<RECORD 1>
Accession number:20190206357030
Title:Influence of spectral transformation methods on nutrient content inversion accuracy by hyperspectral remote sensing in black soil
Authors:Zhang, Donghui (1); Zhao, Yingjun (1); Qin, Kai (1); Zhao, Ningbo (1); Yang, Yuechao (1)
Author affiliation:(1) National Key Laboratory of Remote Sensing Information and Imagery Analyzing Technology, Beijing Research Institute of Uranium Geology, Beijing; 100029, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:141-147
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In order to improve the precision and stability of the soil nutrient content inversion model in black soil area, taking Jiansanjiang area in Heilongjiang province as the study area, and the airborne hyperspectral imaging system CASI-1500 (380-1 050 nm) as the analysis data, the influence of different spectral transformation methods on the accuracy was researched. 60 samples were evenly sampled, and the contents of organic matter, total nitrogen, total phosphorus and total potassium were obtained through laboratory tests. The content of organic matter was determined by potassium dichromate capacity external heating method. The content of total nitrogen, total phosphorus and total potassium was determined by Kjeldahl method, NaOH alkali antimony colorimetric method and potassium flame atomic absorption spectrophotometry. 60 black soil samples were sorted according to nutrient content, and the spectral transformation in the visible near red range was analyzed. The change rule of organic matter is that the reflectance decreases with the increase of content. The change rule of nitrogen is similar to the spectral curve of organic matter. With the increase of nitrogen content, the reflectance decreases. The transformation of phosphorus and potassium in the visible near red spectrum is not significant. The nutrient correlation coefficients of 60 samples at different sampling points were calculated by spectral reflectance. The results show that the correlation coefficient of each band is the highest, the mean value is 0.39, the correlation coefficients of nitrogen and phosphorus are close to 0.28 and 0.30, and the correlation coefficient of potassium is the lowest, which is 0.05. The first 5 bands with high correlation coefficient are selected as modeling bands, that of organic matter is 933.6, 914.5, 905, 866.8 and 943.1 nm, and that of nitrogen is 933.6, 866.8, 876.3, 847.7 and 914.5 nm. The content of organic matter and support vector machine were used to model nitrogen, phosphorus and potassium contents. The extraction accuracies of 5 spectral transformations which are resampling (RE), logarithmic reciprocal (LR), first order derivative (FD), continuum removal (CR) and multivariate scatter correction (MSC) transformation are compared. The most accurate methods for the spectral transformation of organic matter, nitrogen, phosphorus and potassium are MSC, MSC, LR and RE, respectively. Five spectral transformation methods are used to calculate the R<sup>2</sup> of each model, and the order of modeling accuracy for soil organic matter prediction is MSC (0.922) > RE (0.529) > LR (0.432) > CR (0.414) > FD (0.018). The modeling accuracy of multiple scattering correction transformation is significantly higher than that of the other four methods. The order of prediction accuracy or total phosphorus is MSC (0.872) > CR (0.387) > RE (0.256) > LR (0.029) > FD (0.012), and the prediction accuracy of the multivariate scattering correction transformation is also the highest. The highest prediction accuracies of total phosphorus and total potassium are LR (0.621) and RE (0.423). In turn, the MSC, MSC, LR and RE spectral transformation methods with high coefficient of determination are applied to the combined operation of the characteristics of organic matter, nitrogen, phosphorus and potassium, and the spatial distribution of nutrient content in black soil is obtained. The results show that the spectral transformation methods of MSC, MSC, LR and RE are applied to calculate soil organic matter, nitrogen, phosphorus and potassium, respectively, the spatial distribution accuracy of nutrient content in black soil is the highest, and the determination coefficients of predicted samples are 0.748, 0.673, 0.631 and 0.420, respectively.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:33
Main heading:Soil surveys
Controlled terms:Biogeochemistry - Biological materials - Chromates - Finite difference method - Forecasting - Hyperspectral imaging - Metadata - Models - Neural networks - Nitrogen - Nutrients - Organic compounds - Phosphorus - Potassium compounds - Reflection - Remote sensing - Sodium hydroxide - Soils - Spatial distribution - Spectroscopy - Support vector machines
Uncontrolled terms:Airborne hyperspectral imaging - Coefficient of determination - Determination coefficients - Flame atomic absorption spectrophotometry - Hyperspectral remote sensing - Nitrogen and phosphorus - Spectral transformation methods - Spectral transformations
Classification code:461.2 Biological Materials and Tissue Engineering - 481.2 Geochemistry - 483.1 Soils and Soil Mechanics - 723 Computer Software, Data Handling and Applications - 804 Chemical Products Generally - 921 Mathematics - 921.6 Numerical Methods
Numerical data indexing:Size 3.80e-07m to 1.05e-06m, Size 8.48e-07m, Size 8.67e-07m, Size 9.15e-07m, Size 9.43e-07m
DOI:10.11975/j.issn.1002-6819.2018.20.018
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 2>
Accession number:20190206357025
Title:Migration characteristics and its differences of reclaimed water salinity in different subtropical soils
Authors:Hu, Chuanwang (1); Wang, Hui (1); Wu, Yun (1); Lu, Jiayu (1); Li, Yuyuan (2)
Author affiliation:(1) College of Engineering, Hunan Agricultural University, Changsha; 410128, China; (2) Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha; 410125, China
Corresponding author:Wang, Hui(wanghuisb@126.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:99-107
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:To evaluate reasonably the effect of reclaimed water irrigation salt in the soil environment, varying salinity in the effluent of salty solution leaching subtropical soil and the effect on soil chemical properties were analyzed. In this paper, five subtropical soils: clay fluvo aquic soil, sandy fluvo aquic soil, red soil, purple soil and paddy soil were selected as the research object. Use the constant head infiltration method to observe the differences in electrical conductivity (EC) and pH of effluent after leaching of soils with different concentrations of sodium salt solution (EC of solutions was 1.96, 4.77, 9.08, 17.25 and 25.06 dS/m, respectively). The results showed that the high concentration salt solution had weaker penetrating ability in red soil, purple soil and clay fluvo aquic soil with higher clay content than paddy soil and sandy fluvo aquic soil with low clay content. The same treatment achieved the same degree of penetration, and acidic soil (red soil, purple soil, paddy soil) can withstand more low quality water. In addition, the migration rate of salinity in the soil was mainly determined by the physicochemical properties of the soil. Soil clay content and exchangeable aluminum content significantly slowed the migration of salinity in the soil, while the soil silt content, EC, pH value and exchangeable calcium and magnesium content promoted the migration of salt in the soil. Salt can easily flow out through alkaline soil (clay fluvo aquic soil and sandy fluvo aquic soil). The maximum change rate of relative EC from the alkaline soil effluent was 36% higher than that of the acidic soil. The concentration of inflow salt had an obvious influence on the relative EC change rate and the penetration process of the red soil effluents, and it mainly affected the relative EC change rate for the purple soil, the clay fluvo aquic soil and the sandy fluvo aquic soil, which mainly affected the lag degree of the penetration process for paddy soil. The Boltzmann fitting showed the infiltration water salt concentration and soil physical and chemical properties had a significant impact on the model parameters (P<0.05). Moreover, the degree of soil chemical properties affected by the salt concentration in the infiltration solution was not only related to its own chemical properties, but also had a very significant relationship with the content of powder particles and clay in the soil texture (P<0.01). The concentration of salt solution had no significant (P > 0.05) effect on the pH value of alkaline soil, and had a greater effect on the pH value of acidic soil. The pH of the effluent decreased by 1.6-2.6 units, of which red soil had the greatest change in pH value, followed by purple soil. The influence of infiltration solution with EC higher than 4.77 dS/m on the stable pH value of soil effluent did not increase substantially. Therefore, when irrigating with low quality water, the salt concentration in the water should be sufficiently limited according to the physicochemical properties of the soil. The research results can serve as reference for reclaimed water irrigation and calculation of water and salt transport in subtropical regions.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:32
Main heading:Infiltration
Controlled terms:Alkalinity - Chemical analysis - Effluents - Electric arc welding - Irrigation - Leaching - pH - Reclamation - Soils - Tropics
Uncontrolled terms:Break through curve - Calcium and magnesiums - Electrical conductivity - Physicochemical property - Salt solution - Soil chemical property - Soil physical and chemical properties - Water and salt transports
Classification code:443 Meteorology - 452.3 Industrial Wastes - 483.1 Soils and Soil Mechanics - 538.2.1 Welding Processes - 801.1 Chemistry, General - 802.3 Chemical Operations - 821.3 Agricultural Methods
Numerical data indexing:Percentage 3.60e+01%
DOI:10.11975/j.issn.1002-6819.2018.20.013
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 3>
Accession number:20190206357017
Title:Effect of spray adjuvant types and concentration on nozzle atomization
Authors:Zhang, Ruirui (1, 2, 3); Zhang, Zhen (2, 3, 4); Xu, Gang (1, 2, 3); Chen, Liping (1, 2, 3); Hewitt, Andrew J (5)
Author affiliation:(1) Beijing Research Center of Intelligent Equipment for Agriculture, Beijing; 100097, China; (2) National Research Center of Intelligent Equipment for Agriculture, Beijing; 100097, China; (3) National Center for International Research on Agricultural Aerial Application Technology, Beijing; 100097, China; (4) College of Information Science and Engineering, Shandong Agricultural University, Tai'an; 271018, China; (5) Centre for Pesticide Application and Safety, University of Queensland, QLD; 4072, Australia
Corresponding author:Chen, Liping(chenlp@nercita.org.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:36-43
