In this paper,the gas and seed flow characters in the air-blowing seed metering device are investigated by using the coupled computational fluid dynamics and discrete element method(CFD-DEM)in three dimensions(3D).The...In this paper,the gas and seed flow characters in the air-blowing seed metering device are investigated by using the coupled computational fluid dynamics and discrete element method(CFD-DEM)in three dimensions(3D).The method of establishing boundary model based on the computer-aided design(CAD)drawing,has been used to build the boundary model of seed metering device.The 3D laser scanning technique and multi-element method are adopted to establish the particle model.Through a combined numerical and experimental effort,using 3D CFD-DEM software,which is based on the in-house codes,the mechanisms governing the gas and solid dynamic behaviors in the seed metering device have been studied.The gas velocity field and the effect of different rotational speeds and air pressures on the seeding performance and particle velocity have been studied,similar agreements between numerical and experimental results are gained.This reveals that the 3D CFD-DEM model established is able to predict the performance of the air-blowing seed metering device.It can be used to design and optimize the air-blowing seed metering device and other similar agriculture devices.展开更多
To design a Double-Pole Four-Throw (DP4T) RF switch, measurement of device parameters is required. In this DP4T RF switch CMOS is a unit cell, so with a thin oxide layer of thickness 628 ? which is measured optically....To design a Double-Pole Four-Throw (DP4T) RF switch, measurement of device parameters is required. In this DP4T RF switch CMOS is a unit cell, so with a thin oxide layer of thickness 628 ? which is measured optically. Some of the material parameters were found by the curve drawn between Capacitance versus Voltage (C-V) and Capacitance versus Frequency (C-F) with the application of Visual Engineering Environment Programming (VEE Pro). To perform the measurement processing at a distance, from the hazardous room, we use VEE Pro software. In this research, to acquire a fine result for RF MOSFET, we vary the voltage with minor increments and perform the measurements by vary the applying voltage from +5 V to –5 V and then back to +5 V again and then save this result in a data sheet with respect to temperature, voltage and frequency using this program. We have investigated the characteristics of RF MOSFET, which will be used for the wireless telecommunication systems.展开更多
The metering device is the central part of the seeder discharging granular fertilizers or seeds from the hopper to the colter passing through the tube.Depending on the metering device design,the batches of particles a...The metering device is the central part of the seeder discharging granular fertilizers or seeds from the hopper to the colter passing through the tube.Depending on the metering device design,the batches of particles are discharged or discharged evenly.This research analyzes existing metering devices,and a new pin-roller metering device is recommended to discharge evenly high doses of granular fertilizers and wheat seeds at low rotation speeds.The objective was to adapt the metering device to precision agriculture so that a little electric motor containing gearbox drives every metering device.Therefore,the pin-roller metering device parameters were investigated to apply high doses of granular fertilizers and wheat seeds evenly.The optimal pin positions were determined according to response surface methods(RSM)by simulating the granular fertilizers and wheat seeds'behavior on DEM.The coefficient of variation(CV)and the slip rate(SR)of the particles between the pins were chosen as indicators for evaluating the pin-roller.The shape of the pin was specified,and then the number of lines,the number of pins in a line,and the pin height were chosen to optimize.The analysis of the simulation results shows the optimal parameters:the number of pins in a line is four,and the number of lines is sixteen.The SR of granular fertilizers and wheat seeds were 8%and 2%,respectively.The pin-roller metering device is compared with the six-grooved and twelve-grooved metering devices.The comparison results show that the pin-roller metering device distributes twice more uniformly than other metering devices.The CV of the granular fertilizer distribution for six-grooved,twelve-grooved,and pin-roller metering devices was 111.13%,80.74%,and 37%,respectively.The CV of the wheat seed distribution for twelve-grooved and pin-roller metering devices was 96%,and 37%,respectively.As long as the particles interact with the tube,leaving the metering device,the effect of tube type and position is investigated.As a result,it was determined that the tube has minimal effect on the pin-roller metering device while positively impacting the six-grooved and twelve-grooved metering devices,improving the CV of the particle distribution into the soil.展开更多
This study aimed to optimize a three-row air-suction Brassica chinensis precision metering device to improve the low seeding performance.ANSYS 17.0 Software was used to analyze the effect of different numbers of sucti...This study aimed to optimize a three-row air-suction Brassica chinensis precision metering device to improve the low seeding performance.ANSYS 17.0 Software was used to analyze the effect of different numbers of suction holes and different suction hole structures on the airflow field.It was found that a suction hole number of 60 was beneficial to the flow field stability and a conical hole structure was beneficial to the adsorption of seeds.Box-Behnken design experiments were carried out with negative pressure,rotational speed,and hole diameter as the experimental factors.The optimal parameter combination was achieved when the negative pressure was 3.96 kPa,the rotational speed of the seeding plate was 1.49 rad/s and the hole diameter was 1.10 mm.The qualification rate of inner,middle,and outer rings were 87.580%,90.548%,and 90.117%,respectively,and the miss seeding rate of inner,middle,and outer rings were 10.915%,7.139%,and 5.920%,respectively.展开更多
基金The authors would like to express appreciation for the support of Australia Research Council(IH140100035)Nature Science Foundation of China(51675218)+1 种基金Doctor Starting Foundation of Jiangxi University of Science and Technology(JXXJBS17078)Science and Technology Project of the Education Department of Jiangxi Province(GJJ180426).
