used in target detection.In image processing,morphological features are employed to segment characteristics such as shape,structure,color,and pattern.In spectral analysis,the characteristics of reflectance and multispectral images are applied in crop detection.For the remote sensing application,vegetation indices and hyperspectral images are used to provide information on crop management.Other sensors,such as thermography,ultrasonic,laser,and X-ray sensors,are also used in the detection system and mentioned in the review.On the basis of this review,challenges and perspectives are suggested.The findings of this study may aid the understanding of smart sprayer systems and provide feasible methods for improving efficiency in chemical applications.
文摘A hybrid rocket engine test bench experiment carried out the thrust 300 N,retaining nitrous gas as an oxidant,and 70 weight percent paraffin and 30 weight percent aluminum as fuel.To enhance the regression rate,new fuels such as paraffin-based fuel have been created,allowing for more compact engine designs with high thrust densities.As a result,the use of hybrid rocket engines in several domains,such as sounding rockets and small satellites for educational purposes and launch vehicle propulsion systems,has become possible.The solid fuel grain diameter is assumed to spread the characterization under different conditions.Estimate the rocket performance in the assumed condition and develop the test bench setup.In this paper,the data are composed of a 165 mm length of grain,external diameter is 79.6 mm and internal/port diameter is 8 mm.The injector plate used in this experiment is three injector holes with 120°.This injector is a showerhead that is simple in design and it is frequently used in hybrid rocket engines.Constraints such as the pressure in the combustion chamber being 50 bar and the SS304 nozzle,thrust were measured.Four separate test series were conducted.In the first test,one hole in the showerhead injector geometry was studied.In the 2nd,3rd,and 4th tests,injector plates with three injector holes were used.The test bench of a hybrid rocket engine has many components(oxidizer/pressure tank,combustion chamber with the pre-combustion,post-combustion chamber,conical shape nozzle,igniter,injector plate,etc.).
文摘With the advent of new technologies in space science,numerous missions and programs to launch satellites of various scales have received significant attention in the scientific community.However,there are a few complexities involved to encourage activities such as space tourism and exploration due to the technical constraints that the launch vehicle poses.To surmount these challenges,a novel hybrid rocket engine must be designed which allows us to tailor the characteristics during its endurance simulations.In the current work,we have investigated the propellant’s thermal and flow characteristics such as glass transition and melting temperature,specific impulse,characteristic velocity,regression rate,and thrust,respectively,without compromising the performance of likewise liquid propellant engine.In the current work,we investigated propellant characteristics for pure paraffin wax with oxidizers,such as liquid oxygen and nitrous oxide,and pure paraffin with additives of aluminum,magnesium,and oxidizers.It was observed that pure paraffin with liquid oxygen and additive aluminum(30%weight)resulted in the highest specific impulse among other combinations,whereas differential scanning calorimeter investigations reported a reduction in latent heat with the increase in weight%of paraffin and aluminum powder.It is also suggested that heat flow at 10%weight complies with the hybrid rocket engine.
文摘Recent development in space mission demands safer and more cost-effective space missions.Hybrid rocket engine technological advancements have prolonged a critical stage in their development and it is the better option for such space missions,as it has a lot of advantages over the solid rocket motor and liquid rocket engine.It is simple in design,has high thrust density,low weight,and is safer than a liquid rocket engine.It has restarted capability,safe,low explosion risk,and high specific impulse than a solid rocket motor.This paper shows the numerical analysis of a hybrid rocket engine.The paper highlights the initial boundary conditions in the analysis of a 300-N hybrid rocket engine.The process started with a chemical kinematic examination of engine-compatible fuels and oxidizers.This investigation provided the fundamental parameters required for the design and subsequent dimensioning of a hybrid rocket engine.It also produced a three-dimensional design model,performed numerical analysis using ANSYS software,and validated the findings using existing literature.Using the k-εturbulence model and transient solver on 8 mm port diameter for analyzing.The computational fluid dynamics model offered the qualities of a real hybrid rocket engine and it will be helpful to researchers and the scientific community in the future.