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In order to achieve the purpose of reducing pesticide application while increasing efficacy, adjuvant has become an essential part of pesticide application process. The application amount of adjuvant directly affects the pesticide utilization. In order to study the effects of adjuvant on volume median diameter (VMD) of spray droplet and relative span of droplet size, a laser diffraction system was used to investigate the spray droplet characteristics of different adjuvants with different hydraulic nozzles. Three different adjuvants were tested with 2 types of nozzles, IDK120-025 and LU120-015, under laboratory conditions. The 3 adjuvants used in the experiment were Italy, Jijian and Urea. Italy and Jijian are standard adjuvants. Urea is a kind of chemical nitrogen fertilizer, and when it is dissolved in water the liquid becomes cloudy. Generally it is applied to aerial spraying solution to increase droplet settlement. As Urea does not belong to the standard adjuvants, its effect on the atomization of the liquid is not yet clear, and solving this problem is also one of the experimental purposes of this experiment. Italy and Urea are powdery and Jijian is liquid form. IDK nozzle and LU nozzle are widely used in the spraying, and the nozzle size and spray angle are the same, but the spay chamber atomization structure is different. The internal structure design of the IDK nozzle utilizes the Venturi principle to mix the spray liquid with the air inside the nozzle to make the ejected droplets become small bubbles. Studies have shown that changes in the physical and chemical properties of the spray liquid system play a decisive role in the correlation between the liquid film length and droplet size. Because the difference in physical and chemical properties of tap water and distilled water may affect the particle size of droplets, the experiment also uses tap water and distilled water as the experimental control groups. The results show that the 3 adjuvants have a more significant effect on IDK120-025. However, the spray mist droplet uniformity of LU120-015 nozzle is better than IDK120-025 nozzle. When the concentration ratio of Jijian solution is 1:3000, the VMD of droplets sprayed by IDK nozzle can be increased by 20.43% compared to water at a pressure of 0.4 MPa, and the relative span of droplet size can be reduced by 1.74%. When the concentration ratio of Italy solution is 1:2000, the VMD of droplets sprayed by IDK nozzle can be increased by 11.10% compared to water at a pressure of 0.4 MPa, and the relative span of droplet size can be reduced by 8.86%. When the concentration ratio of Italy solution is 1:3000, the VMD of droplets sprayed by LU nozzle can be reduced by 5.99% compared to water at a pressure of 0.2 MPa, and the relative span of droplets size can be increased by 1.56%. When the concentration ratio of Urea solution is 1:2 000, the VMD of droplets sprayed by IDK nozzle can be increased by 16.92% compared to water at a pressure of 0.4 MPa, and the relative span of droplet size can be reduced by 6.92%. According to the ASABE S572.1 standard to evaluate the result of the experiment, the spray quality of IDK nozzle is focused on medium and coarse grades, the VMD of droplets is large and the difficulty of retention on wet leave surface is moderate, and the drift potential is at medium level. The spray quality of LU nozzle is focused on fine grade, the VMD of droplets is small and the retention ability on wet leave surface is good, but the drift potential is high. This experiment can provide foundation for the selection of adjuvants and nozzles in field pesticide application, and provide the data basis for further research on new nozzles and adjuvants.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:31
Main heading:Spray nozzles
Controlled terms:Antennas - Atomization - Chemical properties - Drops - Liquid films - Metabolism - Nitrogen fertilizers - Nozzle design - Nozzles - Particle size - Pesticides - Quality control - Spraying - Urea
Uncontrolled terms:Adjuvant - Experimental control - Internal structure designs - Laboratory conditions - Nozzle atomizations - Pesticide applications - Physical and chemical properties - Spray droplet sizes
Classification code:631.1 Fluid Flow, General - 801 Chemistry - 802.3 Chemical Operations - 803 Chemical Agents and Basic Industrial Chemicals - 804 Chemical Products Generally - 804.1 Organic Compounds - 913.3 Quality Assurance and Control
Numerical data indexing:Percentage 1.11e+01%, Percentage 1.56e+00%, Percentage 1.69e+01%, Percentage 1.74e+00%, Percentage 2.04e+01%, Percentage 5.99e+00%, Percentage 6.92e+00%, Percentage 8.86e+00%, Pressure 2.00e+05Pa, Pressure 4.00e+05Pa
DOI:10.11975/j.issn.1002-6819.2018.20.005
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 4>
Accession number:20190206357033
Title:Experiment on durability of recycled concrete under coupling multi-factors of load and corrosion freeze-thaw
Authors:Lei, Bin (1); Li, Zhaohang (1); Zou, Jun (1); Xiong, Jingang (1); Ding, Chengping (1)
Author affiliation:(1) School of Building Engineering and Architecture, Nanchang University, Nanchang; 330031, China
Corresponding author:Xiong, Jingang(xiongjingang@ncu.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:169-174
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Recycled aggregate concrete has obtained worldwide attention as an important part of sustainability. In the aspect of durability of recycled concrete under coupling multi-factors, a number of devices were designed and installed to investigate the durability of recycled concrete. In previous studies, the concrete specimen was tightened by the screws to apply a prestress with the jack, and then specimen was put in the devices for the durability test, which was difficult to operate and prone to stress loss. In this paper, in order to better research the durability of concrete under coupling multi-factors, we designed a coupling mechanism of alternated with loading and freeze-thaw cycles in salt-solution to replace the traditional mold loading to accurately simulate the simultaneous interaction of freezing thawing, corrosion and load. The coupling protocol was designed with repetitive load and 25 time's freeze-thaw cycles alternately 2 times in the salt-solution, in which the maximum stress level (the applied stress to 28 days compressive strength) of repetitive load is 0, 40%, 70%. The specific operation was that specimens were loaded repetitively for the first time, then they were freeze-thawed in the salt-solution for 25 time's cycles, after that, they were repetitively loaded again, and freeze-thawed in the salt-solution for another 25 time's cycles. The experiment on compressive strength and microhardness of recycled concrete and natural concrete under coupling action was carried out. In the macroscopic test, compressive strength loss of each specimen was measured under the above mentioned coupling protocols. At the same time, the microhardness across the ITZs between the coarse aggregate and the cement matrix was measured before and after 50 freeze-thawing cycles for the control specimens. The macro test results showed that the stress level of the coupling action increased from 40% to 70%, the compressive strength loss of both recycled concrete and natural concrete increased from 1.8% and 71.3% to 27.2% and 100% respectively. It is implied that the durability of recycled concrete under coupling action is better than that of natural concrete, and the loading mechanism with high stress level will accelerate the deterioration of both recycled concrete and natural concrete. The micro test results showed that the microhardness values gradually increased with the increases of distance from the interface of natural aggregate and cement paste, the microhardness losses were 8.1% and 23.8% of the interface of both recycled aggregate and natural aggregate before and after the coupling action respectively. It can be seen that the interface transition zone was the weakest part of the concrete, and the decreasing rate of microhardness of the interface transition zone in natural aggregate specimens was faster than that of recycled aggregate after 50 time's freeze-thaw cycles in salt-solution. The environmental scanning electron microscope (ESEM) test results indicated that the bond strength and plastic deformation ability of interface of natural aggregate are better than that of recycled aggregate before freeze-thaw cycles, while the ability to resist freeze-thaw at the interface transition zone of recycled aggregate was better than natural aggregate after freeze-thaw cycles. The related results can provide an insight into the long-term performance of recycled concrete subjected to harsh environmental conditions and thus to promote practical application of recycled aggregate concrete in the future.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:34
Main heading:Durability
Controlled terms:Aggregates - Cements - Compressive strength - Concrete testing - Concretes - Corrosion - Deterioration - Freezing - Loading - Microhardness - Recycling - Scanning electron microscopy - Stress analysis - Stresses - Sustainable development - Thawing
Uncontrolled terms:Environmental conditions - Environmental scanning electron microscopes - Freeze-thaw - Interface transition zones - Multi factors - Plastic deformation abilities - Recycled aggregate concrete - Recycled concretes
Classification code:406 Highway Engineering - 412 Concrete - 412.1 Cement - 452.3 Industrial Wastes - 691.2 Materials Handling Methods - 951 Materials Science
Numerical data indexing:Age 7.67e-02yr, Percentage 1.00e+02%, Percentage 1.80e+00%, Percentage 2.38e+01%, Percentage 4.00e+01%, Percentage 4.00e+01% to 7.00e+01%, Percentage 7.00e+01%, Percentage 7.13e+01% to 2.72e+01%, Percentage 8.10e+00%
DOI:10.11975/j.issn.1002-6819.2018.20.021
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 5>
Accession number:20190206357048
Title:Simulation of meso-mechanism of silo unloading grain aching based on improved particle composition mechanical model
Authors:Feng, Yong (1); Li, Meng (1)
Author affiliation:(1) College of Engineering and Architecture, Henan University of Technology, Zhengzhou; 450001, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:286-293
