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Tree-Temperature Monitoring for frost protection of Orchards in Semi-Arid Regions Using Sprinkler Irrigation

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Agricultural Sciences in China 2009年第1期8卷 98-107页

作者： Ali Asghar Ghaemi Mohammad Rafie Rafiee Ali Reza Sepaskhah Irrigation Department College of AgricultureShiraz University

Automated over-tree sprinkler irrigation systems were developed and tested in two orchards located in two separate locations in southern Iran （a 0.17 ha peach orchard and a 0.24 ha orange orchard） to protect peach blossoms and orange trees leaves and fruits from low temperature damage. The experiment used a system that monitored the trees and air temperatures using two thermistors. The water application rate by the irrigation system was determined by an energy balance as implemented by the software frostPRO, In the peach orchard, the system was tested during three frost events during the spring of 2003 and three other events during the spring of 2004. The system successfully kept peach flowers above the critical temperature, i.e., -4.0℃ in spring 2004 （control block -4.12℃, and sprinkled block ＋0.5℃） during all events. Similar results were obtained in the orange orchard during three frost events in the winter of 2004, during which the tree temperatures were at least 2.5℃ above the critical temperature. Results from field tests show that the system can effectively protect the peach blossoms from damage. Determination done after the frost events showed a 12% blossom kill in the sprinkled blocks while in the unsprinkled control block a 41.5% blossom kill. Calculations indicated that when using variable application rates, the amount of water used can be reduced by 54.3%. Spatial distribution of minimum temperatures during the three frosts was also studied in Jahrom, Iran. Results showed a significant temperature control in the experimental block, especially in the central part of the orchard, but the block margins （about 3.6% of the total area） were at the risk of low temperature due to the wind drift effects.

关键词： automated sprinkler irrigation frostPORO frost protection peach orchard orange orchard

Optimal flight parameters of unmanned helicopter for tea plantation frost protection

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International Journal of Agricultural and Biological Engineering 2015年第5期8卷 50-57页

作者： Hu Yongguang Liu Shengzhong Wu Wenye Wang Jizhang Shen Jianwen School of Agricultural Equipment Engineering Jiangsu UniversityZhenjiang 212013China Electronic Application Laboratory of Wuxi Hanhe Unmanned Helicopters Wuxi 214135China

To determine proper flight parameters of an unmanned helicopter for tea plantation frost protection,field experiments were conducted to study the impact of flight height,speed and interval on airflow disturbance and temperature rise around tea canopies based on the analysis and simulation of frost protection with a certain *** relationship between temperature rise after flight and the above flight parameters was established through a regression orthogonal experiment,based on which the optimal combination of flight parameters was obtained through the single-factor golden section *** results showed that wind speed around tea canopies decreased with the increase of flight height when flight speed was *** was a multivariate linear relationship between temperature rise and flight parameters,and the sequence of flight parameters’influence on frost protection effect was flight interval,flight height,flight *** optimal combination of flight parameters were flight height of 4.0 m,flight speed of 6.0 m/s and flight interval of 20 *** the flight with the above parameters air temperature around tea canopies increased 1.6℃ when background thermal inversion strength was 3.8℃.

关键词： thermal inversion frost protection unmanned helicopter flight parameters orthogonal experiment single-factor golden section method tea plants

Optimal design of wind machine impeller for frost protection based on CFD and its field test on airflow disturbance

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International Journal of Agricultural and Biological Engineering 2015年第5期8卷 43-49,I0002页

作者： Wu Wenye Hu Yongguang Yang Shuo Mao Kangqian Zhu Xiaoyong Li Pingping School of Agricultural Equipment Engineering Jiangsu UniversityZhenjiang 212013China College of Biology and the Environment Nanjing Forestry UniversityNanjing 210037China

Wind machines have been increasingly applied to prevent frost damage through airflow disturbance in tea fields and *** impeller is the most important component of the ***,there are few studies on customized impeller design or airflow disturbance *** objective of this study was to design a new impeller for frost protection wind machines based on reverse engineering and CFD *** characteristic parameters of an impeller include blade cross-section shape,installation angle,sweep angle,hub ratio and blade *** optimal combination of the above parameters was obtained through the simulation of the impeller’s aerodynamic *** tests were conducted in a tea field to evaluate airflow disturbance performance of the designed *** result shows that at a certain rotation speed and rotation diameter,the optimal combination of impeller parameters was:single arc cross-section ofϕ2400 mm,installation angle of 15°,sweep angle of 87°,hub ratio of 0.3 and blade number of 4,of which the impeller could achieve the highest usage of 0.56,the least consumed power of 1.363 kW and more uniform distribution of surface pressure on the windward *** with other commercial frost protection wind machines,the maximum airflow velocity of the developed impeller was higher at 12 m in front of *** probability of airflow velocity above 3.0 m/s within 30 min was the highest(71.7%),indicating its improvement of airflow *** swing the new impeller could cover an effective area of 300 m2,which was similar to that of the commercial ones.