文摘In this paper,the gas and seed flow characters in the air-blowing seed metering device are investigated by using the coupled computational fluid dynamics and discrete element method(CFD-DEM)in three dimensions(3D).The method of establishing boundary model based on the computer-aided design(CAD)drawing,has been used to build the boundary model of seed metering device.The 3D laser scanning technique and multi-element method are adopted to establish the particle model.Through a combined numerical and experimental effort,using 3D CFD-DEM software,which is based on the in-house codes,the mechanisms governing the gas and solid dynamic behaviors in the seed metering device have been studied.The gas velocity field and the effect of different rotational speeds and air pressures on the seeding performance and particle velocity have been studied,similar agreements between numerical and experimental results are gained.This reveals that the 3D CFD-DEM model established is able to predict the performance of the air-blowing seed metering device.It can be used to design and optimize the air-blowing seed metering device and other similar agriculture devices.
文摘To design a Double-Pole Four-Throw (DP4T) RF switch, measurement of device parameters is required. In this DP4T RF switch CMOS is a unit cell, so with a thin oxide layer of thickness 628 ? which is measured optically. Some of the material parameters were found by the curve drawn between Capacitance versus Voltage (C-V) and Capacitance versus Frequency (C-F) with the application of Visual Engineering Environment Programming (VEE Pro). To perform the measurement processing at a distance, from the hazardous room, we use VEE Pro software. In this research, to acquire a fine result for RF MOSFET, we vary the voltage with minor increments and perform the measurements by vary the applying voltage from +5 V to –5 V and then back to +5 V again and then save this result in a data sheet with respect to temperature, voltage and frequency using this program. We have investigated the characteristics of RF MOSFET, which will be used for the wireless telecommunication systems.
基金the financial support provided by the National Key Research and Development Program of China(Grant No.2018YFD0701102).
文摘The metering device is the central part of the seeder discharging granular fertilizers or seeds from the hopper to the colter passing through the tube.Depending on the metering device design,the batches of particles are discharged or discharged evenly.This research analyzes existing metering devices,and a new pin-roller metering device is recommended to discharge evenly high doses of granular fertilizers and wheat seeds at low rotation speeds.The objective was to adapt the metering device to precision agriculture so that a little electric motor containing gearbox drives every metering device.Therefore,the pin-roller metering device parameters were investigated to apply high doses of granular fertilizers and wheat seeds evenly.The optimal pin positions were determined according to response surface methods(RSM)by simulating the granular fertilizers and wheat seeds'behavior on DEM.The coefficient of variation(CV)and the slip rate(SR)of the particles between the pins were chosen as indicators for evaluating the pin-roller.The shape of the pin was specified,and then the number of lines,the number of pins in a line,and the pin height were chosen to optimize.The analysis of the simulation results shows the optimal parameters:the number of pins in a line is four,and the number of lines is sixteen.The SR of granular fertilizers and wheat seeds were 8%and 2%,respectively.The pin-roller metering device is compared with the six-grooved and twelve-grooved metering devices.The comparison results show that the pin-roller metering device distributes twice more uniformly than other metering devices.The CV of the granular fertilizer distribution for six-grooved,twelve-grooved,and pin-roller metering devices was 111.13%,80.74%,and 37%,respectively.The CV of the wheat seed distribution for twelve-grooved and pin-roller metering devices was 96%,and 37%,respectively.As long as the particles interact with the tube,leaving the metering device,the effect of tube type and position is investigated.As a result,it was determined that the tube has minimal effect on the pin-roller metering device while positively impacting the six-grooved and twelve-grooved metering devices,improving the CV of the particle distribution into the soil.
基金This research was financailly supported by the National Key R&D Program of China“Vegetable Intelligent Fine Production Technology and Equipment R&D”(Grant No.2017YFD0701302).
文摘This study aimed to optimize a three-row air-suction Brassica chinensis precision metering device to improve the low seeding performance.ANSYS 17.0 Software was used to analyze the effect of different numbers of suction holes and different suction hole structures on the airflow field.It was found that a suction hole number of 60 was beneficial to the flow field stability and a conical hole structure was beneficial to the adsorption of seeds.Box-Behnken design experiments were carried out with negative pressure,rotational speed,and hole diameter as the experimental factors.The optimal parameter combination was achieved when the negative pressure was 3.96 kPa,the rotational speed of the seeding plate was 1.49 rad/s and the hole diameter was 1.10 mm.The qualification rate of inner,middle,and outer rings were 87.580%,90.548%,and 90.117%,respectively,and the miss seeding rate of inner,middle,and outer rings were 10.915%,7.139%,and 5.920%,respectively.