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The silo has the advantages of small area, good sealing conditions, low circulation costs, low cost and etc. It is currently the leading warehouse type of grain storage in China. Most silos still use gravity-based discharging methods, however, arches often form during silo discharging, it causes the pressure that should have been taken from the bottom of the warehouse to the wall of the warehouse. As a result, cracks may form in the silo walls causing serious damage. In addition, when there are workers above the grain surface or when the arch is manually broken, the collapse of the arch will not only result in personal injury or death of the grain surface staff, but also may damage the warehouse structure and facilities in the warehouse. In recent years, with the development of building technology, the silo volume has been continuously increasing, the diameter and height of the silo have also become larger and larger, and the related accidents caused by unloading and arching silos have also become more frequent Silo arch accidents in Daqing 2013, Lanxi 2015, in Heilongjiang province, and in Jing County in 2016 in Anhui province, for example, have resulted in the destruction of some silo facilities and casualties. Existing studies have shown that silo unloading and arching are closely related to the internal and external friction of grain. However, in those studies, a single circular particle is used in the current discrete element simulation. The real contact area of simulated grain is much smaller. As such, the simulation cannot objectively reflect the grain of the unloading process. The frictional situation is also more difficult to restore the mesoscopic dynamic process of unloading grain arching. In this paper, based on the existing PFC3D discrete element program, the micro particle simulation dust with larger viscosity coefficient was added to create an improved particle for the defect that the internal friction force of the circular particle in the discrete element simulation was smaller than that in the real grain. We used geometric methods in the structural mechanics model to determine the contact between the circular particles and derives the force-displacement relationship between the basic units. Based on typical accident cases and laboratory test results, the established particle structure mechanics model was used to simulate the force-displacement relationship between circular large particles and between small round particles and walls in the dynamic process of unloading grain and arching. The displacement map of shear stress and its stress characteristic curve were basically consistent with the experimental results. By using this model, the dynamic meso-mechanism of unloading and arching silos can be objectively reflected. The improved particle structure mechanics model proposed in this paper can not only be used to simulate the unloading and arching mechanism simulation, but also has certain reference value for the simulation of the characteristics of loose particles flow and the mechanism of the interaction between the bulk and the silo wall.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:30
Main heading:Unloading
Controlled terms:Accidents - Arches - Finite difference method - Friction - Mechanical properties - Mechanisms - Models - Shear stress - Walls (structural partitions) - Warehouses
Uncontrolled terms:Building technologies - Discrete element simulation - Force-displacement relationships - Mechanism simulation - Meso-scopic mechanis - Stress characteristics - Structural mechanics models - Viscosity coefficient
Classification code:408.2 Structural Members and Shapes - 601.3 Mechanisms - 691.2 Materials Handling Methods - 694.4 Storage - 914.1 Accidents and Accident Prevention - 921.6 Numerical Methods - 951 Materials Science
DOI:10.11975/j.issn.1002-6819.2018.20.036
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 6>
Accession number:20190206357042
Title:Nutrient characteristics of biochar prepared from animal manures at different temperature with limited oxygen
Authors:Wang, Huangping (1, 2); Zhang, Qing (1, 2); Zhang, Zande (3); Luo, Tao (4); Weng, Boqi (4); Zhong, Shaojie (1, 2)
Author affiliation:(1) Institute of Soil and Fertilizer, Fujian Academy of Agricultural Sciences, Fuzhou; 350013, China; (2) Land Cultivation Engineering Technology Research Center, Fuzhou; 350013, China; (3) Datian Crop Land Construction and Soil and Fertilizer Station, Datian; 366100, China; (4) Agricultural Ecology Institute, Fujian Academy of Agricultural Sciences, Fuzhou; 350013, China
Corresponding author:Luo, Tao(luotaofjfz@188.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:233-239
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Compared with traditional manure composting, the pyrolysis of livestock manures is one of the thermochemical technologies for converting biomass into nutrient-rich biochars with potential agronomic uses, and reduces the environmental problems caused by fecal accumulation. Studies are needed to clarify biochar nutrients properties across manure varieties under similar controlled conditions. Of all parameters affected the biomass pyrolysis process, temperature is one of the most important factors. In this study, three types of biochars derived from chicken manure (CM), solid-liquid separated pig manure (PR) and dairy manure (DM), were prepared by pyrolyzing at different temperatures (350, 450, 550, 650 and 750℃), under an oxygen-limited condition in muffle furnace. The effects of temperature on the ash content, total carbon content, macro to micro nutrients contents and their remaining rate of biochars were analyzed. Meanwhile, the C/N ratio, the correlation of nutrient contents between raw materials and carbonized products, and the relationship between pyrolysis temperature and nutrient characteristics of biochars were also discussed. The results showed, as pyrolysis temperature increased, the biochar carbon (C) and nitrogen (N) contents decreased, while the contents of ash, phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn) in biochars gradually increased. When pyrolysis temperature reached 750℃, the C and N contents decreased by 8.25%-19.86% and 59.62%-70.71%, respectively. Due to the decrease of volatile matter contents, the increased ash contents ranged from 43.28% to 57.65% at this temperature. The contents of P, K, Ca, Mg, Fe, Mn in biochars increased by 85.84%-128.54%, 85.03%-123.26%, 68.66%-169.03%, 33.02%-123.30%, 63.92%-103.62% and 56.92%-75.19% at 750℃, respectively. All nutrient differences reached a significant level (P<0.05). Although high temperature pyrolysis increased the total nutrient content and C/N ratio of manure-derived biochars, it also reduced the remaining rate of nutrients. When the pyrolysis temperature increased from 350 to 750℃, the residue rates of C, N, P and K in biochars decreased significantly by 58.25%-76.07%, 85.01%-88.23%, 33.31%-69.54% and 40.27%-71.29% (P<0.05), respectively. Those of Ca, Mg, Fe and Mn also reduced significantly by 45.18%-71.21%, 47.22%-73.52%, 40.84%-70.91% and 39.19%-68.11% (P<0.05). In general, the nutrient contents and their remaining rates in biochars were closely related to material source and pyrolysis temperature, and the correlation between nutrient characteristics and pyrolysis temperature was significant (P<0.05). Therefore, the selection of high C and high nutrient contents of animal manure, was the basis for improving the biochar nutrient contents, and suitable temperature was the key to retain the high nutrient residue rates of biochars. When the temperature increased from 450 to 550℃, the nutrients loss rates ranged from 20.12% to 71.23%, and the decrease was most obvious, indicating that the suitable temperature for manure pyrolysis was 450℃. Overall characteristics of biochar nutrients at this temperature, the selection of livestock manures for nutrient-rich biochars production was in order of DM > PR > CM in this study. Future studies focusing on other factors and the persistence of biochar fertility in the field must explicitly take into account additional factors to transfer this technology.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:34
Main heading:Nutrients
Controlled terms:Animals - Carbon - Environmental technology - Fertilizers - Forestry - Manures - Oxygen - Pyrolysis - Temperature
Uncontrolled terms:Animal manure - Bio chars - Controlled conditions - Effects of temperature - Environmental problems - High-temperature pyrolysis - Overall characteristics - Thermochemical technologies
Classification code:454 Environmental Engineering - 641.1 Thermodynamics - 802.2 Chemical Reactions - 804 Chemical Products Generally - 821.5 Agricultural Wastes
Numerical data indexing:Percentage 2.01e+01% to 7.12e+01%, Percentage 4.33e+01% to 5.76e+01%, Percentage 4.52e+01% to 7.12e+01%, Percentage 5.69e+01% to 7.52e+01%, Percentage 5.82e+01% to 7.61e+01%, Percentage 5.96e+01% to 7.07e+01%, Percentage 8.25e+00% to 1.99e+01%, Percentage 8.58e+01% to 1.29e+02%
DOI:10.11975/j.issn.1002-6819.2018.20.030
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 7>
Accession number:20190206357043
Title:Preparation of modified hierarchical HZSM-5 catalyst and its application on pyrolysis of biomass to enhance aromatics products
Authors:Zheng, Yunwu (1); Yang, Xiaoqin (1); Shen, Huajie (1); Huang, Yuanbo (1); Liu, Can (1); Zheng, Zhifeng (1)
Author affiliation:(1) University Key Laboratory for Biomass Chemical Refinery & Synthesis, College of Materials Science and Engineering, Southwest Forestry University, Kunming; 650224, China
Corresponding author:Zheng, Zhifeng(zhengzhifeng666@163.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:240-249
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Biomass catalytic pyrolysis vapor upgrading is an important way for converting biomass to high-value chemical products. Studies on pyrolysis behavior and products distribution of biomass are of great importance to the research on the interactions and catalytic conversion mechanism between model components of biomass and catalyst. At the same time, aromatic hydrocarbon compounds was the important chemical in nowadays, catalytic pyrolysis process produces a highly oxygenated bio-oil containing over 100 different compounds. The selectivity of fast pyrolysis can be greatly enhanced through the use of a catalyst, in particular with HZSM-5 zeolite which gives the highest selectivity toward mono-cyclic platform aromatics (such as benzene, toluene, xylene and ethyl benzene) essential to the chemical industry. Despite this high selectivity, a significant fraction of the freed-stock's renewable carbon is lost to coke and char, two undesired byproducts. Coke formation has been attributed to the polymerization of small oxygenates on the external surface of the zeolite and to the formation of polyaromatic hydrocarbons through condensation reactions inside the micropores. So in order to improve selectivity toward desired products of aromatic and lower the formation of coke, the mesoporous HZSM-5 was synthesized by desilication method. In this paper, we used alkali treatment of commercial HZSM-5 zeolites using K<inf>2</inf>CO<inf>3</inf> solutions to introduce mesopores into microporous system, and to investigate the effects of alkali concentration (0.2-0.6 mol/L) on aromatics yield and selectivity, The pyrolysis of experimental sample (pine, cellulose and lignin) was conducted in a fixed bed reactor with the conditions of pyrolysis temperature of 450℃, and catalytic temperature of 550℃, the ratio of biomass to catalyst of 1:2. Materials and products characteristics were investigated with various testing approaches, such as elements analysis, X-ray diffraction (XRD), surface area and pore size analyzer (BET), scanning electron microscope (SEM), Fourier infrared spectroscopy (FTIR), X-ray photoelectron spectrometer (XPS), temperature programmed desorption (NH<inf>3</inf>-TPD) and gas chromatography mass spectrograph (GC-MS) to study the effect of desilication on the structure, acidity, pore size and performance of aluminum-rich ZSM-5 as well the product distribution of pyrolysis bio-oil. The results showed that alkali treatment of HZSM-5 can remove the extra-framework Si species to enhance the diffusion property, and at the same time, creation the mesopores, and the pore diameter of mesopores increased with the increase of K<inf>2</inf>CO<inf>3</inf> concentration however, the total acid amount decreased. Detailed characterization of the obtained zeolite catalysts indicated that mild desilication conditions significantly affect the elemental composition, crystallographic structure, microporosity, and distribution of aluminum atoms in framework and extra framework sites. The number of accessible Brønsted acid sites increased as a result of the enhanced mesoporosity. At the same time, the concentration of alkali solution, the corrosion degree, the degree of desilication and desilication, and the mesoporous degree increased, as such the hysteresis phenomenon became more and more obvious. Moreover, the hierarchical HZSM-5 catalyst produced more aromatic hydrocarbons and less coke formation in CFP of lignin and lignocelluloses' biomass that contained the lignin component than that of the control HZSM-5, which effectively improved the selectivity for naphthalene family products (methylnaphthalene and 2-methylnaphthalene) in the bio-oil and decreased the content of aromatic hydrocarbons larger than C10. The highest aromatic yield (82.81%) and lowest coke yield (28.06%) were obtained in CFP of pine wood with mildly desilicated zeolite treated with 0.5mol/L K<inf>2</inf>CO<inf>3</inf> solution.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:36