关键词： frost protection wind machine impeller CFD reverse engineering airflow disturbance tea orchard

Sprinkler irrigation system for tea frost protection and the application effect

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International Journal of Agricultural and Biological Engineering 2016年第5期9卷 17-23页

作者： Hu Yongguang Zhao Chen Liu Pengfei Asante Eric Amoah Li Pingping Key Laboratory of Modern Agricultural Equipment and Technology Jiangsu UniversityZhenjiang 212013China College of Biology and the Environment Nanjing Forestry UniversityNanjing 210037China

A sprinkler irrigation system was designed and applied for a tea field to achieve frost protection through latent heat release when water turning into *** protection effects during night were tested at different irrigation application rates by monitoring air temperature around tea canopy(Tc).Temperature sensors were arranged at different distances from the *** preliminary results showed that,when the sprinkler system worked continuously at the application rate of 2-4 mm/h before sunrise,tea canopy was covered with ice and Tc remained around 0℃,preventing tea plants from frost *** no more temperature rise was obviously observed at the application rates above 4 mm/h,which means less cost *** system was stopped after sunrise when background air temperature rose back to 0℃and Tc increased by 2.2℃in one hour,while Tc of non-irrigated area increased by 4.8℃,which might cause thawing injuries to tea *** leaf surface temperature was lower than Tc,and the difference between the leaf surface temperature and Tc decreased with the increase of application ***,the sprinkler irrigation system could achieve tea frost protection,and the recommended application rate was 2-4 mm/h for better protection *** system should keep running throughout frost night till half an hour after *** start and stop of the sprinkler irrigation system should be controlled based on Tc.

关键词： sprinkler irrigation frost protection Camellia Sinensis L application rate temperature rise frost damage

Control system of a performance test-bed for frost protection wind machines

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International Journal of Agricultural and Biological Engineering 2016年第6期9卷 36-43页

作者： Hu Yongguang Liu Ping Asante Eric Amoah Wu Wenye Li Pingping Key Laboratory of Modern Agricultural Equipment and Technology Jiangsu UniversityZhenjiang 212013China College of Biology and the Environment Nanjing Forestry UniversityNanjing 210037China

To test the performance and optimize operational parameters of various frost protection wind machines,a control system of performance test-bed was designed and developed based on Programmable Logic Controller(PLC)and touch *** system realized automatic control of operational parameters including hydraulic platform height,impeller rotation speed,depression angle,rotation range and *** case study results shows that the control accuracy of all the parameters was achieved with the average errors of 2.11 cm for height,9.5 r/min for impeller rotation speed,0.83°for pan-tilt rotation range and 0.061 min for rotation *** the control of the test-bed,the performances of various wind machines,such as the distribution of airflow and temperature,and frost protection effect,could be tested under various working conditions,which provide experiment supports for developing wind machines adapted to different conditions with higher frost protection effect.

关键词： frost protection wind machines performance test-bed design control PLC

Tea leaf’s microstructure and ultrastructure response to low temperature in indicating critical damage temperature

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Information Processing in Agriculture 2019年第2期6卷 247-254页

作者： Yongzong Lu Yongguang Hu Richard LSnyder Eric RKent Key Laboratory of Modern Agricultural Equipment and Technology Ministry of Education Jiangsu ProvinceJiangsu UniversityZhenjiangJiangsu 212013China Department of Land Air and Water ResourcesUniversity of CaliforniaDavisDavis 95616USA Department of Plant Sciences University of CaliforniaDavisDavis 95616USA

To find out the critical damage temperature of tea leaf,a new method of subzero treatment was provided by fitting the air temperature data from six heavy frost ***,the study explored the characteristics of Fuding Dabai tea plant response to low temperature stress of 2,0,2,4,8,10 and15C by observing the microstructure and ultrastructure changes of the *** samples were collected in an ambient temperature of 8.6C which served as *** electron microscopy(SEM)and transmission electron microscopy(TEM)were used to observe the microstructure and ultrastructure of stomata and *** observation results indicated that stomata of tea leaves have an obvious low temperature stress when the temperature was lower than2*** extent of opening of the stomata increased and enhanced guard cell protection of tea leaves against cold ***,dehydration,shrinkage and deformation of cells occurred as the temperature decreased from2C to15*** observations showed that the cell nucleus,cell walls,chloroplasts and mitochondria all had normal structure at a temperature of 8.6C where the membrane and granum lamella were clearly *** the temperature decreased to2C,the membrane system of tea leaf was the first to be damaged and the cell walls became ***,the leaf microstructure and ultrastructure showed obvious changes at2C,which might define the critical damage temperature for freeze damage of Fuding Dabai *** strategy based this critical damage temperature is useful for wind machine frost protection in tea fields within the Yangtze River region.

关键词： frost damage Freeze injury Chill injury frost protection