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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

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

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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融资约束与创新 ——来自加纳企业的证据

融资约束与创新 ——来自加纳企业的证据

作者： eric asante 厦门大学

学位级别：硕士

本文研究了融资约束对加纳企业创新的影响。本文使用2013年世界银行企业调查数据中的关于融资约束和创新的测度指标,考虑了企业创新决策的的潜在内生性问题利用双变量Probit模型来进行估计。研究发现融资约束显着降低了公司的创新决策... 详细信息

本文研究了融资约束对加纳企业创新的影响。本文使用2013年世界银行企业调查数据中的关于融资约束和创新的测度指标,考虑了企业创新决策的的潜在内生性问题利用双变量Probit模型来进行估计。研究发现融资约束显着降低了公司的创新决策。然而,这种负面影响因行业和公司规模而异。在制造业行业,融资约束的负面影响似乎比零售和其他服务(非零售)行业更为明显,而就企业规模而言,小企业受到融资约束的负面影响更大。

关键词：融资约束创新加纳

Extrauterine Pregnancy: A Nine-Year Review of Incidence, Seasonality and Management at a Tertiary Hospital in Southern Ghana

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Open Journal of Obstetrics and Gynecology 2020年第2期10卷 264-274页

作者： Evans Kofi Agbeno Anthony Amanfo Ofori Joseph Osarfo Doughan Samuel Joseph amoah Adu Sebastien Ken-amoah Wisdom Klutse Azanu Department of Obstetrics and Gynaecology School of Medical Sciences University of Cape Coast Cape Coast Ghana Department of Obstetrics and Gynaecology Cape Coast Teaching Hospital Cape Coast Ghana Ghana Health Service Asante Mampong Municipal Hospital Asante Mampong Ghana Department of Obstetrics and Gynaecology School of Medicine University of Health and Allied Sciences Ho Ghana

Introduction: Most cases of extrauterine pregnancies present in the ruptured state in low-resource settings and patients with haemodynamic instability risk mortality without swift intervention. An idea of when ectopic gestations are likely to present may be useful for logistic planning and facility readiness for case management. The study sought to assess the incidence of extrauterine gestation, mode of management and any link with seasonal and/or sociocultural events within the Cape Coast metropolis of Ghana over a 9-year review period.?Methods: A retrospective review of all cases of extrauterine pregnancies managed at the Cape Coast Teaching Hospital (CCTH) from January 2010 to December 2018 was conducted. Data on patient age, parity, month of presentation, site and laterality of ectopic gestation, number of abortions and deliveries were retrieved from hospital records and analysed. Yearly and monthly aggregated incidence of extrauterine pregnancies were computed.?Result: A total of 480 ectopic pregnancies out of 26,850 total pregnancies were seen over the period, giving an overall occurence of 17.9/1000 pregnancies and almost all were managed surgically. Half of all the cases occurred in the 20?-?29 years age group while the extremes of age recorded the lowest. An average of about 53 cases per year was recorded for the period under review. The peak months of occurrence were October and November. About 83% were ruptured with the ampulla region being the commonest site. Conclusion: The data suggests increased ectopic gestation occurrence in the Cape Coast metropolis about two months after the major traditional festivals and this may have implications for instituting mitigating measures, logistic management and facility preparedness for case management.

关键词： Extrauterine Pregnancy Seasonality Incidence Ghana Management Options