Main heading:Catalyst selectivity
Controlled terms:Aluminum - Ammonia - Aromatization - Benzene - Biofuels - Biomass - Cellulose - Chemical industry - Chemical reactors - Coke - Condensation reactions - Corrosion - Crystal atomic structure - Fourier transform infrared spectroscopy - Gas chromatography - Hydrocarbons - Lignin - Mass spectrometry - Microporosity - Mineral oils - Naphthalene - Oil well testing - Pore size - Potash - Pyrolysis - Scanning electron microscopy - Spectrometers - Temperature programmed desorption - Zeolites
Uncontrolled terms:Aromatic - Catalytics - Crystallographic structure - H-zsm-5 catalysts - K2CO3 treatment - Polyaromatic hydrocarbons - Products distributions - X ray photoelectron spectrometers
Classification code:511.1 Oil Field Production Operations - 513.3 Petroleum Products - 524 Solid Fuels - 541.1 Aluminum - 741.3 Optical Devices and Systems - 801 Chemistry - 802 Chemical Apparatus and Plants; Unit Operations; Unit Processes - 803 Chemical Agents and Basic Industrial Chemicals - 804 Chemical Products Generally - 805 Chemical Engineering, General - 811.3 Cellulose, Lignin and Derivatives - 931.2 Physical Properties of Gases, Liquids and Solids - 931.3 Atomic and Molecular Physics
Numerical data indexing:Molar_Concentration 2.00e+02mol/m3 to 6.00e+02mol/m3, Percentage 2.81e+01%, Percentage 8.28e+01%
DOI:10.11975/j.issn.1002-6819.2018.20.031
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 8>
Accession number:20190206357038
Title:Effects of drinking water temperature on growth performance and behavior of weaned piglets in winter
Authors:Zhang, Zhi (1, 2, 3); Liang, Liping (1, 2, 3); Li, Baoming (1, 2, 3); Zhao, Wanying (1, 2, 3); Zheng, Weichao (1, 2, 3)
Author affiliation:(1) Key Laboratory of Agricultural Engineering in Structure and Environment, Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing; 100083, China; (2) College of Water Resources and Civil Engineering, China Agricultural University, Beijing; 100083, China; (3) Beijing Engineering Research Center for Animal Healthy Environment, Beijing; 100083, China
Corresponding author:Zheng, Weichao(weichaozheng@cau.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:204-209
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Temperature of drinking water is one of the main factors affecting performance of piglets but it seldom arouses attention by producers. Inappropriate temperature of drinking water can not only have negative impact on welfare and health, but also increase the occurrence of intestinal diseases, resulting in significant economic losses in large-scale piglets production. It was required to settle the urgent issue on how to provide the suitable drinking water temperature, and explain the relationship between drinking water temperature and piglet performance. The objective of this study is to find out the suitable temperature of drinking water for weaned piglets, and provide the drinking water under a constant temperature for the piglets. An automatic drinking water heating apparatus was developed to provide drinking water under a constant temperature, and this water heating equiped with temperature sensor and temperature controller. It was important to analyze the thermal characteristics of drinking water supply pipeline, in order to obtain the relationship between the indoor air temperature, the volume of insulated bucket and the setting inlet temperature of the drinking water pipeline. This relationship can provide a guidance for the uniformity of drinking water supply pipeline in different indoor temperatures. The experiments were conducted in a large-scale pig house located at Jiangsu, and at three levels of different drinking water temperature (13, 25 and 30℃). Each level was repeated 4 times, and 10 heads of weaned piglets (120 heads of piglets in total) were selected for each trial. The average indoor temperature and relative humidity was 21.5℃ and 63% in the experiment, respectively. The average daily weight gain (ADG), average daily feed intake (ADFI) and ratio of feed to gain (F/G), water intake, diarrhea rate and morbidity rate (MBR) of weaned piglets in each group were recorded. The frequency and time of various behaviors were also monitored using cameras and digital behavior image recorders in the peak period of drinking and feeding (08:30-09:30, 14:30-15:30). And we randomly selected 12 heads of weaned piglets marked with colorful pen in every test groups. The results showed that: 1) Compared with the control group of drinking water temperature at 13℃, the experiment group of 25℃ could significantly improve the time and frequency of drinking, and significantly increased the water intake of weaned piglets (P<0.05). 2) The drinking water temperature had no significant effect on the daily consumption of weaned pigs (P<0.05), but the group of 25℃ could significantly improve ADG, and reduce F/G (P<0.05). The ADG of 25℃ increased by 23.2% compared with the control group of 13℃, the F/G of 25℃ drinking water group was 14.7% lower than that of the group of 30℃ and 13℃. 3) Compared with the control group of 13℃, the group of 25℃ and 30℃ could significantly reduce the diarrhea rate by 65.2% and 23.7%, reduce the morbidity rate by 58.4% and 34.0% (P<0.05), respectively. 4) The walking behavior frequency was higher than drinking and feeding behavior, and the group of 25℃ was higher than that of the other groups significantly (P<0.05), but the feeding frequency had no significant differences among the three groups. Results of this study provide a theoretical reference for setting a suitable drinking water temperature of weaned piglets and expected to improve animal welfare.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:27
Main heading:Potable water
Controlled terms:Diseases - Feeding - Heating - Inlet flow - Losses - Pipelines - Space heating - Temperature - Thermal processing (foods) - Water - Water pipelines - Water supply
Uncontrolled terms:Apparatus - Behavior - Growth performance - Indoor air temperature - Temperature controllers - Thermal characteristics - Time and frequencies - Weaned piglets
Classification code:444 Water Resources - 446.1 Water Supply Systems - 619.1 Pipe, Piping and Pipelines - 631.1 Fluid Flow, General - 641.1 Thermodynamics - 643.1 Space Heating - 691.2 Materials Handling Methods - 822.2 Food Processing Operations - 911.2 Industrial Economics
Numerical data indexing:Percentage 1.47e+01%, Percentage 2.32e+01%, Percentage 2.37e+01%, Percentage 5.84e+01%, Percentage 6.30e+01%, Percentage 6.52e+01%
DOI:10.11975/j.issn.1002-6819.2018.20.026
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 9>
Accession number:20190206357044
Title:Effects of clay and chemical additives on nitrogen retention during cow manure composting
Authors:Gao, Binbin (1); Wang, Xuan (2); Chang, Ruixue (1); Chen, Qing (1)
Author affiliation:(1) Beijing Key Laboratory of Farmland Soil Pollution Prevention-control and Remediation, College of Resource and Environmental Sciences, China Agricultural University, Beijing; 100193, China; (2) Key Laboratory of Agricultural Water Resources, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang; 050021, China
Corresponding author:Chen, Qing(qchen@cau.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:250-257
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Composting is an environmentally friendly technology to convert livestock manure to stable and nutritional organic fertilizer. However, significant N losses through NH<inf>3</inf> emission during composting reduce nutrient value and cause air pollution. Several studies attempt to decrease the nitrogen loss with additives addition, but a comprehensively assessment on N conservation efficiency of additives with different characters is lacking. In this study, chemical substances (calcium oxide (CaO), magnesium oxide (MgO), ferrous sulfate (FeSO<inf>4</inf>), alum (KAl(SO<inf>4</inf>)<inf>2</inf>),) and clay mineral (vermiculite, zeolite, medical stone, bentonite) were used in composting with cow manure and corn stalk as feedstock, with the purpose to study their potential effects on ammonia emission and compost maturity. The addition ratio of additives was 2.5% of compost material (dry weight base). The emissions of NH<inf>3</inf> and inorganic nitrogen were monitored during 35-day composting process, together with the pH, EC value, the total organic carbon and the maturity index (Germination Index, GI). Solid samples were taken at various stages (0, 3<sup>rd</sup>, 7<sup>th</sup>, 10<sup>th</sup>, 14<sup>th</sup>, 21<sup>st</sup>, 28<sup>th</sup>, 35<sup>th</sup> day) of composting. The results showed that the thermophilic phase (above 50℃) in all the treatment lasted more than 10 days during composting, suggesting that the product had met the requirements of harmless based the standard GB 7959-2012. Compared with the control treatment, the addition of chemical substances CaO and MgO had no effect on ammonia emission and nitrogen losses, while the addition of FeSO<inf>4</inf> and KAl(SO<inf>4</inf>)<inf>2</inf> decreased the ammonia emissions and nitrogen losses by 43.7%, 30.0% and 33.8%, 26.5%, respectively. The addition of vermiculite, zeolite, medical stone, and bentonite decreased the ammonia emissions and nitrogen losses by 24.4%, 29.9%, 7.1%, 20.1% and 15.4%, 22.9%, 2.2%, 13.4%, respectively. Little influences of different additives were found on EC value of compost products. The addition of MgO greatly increased the pH, which resulted in the germination index of the compost product lower than 50% at the end of process, while the other additives had little effect on pH changing and no influence on getting maturity after 35 days composting. In summary, the chemical substrates FeSO<inf>4</inf> and KAl(SO<inf>4</inf>)<inf>2</inf> had been considered as more superior additives to conserve nitrogen in composting process without influence on physiochemical characters and compost maturity, when compared than the other six additives. However, the clay minerals are normally cheaper than chemical substrates. So that clay minerals had a higher overall efficiency, but factories could choose different conditioners according to their requirement for the quality or for the cost in practice.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:36
