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Detection and assessment of nitrogen effect on cold tolerance for tea by hyperspectral reflectance with PLSR, PCR, and LM models

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Information Processing in Agriculture 2021年第1期8卷 96-104页

作者： eric amoah asante Zhe Du Yongzong Lu Yongguang Hu School of Agricultural Equipment Engineering Institute of Agricultural EngineeringJiangsu UniversityZhenjiangJiangsu 212013China Department of Mechanical Engineering Faculty of EngineeringKoforidua Technical UniversityKoforiduaGhana

Knowledge of nutrients effect on freezing tolerance is vital for protecting tea plants against cold injury(CI).Freezing injury treatments on tea leaves with different low temperature and nitrogen(N)concentration was evaluated by hyperspectral imaging based on the reflectance as potential analytical ***,quantitative evaluation of the CI was improved by comparing analyzed results using partial least squares regression(PLSR),principle component regression(PCR)and linear model(LM)*** of the CI was obtained by hyperspectral imaging system in the band between 871 and 1766 *** results showed that average reflectance increases with the rise of N concentration.A substantial portion of the leaf from the plant with 100%N dosage had the darkest image and resulted in the highest reflectance because the N weakened the negative effect of freezing *** of the five spectral domains tested,the best predictive accuracy for the CI of the tea leaf was achieved by PCR(R^(2)=0.9971,RMSE=0.0609)in 1410–1766 nm wavelength,followed by LM(R^(2)=0.9999,RMSE=0.0805)in 871–1000 *** whole interval had the worse prediction accuracy which could be caused by large variations in the data for a specific treatment and high absorption peak occurring around 1450 nm in the reflectance *** averages,R^(2) and RMSE for all the three statistical models showed that the worse prediction accuracy occurred in 1410–1766 nm,followed by the whole interval 871–1766 *** prediction accuracy was low which could be due to the strong water absorption peaks that appeared in both range of *** models without absorption bands had improved correlation coefficient and reduced RMSE values between the measured and the predicted CI(R^(2)=0.9676;RMSE=0.3067)compared to the model developed with the reflectance values in the entire waveband(R^(2)=0.9504;RMSE=0.6629).The reflectance values where absorption bands occurred had detrimental effect on the model performance,which

关键词： Cold injury Hyperspectral imaging Reflectance Principal component

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Review of air disturbance technology for plant frost protection

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International Journal of Agricultural and Biological Engineering 2018年第3期11卷 21-28页

作者： Yongguang Hu eric amoah asante Yongzong Lu Ashraf Mahmood Noman Ali Buttar Shouqi Yuan School of Agricultural Equipment Engineering Jiangsu UniversityZhenjiang 212013China Faculty of Engineering Koforidua Technical UniversityKoforiduaGhana Research Center of Fluid Machinery Engineering and Technology Jiangsu UniversityZhenjiang 212013China

Confronted with severe frost damage to plants,methods,technologies and equipment have been developed and applied during the past *** paper presents a comprehensive review on the most effective and active technology to protect plants from radiation frost based on air disturbance *** working principle of the technology was elaborated with frost protection mechanism,structures and applicability of three types of working patterns:conventional wind machines,selective inverted sink and portable vertical *** an automatic mechanized technology,control strategy,applicable occasion and proper parameters are introduced for each type of working *** operation of the technology and equipment depends on plant critical temperature,prevailing climatic conditions,thermal inversions strength,as well as *** frost protection performance and effectiveness of conventional horizontal wind machines,selective inverted sinks and helicopters are discussed and compared from the cost-effectiveness and application aspects,and the feasibility of selective inverted sinks is still ***,conventional wind machines are the best choice for plant frost protection and consequently are widely used in temperate and subtropical areas throughout the *** frost protection application with helicopters is not easy to use during the frost nights with high *** paper also provides researchers with some perspectives on improving air disturbance technology and its equipment,and some practice recommendations for growers.

关键词： thermal inversion plant frost protection air disturbance technology wind machine cost-effectiveness control technology

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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

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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

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