Main heading:Additives
Controlled terms:Aluminum compounds - Ammonia - Bentonite - Clay minerals - Composting - Cultivation - Efficiency - Fertilizers - Iron compounds - Lime - Magnesia - Manures - Nitrogen - Organic carbon - pH - Sulfur compounds - Zeolites
Uncontrolled terms:Chemical additive - Chemical substance - Composting process - Environmentally-friendly technology - Mineral additives - Nitrogen loss - Organic fertilizers - Total Organic Carbon
Classification code:482.2 Minerals - 801.1 Chemistry, General - 803 Chemical Agents and Basic Industrial Chemicals - 804 Chemical Products Generally - 821.3 Agricultural Methods - 821.5 Agricultural Wastes - 913.1 Production Engineering
Numerical data indexing:Age 2.74e-02yr, Age 9.59e-02yr, Percentage 1.34e+01%, Percentage 1.54e+01%, Percentage 2.01e+01%, Percentage 2.20e+00%, Percentage 2.29e+01%, Percentage 2.44e+01%, Percentage 2.50e+00%, Percentage 2.65e+01%, Percentage 2.99e+01%, Percentage 3.00e+01%, Percentage 3.38e+01%, Percentage 4.37e+01%, Percentage 5.00e+01%, Percentage 7.10e+00%
DOI:10.11975/j.issn.1002-6819.2018.20.032
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 10>
Accession number:20190206357014
Title:Design and test of screw cleaning mechanism for corn
Authors:Wang, Qiyang (1); Wu, Wenfu (1); Zhu, Haotian (1)
Author affiliation:(1) College of Biological and Agriculture Engineering, Jilin University, Changchun; 130022, China
Corresponding author:Wu, Wenfu(wwfzlb@126.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:12-19
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Screening is the most important part of post-harvest processing of grain, and it is mainly vibration screening. Traditional methods of vibration screening have many problems, such as large noise and low screening efficiency. The aim of this article was to solve the problem mentioned above in the traditional screening process, and the screw cleaning mechanism was designed based on the principle of screw conveying. The device was mainly composed of conveying auger, inlet charge hopper, frame, collection box, semicircular screen, discharge port, gear motor, variable-frequency drive, and so on. In terms of mechanism parameters, the inner diameter of semicircular screen was 130 mm, the external diameter of the conveying auger was 100 mm, the screw pitch was 100 mm, the working length was 2 000 mm, and the diameter of screw shaft was 20 mm. There were 2 types of semicircular screens, the first one was 6 mm circular aperture with the open porosity of about 40%, and the other one was 16 mm circular aperture with the open porosity of about 35%. The critical screw rotational speed was 205 r/min, and the maximum theoretical cleaning ability of the device was 6.8 t/h. In order to determine the screening effect of the device, the screening efficiency and the breakage rate increment were used as the test indices in this study, and the corn with 14% moisture was adopted in the test, which included the separation test of big-sized impurities and the separation test of small-sized impurities. In terms of separation test of big-sized impurities, it was a single-factor test. Appropriately sized corn cobs and stalks were selected as big impurities. Test samples were prepared according to the relevant standards, and corn samples were obtained, of which big-sized impurities content was 2%. The conveying inclination was 0°, the initial filling factor was 40%, the working length was 960 mm, and 30 kg corn samples were tested each time. The results of the separation test of big-sized impurities showed that screening separation occurred mainly at the front portion of the screen, and the main function of the latter portion of the screen was to separate corn entrained by corn cobs and stalks; and the breakage rate increased with the increase of the screw rotational speed. Although lower screw rotational speed reduced cleaning ability, it could protect corn from break, and higher screw rotational speed might increase the working length of the screen surface. For the separation test of small-sized impurities, the clay granules which had passed through 3 mm circular aperture grain sieve were selected as small-sized impurities and the test samples were also prepared according to the relevant standards; corn samples were obtained, of which small-sized impurities content was 5%, and 30 kg corn samples were tested each time. The single-factor test showed that screening efficiency and breakage rate increment increased with the increase of the conveying auger speed; with the increase of the initial filling factor, screening efficiency decreased slowly, but breaking rate increment increased gradually; screening efficiency increased initially and decreased afterwards as the conveying inclination increased, and breaking rate increment increased gradually. The orthogonal test selected conveying inclination (-10°, 0°, 10°), screw rotational speed (150, 200, 250 r/min) and initial filling factor (20%, 30%, 40%) as the test factors, and 9 groups of experiments were conducted. The orthogonal test results showed the optimal test levels of the 3 experimental factors: Initial filling factor was 20%, conveying inclination was 0°, and screw rotational speed was 500 r/min. The ANOVA (analysis of variance) results showed that initial filling factor had significant (P<0.05) influence on screening efficiency, but it didn't have significant (P>0.05) influence on breakage rate increment; screw rotational speed had significant (P<0.05) influence on both screening efficiency and breakage rate increment; but conveying inclination didn't have significant (P>0.05) influence on either screening efficiency or breakage rate increment. The device had low noise and reliable operation in working process, and screening efficiency of the device reached 98.5%. This study can provide reference for the design of the screw cleaning equipment in the future.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:32
Main heading:Testing
Controlled terms:Augers - Cleaning - Design - Efficiency - Filling - Grain (agricultural product) - Mechanization - Optimization - Porosity - Screening - Screws - Separation - Speed - Variable speed drives
Uncontrolled terms:ANOVA (analysis of variance) - Breakage rates - Experimental factors - Mechanism-parameters - Postharvest processing - Screening efficiency - Variable frequency drives - Vibration screenings
Classification code:502.2 Mine and Quarry Equipment - 601 Mechanical Design - 602.1 Mechanical Drives - 605 Small Tools and Hardware - 691.2 Materials Handling Methods - 802.3 Chemical Operations - 821.4 Agricultural Products - 913.1 Production Engineering - 921.5 Optimization Techniques - 931.2 Physical Properties of Gases, Liquids and Solids
Numerical data indexing:Mass 3.00e+01kg, Mass_Flow_Rate 1.71e+00kg/s, Percentage 1.40e+01%, Percentage 2.00e+00%, Percentage 2.00e+01%, Percentage 3.00e+01%, Percentage 3.50e+01%, Percentage 4.00e+01%, Percentage 5.00e+00%, Percentage 9.85e+01%, Rotational_Speed 2.05e+02RPM, Rotational_Speed 2.50e+02RPM, Rotational_Speed 5.00e+02RPM, Size 1.00e-01m, Size 1.30e-01m, Size 1.60e-02m, Size 2.00e+00m, Size 2.00e-02m, Size 3.00e-03m, Size 6.00e-03m, Size 9.60e-01m
DOI:10.11975/j.issn.1002-6819.2018.20.002
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 11>
Accession number:20190206357047
Title:Development of arching and silo wall pressure distribution in storage and discharging state based on discrete element analysis
Authors:Liu, Kejin (1); Xiao, Zhaoran (1); Wang, Shihao (1)
Author affiliation:(1) School of Civil Engineering and Architecture, Henan University of Technology, Zhengzhou; 450001, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:277-285
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:It has been widely recognized that the most dangerous condition is the phenomenon that the emptying pressure on the wall of silos vibrates and increases obviously during discharging. However, the cause of this phenomenon is currently largely unknown. Most of the available papers and reports are based on continuum mechanics, that is, the stored material is regarded as a continuous entity on macroscopic level, and its particulate property is ignored. In fact, it is the microcosmic mechanical behavior of individual particles and the interaction between the particles and the silo walls that determine the emptying pressure distribution on the silo walls. Therefore, in this paper, the characteristics of emptying pressure were studied from the point of view of granular materials and microcosmic particle mechanics. A new method combining particle mechanics with discrete element method (DEM) was introduced to explore how the mechanical behavior of particles effects the distribution of emptying pressure. Firstly, the behavior of granular material in stored state was studied by DEM method. The silo with flat bottom is 0.5 m in diameter, 1.0 m in height and 0.1 m in outlet diameter, which is filled with 20 400 spherical particles. The distribution of the static wall pressure in stored state was verified by the test results and the Jassen Formula which is widely used in engineering. Secondly, the pressure distribution on the silo bottom wall was studied by simulating the discharge process, and the statistical analysis of multiply simulation results was performed, the arching effect near the outlet were proved according to the periodic pressure profile. Thirdly, in order to study the arching effect, three time points, i.e. start of arching, completion of arching and arch collapse, were selected on the periodic pressure profile. For each time point, the behaviors, such as force chain network, vertical stress distribution, and lateral stress distribution, the direction of principal stress, velocity field of granular material and so on, were systematically studied. On this basis, the features and evolution mechanism of the arching effect were investigated from the viewpoint of particle mechanics. Finally, the static pressure under the static stored state and the emptying pressure in discharging process on the silo wall were analyzed and verified by a model test, Standards (GB50322-2011) and published results. The results indicated that the arch which is 4.0 times wide of outlet diameter and 2.5 times high of outlet diameter was produced during the discharge process. Due to the formation of arching, the vertical stress above arching was transformed into the horizontal stress in a certain range above the arch foot, thus the horizontal stress was transferred to both sides of the silo wall and to the pressure of the silo wall was increased. When the arching collapsed, the vertical and horizontal above arching decreased, then the horizontal stress transferred to both sides of the silo wall also decreased, which resulted in to the decrease of wall pressure. The coefficient of overpressure reached a peak value of 2.70 at depth ratio of 0.35, while the peak wall pressure was 3.57 kPa at depth ratio of 0.85. It was found that the arching effect near the outlet behaved dynamically, following the rule of "start of arching-completion of arching-collapse of arch", thus the dynamic arching effect is put forward. In addition, the important connection between the dynamic arching effect and the resulting emptying pressure distribution was identified. That is, the increased emptying pressure on silo wall is caused by the formation of arch, while the vibration of emptying pressure on wall of silo is induced by the dynamic arching effect. The research provides a new method of exploring the relationship between the arching effect and the emptying pressure distribution on wall of silos from the micro and macro aspects. The findings obtained in this paper can provide references for revealing the load-transfer mechanism from particles to silo wall.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:34
Main heading:Walls (structural partitions)
Controlled terms:Arches - Continuum mechanics - Dynamics - Finite difference method - Granular materials - Micromechanics - Numerical methods - Particles (particulate matter) - Pressure distribution - Pressure effects - Silos (agricultural) - Stress concentration - Stresses - Velocity
Uncontrolled terms:Discrete element analysis - Evolution mechanism - Force chain networks - Individual particles - Load transfer mechanism - Mechanical behavior - Soybean - Wall pressure
Classification code:408.2 Structural Members and Shapes - 821.6 Farm Buildings and Other Structures - 921.6 Numerical Methods - 931.1 Mechanics - 951 Materials Science
Numerical data indexing:Pressure 3.57e+03Pa, Size 1.00e+00m, Size 1.00e-01m, Size 5.00e-01m
DOI:10.11975/j.issn.1002-6819.2018.20.035
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 12>
Accession number:20190206357045
Title:Evaluation of intensive urban land use and analysis of obstacle factors in northern slope of Tianshan mountains
Authors:Zhao, Huishun (1); Chen, Chao (1); Hu, Zhenqi (1); Li, Luman (2)
Author affiliation:(1) Institute of Land Reclamation and Ecology, China University of Mining and Technology (Beijing), Beijing; 100083, China; (2) College of Science, Shihezi University, Shihezi; 832000, China
Corresponding author:Hu, Zhenqi(huzq@cumtb.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:258-266
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Land is the spatial carrier of a city's society, economy and ecosystem. Intensive urban land use is an important means to improve land use efficiency, which is of great significance for optimizing the allocation of urban land resources and promoting the coordinated development of urban society, economy and ecology. In this manuscript, considering the regional characteristics, economic status and land use characteristics of the four cities (i.e. Urumqi, Karamay, Shihezi, and Changji) in the northern slope of the Tianshan Mountains, we selected 16 indicators from three aspects of economic-society-ecological factors to establish an evaluation index system for intensive land use. In order to compare the intensive degrees between four cities, a global standardized data table (X' ij)<inf>16×9×4</inf> was established by a multivariate standardization method, based on the original data of four cities' evaluation indicators, which provide a unified data base for the intensive use of land in the four cities on the northern slope of the Tianshan Mountains. In addition, the optimal combination weighting method was employed to assign weights for four cities' evaluation indicators, respectively, which was the integration of subjective weighting (AHP) and objective weighting (Entropy weighting method) via the Lagrange multiplier method. This approach of weighting gives consideration to the subjective and objective factors of the studied area and more accurately reflects the locational differences of different cities. On this basis, multi-factor comprehensive evaluation was taken to calculate the intensive degrees of four cities, and to evaluate the status of land intensive by the four-level evaluation criteria, i.e. highly intensive, moderately intensive, marginally intensive, and not intensive. Moreover, a coordination model based on benefit theory and balance theory, and an obstacle model were introduced to analyze the coherence and obstacle factors, respectively, and to explore the main obstacles that affected urban land intensive, aiming to provide guidance for the development of intensive urban land use. Our findings revealed that: 1) The intensity of land use in the four cities showed an overall upward trend from 2008 to 2016, the mean value of intensity were in the order of Karamay City (0.562) > Shihezi City (0.532) > Changji City (0.512) > Urumqi City (0.476). There was still much room for improvement in the marginal-intensive land use (III). 2) The degree of land intensity and coordination had a strong correlation with a consistent evolution trend generally. According to the average degree of internal coordination, rankings were Karamay City (0.594) > Changji City (0.591) > Shihezi City (0.502) > Urumqi City (0.466). 3) From the perspective of obstacles, the status of obstacles in the four cities varied, but the overall performance was economic obstacle > social obstacle > ecological obstacle, and the degree of ecological obstacle continued to decrease. There were certain regional differences in various obstacle factors affecting urban land intensive, but the GDP-based economic indicators and population-based social indicators were the main obstacles overall. The results indicated that the assessment of land intensive use based on the optimal combination weighting method not only guaranteed the unity of comparison, but also reflected the difference in location, thus achieving an in-depth analysis of the factors affecting obstacle degree and the evolution of urban land intensive use accurately and effectively.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:37
Main heading:Land use
Controlled terms:Ecology - Economics - Entropy - Factor analysis - Lagrange multipliers - Landforms - Location - Stream flow
Uncontrolled terms:Coordination degree - Entropy weight method - Northern slope of Tianshan mountains - Obstacle degree - Optimal combination
Classification code:403 Urban and Regional Planning and Development - 407.2 Waterways - 454.3 Ecology and Ecosystems - 481.1 Geology - 641.1 Thermodynamics - 922.2 Mathematical Statistics - 971 Social Sciences
DOI:10.11975/j.issn.1002-6819.2018.20.033
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 13>
Accession number:20190206357015
Title:Pitching attitude closed loop control of wheel-legged all terrain mobile robot with active suspension
Authors:Ma, Fangwu (1, 2); Ni, Liwei (1, 2); Wu, Liang (1, 2); Nie, Jiahong (1, 2)
Author affiliation:(1) College of Automotive Engineering, Jilin University, Changchun; 130012, China; (2) State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun; 130012, China
Corresponding author:Wu, Liang(15143185852@163.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:20-27
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:With the attention of agricultural robot research and development in recent years, many kinds of agricultural robots have been developed according to the different focus of the problem solving. Because the wheel-legged robots have excellent obstacle surmounting ability, low energy consumption and stable terrain adaptability compared with other mobile platforms, it has been widely used in various fields of precision agriculture, military investigation, resource exploration and so on. The position and attitude will be inevitably changed when the wheel-legged robots in operation, and the working accuracy and working performance will be affected due to the complexity of the working environment. In order to control the position and attitude, reduce the influence of the non paved pavement to the robot's attitude and position, ensure the stability of the robot, a new type of wheel-legged all terrain mobile robot with active suspension was designed in this study based on the multi-link independent suspension system of the vehicle. Multi-link independent suspension had mature application experience in automobile manufacture, but seldom applied in wheel-legged robot. The suspension system was the general name of the device that connected the body and the wheel. It can be roughly divided into the independent suspension system and the dependent suspension system, of which the non independent suspension system referred to the connection between the two wheels, and the pulsation of one side of the wheel affected the beat of the other side, while the wheels in the multi-link independent suspension system had their respective suspension mechanisms, which were independent of each other and did not interfere with each other, this improved the stability and comfort of the robot. By the suspension system, the vibration of the robot can be effectively reduced, the impact between the parts of the robot was buffered, and the economy and reliability of the robot can be improved. Then on the basis of establishing the kinematics model of wheel-legged robot, the inverse kinematic equations was established by Vector method and Euler formula, and the relationship between actuator stroke and suspension rotation angle was obtained, meanwhile, the position and attitude control of wheel-legged robot was decoupled. In order to ensure the reliability and correctness of the inverse kinematics and kinematics control model of the robot, the 1/4 robot test rig was manufactured and a 1/4 bench model test was carried out on the basis of theoretical analysis. The simulation results were basically consistent with the bench test data, and the maximum error was within 1.5%, the correctness of the relationship between the motion pitch angle of the robot body and the rotation angle of each leg joint was verified under the condition of the participation of the kinematic model. Then, a robot pitching attitude control strategy was built in MATLAB with proportional control to realize the closed loop control under the condition that the center of robot centroid was fixed, Finally, the robot virtual model was built in ADAMS, and MATLAB and ADAMS were used to establish the joint simulation. The simulation results showed that the pitch attitude and the centroid position of the robot had a good tracking effect, and the position error and attitude error of the centroid were 0.2% and 2%, respectively. Therefore, the correctness of the closed-loop attitude control strategy of the wheel-legged robot was verified. The algorithm can maintain the position and attitude of the wheel-legged robot and reduced centroid offset when crossing obstacles, it enhanced the performance of wheel-legged robot as the agricultural robot, the performance of the all terrain mobile robot with active suspension provides a reference for the design of the motion position and attitude control of the modern agricultural robot.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:33
Main heading:Suspensions (components)
Controlled terms:Active suspension systems - Agriculture - Attitude control - Automobile bodies - Automobile manufacture - Closed loop control systems - Control engineering - Energy utilization - Errors - Inverse kinematics - Inverse problems - Kinematics - Landforms - Machine design - MATLAB - Mobile robots - Models - Off road vehicles - Problem solving - Reliability analysis - Robots - System stability - Wheels
Uncontrolled terms:All-terrain mobile robots - Application experiences - Economy and reliabilities - Independent suspension system - Joint simulation - Low energy consumption - Position and attitude controls - Research and development
Classification code:481.1 Geology - 525.3 Energy Utilization - 601 Mechanical Design - 601.2 Machine Components - 662.1 Automobiles - 662.4 Automobile and Smaller Vehicle Components - 731.3 Specific Variables Control - 731.5 Robotics - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 921 Mathematics - 931.1 Mechanics - 961 Systems Science
Numerical data indexing:Percentage 1.50e+00%, Percentage 2.00e+00%, Percentage 2.00e-01%
DOI:10.11975/j.issn.1002-6819.2018.20.003
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 14>
Accession number:20190206357032
Title:Analyzing spatio-temporal variations of evapotranspiration in Dongting Lake Basin during 2000-2014 based on MOD16
Authors:Zhang, Meng (1, 2); Zeng, Yongnian (1, 2); Qi, Yue (1, 2)
Author affiliation:(1) School of Geosciences and Info-physics, Central South University, Changsha; 410083, China; (2) Center for Geomatics and Regional Sustainable Development Research, Central South University, Changsha; 410083, China
Corresponding author:Zeng, Yongnian(ynzeng@mail.csu.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:160-168
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:As an important part of ecological environment and water resources assessment, timely and accurate analysis of spatio-temporal characteristics of regional evapotranspiration and its relationship with climate factors, is of great significance to the regional weather, hydrology, water conservancy and agricultural fields. In this article, we analyzed the inter-annual variation and annual variation of surface evapotranspiration in the Dongting Lake Basin during 2000-2014 based on the time series MOD16 dataset. And the correlation between evapotranspiration and climate factors was discussed by using regression model based on the annual precipitation and temperature data of study area. The results show that: 1) Based on the measured evapotranspiration of Taoyuan station, we validated the MOD16 dataset. The correlation coefficient between the measured evapotranspiration and surface evapotranspiration from MOD16 was 0.88, which met the needs of accuracy of the study on the spatial and temporal distribution of evapotranspiration in Dongting Lake Basin; 2) The annual evapotranspiration value of Dongting Lake Basin has a strong spatial differentiation pattern, showing a trend of being low in the northeast area, and high in western and southern areas of the study area. During the study period, the average annual evapotranspiration in Dongting Lake Basin was 636.83 mm/a, which showed a downward trend with irregular fluctuations. The highest evapotranspiration value appeared in 2001, which was 669.19 mm/a, and the lowest evapotranspiration value was 613.62mm/a, which appeared in 2011. The change rate of annual surface evapotranspiration (θ) was -2.98%, which indicated that the evapotranspiration value showed a downward trend of Dongting Lake Basin. The spatial distribution of evapotranspiration was related to land cover types, which had effect on the evapotranspiration distribution in the Dongting Lake Basin, and the order of evapotranspiration intensity of different land cover types was forest > grassland > bare land > cultivated land > town. 3) The seasonal variation of evapotranspiration value was obvious, and the evapotranspiration in summer was the highest. The order of evapotranspiration value of different seasons was Summer > Spring > Autumn > Winter. 4) Furthermore, the annual variation of evapotranspiration in Dongting Lake Basin showed a unimodal pattern that increased first and then decreased. The high value area of monthly evapotranspiration was mainly concentrated between May and September, the minimum value appeared in December, and the peak value occurred in July. 5) The correlation coefficients between surface evapotranspiration and precipitation and temperature were 0.67 and 0.41, respectively. Most of the regional precipitation and temperature have a positive correlation with surface evapotranspiration in Dongting Lake Basin. Comparatively, the correlation between surface evapotranspiration and precipitation was stronger than that between surface evapotranspiration and temperature. The humid climatic condition is beneficial to the growth and development of vegetation. With the increase of vegetation coverage, the value of surface evapotranspiration also increases. However, a higher temperature and less precipitation, being not conducive to the growth of vegetation, results in low surface evapotranspiration. According to the above analysis of this article, it can be further explained that the coupling effect of temperature and precipitation is an important factor affecting the surface evapotranspiration in Dongting Lake Basin.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:33
Main heading:Evapotranspiration
Controlled terms:Climate models - Factor analysis - Lakes - Precipitation (chemical) - Regression analysis - Temperature - Vegetation - Water management
Uncontrolled terms:Annual evapotranspirations - Dongting Lake - MOD16 - Regional evapotranspiration - Spatial and temporal distribution - Spatio-temporal changes - Spatiotemporal characteristics - Surface evapotranspiration
Classification code:443 Meteorology - 641.1 Thermodynamics - 802.3 Chemical Operations - 921 Mathematics - 922.2 Mathematical Statistics
Numerical data indexing:Percentage -2.98e+00%
DOI:10.11975/j.issn.1002-6819.2018.20.020
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 15>
Accession number:20190206357041
Title:Simulation and verification of influence of different street vegetation structure on diffusion of atmosphere particulates
Authors:Wang, Jia (1, 2); Lü, Chundong (1, 2); Niu, Liwei (1, 2); Zhang, Fangfei (1, 2)
Author affiliation:(1) Beijing Key Laboratory of Precision Forestry, Beijing Forestry University, Beijing; 100083, China; (2) School of Forestry, Beijing Forestry University, Beijing; 100083, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:225-232
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:As the city is developing continuously recently, frequently occurred haze has increasingly raised residents' concerns about the urban ecological problems. Motor vehicle exhaust gas is one of the major sources of atmospheric particulates. The road green system, an important ecological measurement, which plays a significant role in preventing the motor vehicle exhaust gas diffusion, is of great significance to improve urban air quality and residents' life quality and the living environment. For the purpose of urban road greening plan, we used high resolution remote sensing images and street views to compile the road information tables so as to select six roads (Baiziwan Road, Linda North Road, Jiaodaokou East Avenue, Dongzhimen North Street, and Nongzhanguan South Road) in Beijing city as the sample set which represent different road green systems, green configurations and street aspect ratios. For the simulation experiment in this paper, we used three-dimensional microclimate software ENVI-met, which was based on fluid and thermodynamics (the calculation of the basic law of the fluid dynamics model), to simulate the interaction processes among ground, vegetation, building and atmosphere in a small-scale urban space. We constructed three-dimensional main model area and set main characteristic parameters of the sample places, such as building, greening and underlying surface structure, and achieved the numerical simulation of interactions among ground, vegetation, building and atmosphere by using the weather prediction subprogram to analyze governing equation. We conducted field experiment in order to compare it with the numerical simulation results. The monitoring points were set on the roadside and behind the tree respectively. Each experiment street was set with one monitoring section which has two monitoring points at the height of 1.5 meters. We selected PM10 as the monitoring item and measure meteorological factors such as wind speed, wind direction and temperature at the same time. We set the results of the non-vegetation particulate matter as background value and superposed it with the diffusion of that under different green configurations to analyze the law of particulate matter diffusion of different green configurations. The simulation results showed that, under the same condition of wind speed and wind direction, the changes of PM10 concentration on the leeward side of monitoring point were higher than that on its windward side, which proved that the motion of airflow caused the particulate matter accumulation on the leeward side and the spreading of particulate matter over the road as air flow rising, so the concentration of particles on the leeward side was the largest, and then gradually decreased as the building height increasing. Under the same condition of aspect ratio, the effect of arbor--shrub-grass configuration on reducing PM10 concentration was the most obvious, followed by the arbor--shrub configuration. The effect of arbor on reducing PM10 concentration was weak and the effect of shrub on that was the weakest. Under the same condition of green configurations, the smaller the street's aspect ratio (the wider the street) was, the greater decrease in the concentration of PM10, which indicated that the wider street was favorable for ventilation and had the lower the concentration of pollutants and vice versa. Comparing the measured data with the numerical simulation data, the coefficient between the measured value and the simulated value was 0.9894, and the correlation between the simulated results and the field observation results was pretty high, so it could be proved that the convection-diffusion model that ENVI-met used was available for simulating the diffusion of atmosphere particulate matter and can give reasonable calculation results of the law of the diffusion of atmosphere particles.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:32
Main heading:Particles (particulate matter)
Controlled terms:Air quality - Aspect ratio - Computer software - Diffusion - Diffusion in liquids - Gases - Highway planning - Models - Numerical models - Remote sensing - Roads and streets - Vegetation - Wind
Uncontrolled terms:Atmospheric particulate - Convection-diffusion models - ENVI-met - High resolution remote sensing images - Meteorological factors - PM10 - Road greening layout - Urban road greenings
Classification code:406.2 Roads and Streets - 432.1 Highway Transportation, General - 443.1 Atmospheric Properties - 451.2 Air Pollution Control - 723 Computer Software, Data Handling and Applications - 921 Mathematics - 951 Materials Science
Numerical data indexing:Size 1.50e+00m
DOI:10.11975/j.issn.1002-6819.2018.20.029
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 16>
Accession number:20190206357018
Title:Design and experiment of integrated automatic transplanting mechanism for taking and planting of flower plug seedlings
Authors:Zhou, Meifang (1); Xu, Jianjun (1); Tong, Junhua (2); Yu, Gaohong (2); Zhao, Xiong (2); Xie, Jie (2)
Author affiliation:(1) Jinhua College of Profession and Technology, Jinhua; 321017, China; (2) Provincial Key Laboratory of Plant Machinery, Zhejiang Sci-Tech University, Hangzhou; 310018, China
Corresponding author:Yu, Gaohong(yugh@zstu.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:44-51
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In order to develop a more efficient and universal flower auto-transplantation technique, an auto-transplantation mechanism with the integrated function of seedling pick-up and transplanting has been designed. This mechanism involves gear driving and two transplanting arms of the same structure. The gear driving system is made up of one semi-circle gear, four oval planet gears and concave-convex lock-up arc. It aims to move with the non uniform speed through the operation of planet gears and pulling and imbedding of concave-convex lock-up arc. The auto-transplantation arm includes the transplanting claw, convex gear and removing gear-gap parts. It transfers the whirling operation of planet gear into straight-line operation of pick-up seedling. The manual finger scratching and planting were simulated by two pins at the end of the seedling arm. The auto-transplantation mechanism combines the pick-up and planting. The transplanting trajectory and the location of pick-up and planting were special. Thus, it is essential to design new mechanism accordance with the movement of pick-up clip and achieve "Double beak sharp" trajectory. In this paper, we designed a device of bouncing clip to lengthen the trajectory to realize the function of pick-up and planting, and it could facilitate the integration of the planting. At the same time, when the claw moves nearly to the pot seedling, the seedling needle was inserted into the soil with a certain angle of inclination, which could effectively avoid the injury of the seedlings and the interference with the seedling box. Based on the kinematics characteristics of the mechanism, a corresponding mathematic model was established, and the Visual Basic 6.0 software was used to optimize the mechanism parameters. The program was used to analyze the influence of the parameters of mechanism on the trajectory and attitude of the "Double beak sharp". Finally, the best group of mechanism parameters was selected, and then the 3D design and components assembly were carried out based on SolidWorks 2015 software. Importing the 3D model to Adams, the trajectories of seedling needle could be obtained by the kinematics simulation. Finally, the prototype test was carried out and the test trajectory of the prototype was obtained by the test platform. Through the platform, the operation process was recorded by high-speed camera. Therefore, the trajectories of seedling needle could be tracked through the Bestcam picture analysis software. The results were basically the same among the simulation trajectory, the test trajectory of the prototype and the theoretical trajectory, which verified the correctness and feasibility of the design in this paper. Experimental research was carried out using the prototype, "Marigold chrysanthemum" seedlings were selected in the experiment, the basic composition of the pot seedling combines the pearl cave and peat mud, with the water component of 46%, the seedling tray were eight lines and 16 rows, both the length and width of seedling were 31 mm, and depth was 43 mm, and the test seedlings of marigold were 35 days, with the average height of 10 cm. The rotation speed of the mechanism was set as 35 r/min, its mean efficiency was 70 stems per minute. The obtained seedling success rate was 97.27%, while the transplanting success rate was 77.62%. It reflected the practicality of the integrated transplanting mechanism; the research could provide a reference for the key technology of automatic transplanting.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:30
Main heading:Seed
Controlled terms:Agricultural machinery - Combines - Design - High speed cameras - Integration - Kinematics - Locks (fasteners) - Machine design - Needles - Pickups - Testing - Trajectories - Transplants - Visual BASIC
Uncontrolled terms:Experimental research - Flowers - Integrated function - Kinematics characteristics - Kinematics simulation - Mechanism-parameters - Theoretical trajectory - Transplanting mechanisms
Classification code:462.4 Prosthetics - 601 Mechanical Design - 723.1.1 Computer Programming Languages - 742.2 Photographic Equipment - 821.1 Agricultural Machinery and Equipment - 821.4 Agricultural Products - 921.2 Calculus - 931.1 Mechanics
Numerical data indexing:Age 9.59e-02yr, Percentage 4.60e+01%, Percentage 7.76e+01%, Percentage 9.73e+01%, Rotational_Speed 3.50e+01RPM, Size 1.00e-01m, Size 3.10e-02m, Size 4.30e-02m
DOI:10.11975/j.issn.1002-6819.2018.20.006
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 17>
Accession number:20190206357039
Title:Continuous anaerobic treatment of swine wastewater by using self-agitation anaerobic baffled reactor
Authors:Qiao, Wei (1, 2); Ren, Zhengran (1, 2); Li, Chenyan (1, 2); Xiong, Linpeng (1, 2); Li, Yuyou (3); Dong, Renjie (1, 2, 4)
Author affiliation:(1) College of Engineering, China Agricultural University, Beijing; 100083, China; (2) R&D Center for Efficient Production and Comprehensive Utilization of Biobased Gaseous Fuels, Energy Authority, National Development and Reform Committee (BGFeuls), Beijing; 100083, China; (3) Department of Civil and Environmental Engineering, Tohoku University, Sendai; 980-8579, Japan; (4) Institute of Yantai, China Agricultural University, Yantai; 264670, China
Corresponding author:Dong, Renjie(rjdong@cau.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:210-215
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:With the development of pig industry in China, environmental pollution from such development has become more and more serious. One of the most important problems of pig breeding is the wastewater treatment. Swine wastewater is characterized by the high concentrations of organic matters. Anaerobic digestion has been regarded as a promising technology for swine wastewater treatment to remove the high-concentration organic materials. At the same time, renewable energy in the form of biogas was produced through anaerobic degradation. Previous studies have reported that anaerobic baffled reactor (ABR) can achieve good performance in treating swine wastewater. However, due to the absence of agitation system, the mass transfer is an ABR is unsatisfactory. In order to improve the performance of an ABR, the self-agitation anaerobic baffled reactor (SaABR) was proposed. In the SaABR, a U tube was assembled inside the reactor. SaABR is previously studied in the anaerobic treatment. However, fewer its application in treating swine wastewater was found. The current study therefore investigated the performance of a long term operated SaABR in treating swine wastewater. The total and working volume of SaABR in this study were 16 and 10 L, respectively. Anaerobic treatment of swine wastewater for a period of 200-day was continuously conducted. Mesophilic condition was maintained at 37℃ while hydraulic retention time (HRT) was gradual shortening from 5, 3, 2, 1, to 0.5 days. The effects of HRT on the biomass retaining, biogas gas production, process stability, and specific methanogenic activity (SMA) was investigated. At the same time, in this study, we also conducted a 78-day continuous experiment by using a parallel continuous stirred tank reactor (CSTR) as control test. The results derived from this study indicated that SaABR significantly retained high biomass concentration. At the HRT 3 d period, the volatile solid (VS) concentration of the first to fourth sampling ports of SaABR was 10.2, 4.1, 44.2 and 2.5 g/L, respectively. The concentration of VS in the CSTR was as low as 2.6 g/L. The higher microbial biomass significantly increased the degradation efficiencies of organic and reduced the VFAs concentration of SaABR effluent. The degradation efficiency of SaABR also decreased with the shortening of HRT. The specific methane yield of the SaABR was 0.43 L/g at the HRT 1 d period. At the HRT 0.5d period stable biogas production can still be achieved. Through the long term experiment, an increase of volumetric gas production rate was observed: 0.85, 1.14, 1.62 and 1.71 L/(L•d) at HRTs 3, 2, 1 and 0.5 days, respectively. Specific methane gas yield decreased from 0.69 to 0.24 L/g when HRT was reduced from 3 to 0.5 d. These values were slightly higher than results of a previous study using ABR treating swine manure at 40℃, which reported specific methane yield was 0.59 L/g. The CSTR ceased to produce biogas at HRT 1 d due to the washout of biomass. At HRT 3 d period, the sludge SMA from the first to the fourth sampling port were 116, 97, 44 and 85 mL/(g•d), respectively. Conclusively, the results obtained in this study showed that SaABR had the advantages of retaining high biomass and would be a promising technology for the anaerobic treatment of swine wastewater.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:29
Main heading:Anaerobic digestion
Controlled terms:Biogas - Biomass - Degradation - Effluents - Fermentation - Fertilizers - Mammals - Mass transfer - Methane - Wastewater - Wastewater treatment
Uncontrolled terms:Anaerobic baffled reactor - Biomass concentrations - Continuous stirred tank reactor - Degradation efficiency - Environmental pollutions - Hydraulic retention time - Self-agitation - Specific methanogenic activity
Classification code:452.3 Industrial Wastes - 452.4 Industrial Wastes Treatment and Disposal - 522 Gas Fuels - 641.3 Mass Transfer - 802.2 Chemical Reactions - 804 Chemical Products Generally - 804.1 Organic Compounds
Numerical data indexing:Age 1.37e-03yr, Age 2.14e-01yr, Age 2.74e-03yr, Age 5.48e-01yr, Mass_Density 2.50e+00kg/m3, Mass_Density 2.60e+00kg/m3, Mass_Density 4.42e+01kg/m3, Specific_Volume 4.30e-01m3/kg, Specific_Volume 5.90e-01m3/kg, Specific_Volume 6.90e-01m3/kg to 2.40e-01m3/kg, Volume 1.00e-02m3, Volume 1.60e-02m3
DOI:10.11975/j.issn.1002-6819.2018.20.027
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 18>
Accession number:20190206357019
Title:Simulation of flow induced noise in process of pump-turbine load rejection
Authors:Mao, Xiuli (1); Sun, Aoran (2); Pavesi, Giorgio (3); Zheng, Yuan (4); Ge, Xinfeng (4)
Author affiliation:(1) Institute of Water Resources and Hydropower Research, Northwest A&F University, Yangling; 712100, China; (2) Anhui Survey and Design Institute of Water Conservancy and Hydropower, Hefei; 230088, China; (3) Department of Industrial Engineering, University of Padua, Padua; 35131, Italy; (4) College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing; 210000, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:52-58
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The grid market is redistributed with significantly increase of the exploitation of unpredictable renewable energy, such as wind and solar energy sources, however, the ways of electricity generation by both wind and solar energy depend on environment which is extremely unstable. For the sake of balancing electricity generated by renewable energy, pumped storage power stations are experiencing a thriving process. As the core of pumped storage power station, the stable operation of the pump turbine is extremely important, especially for pump-turbine working at transient conditions. In order to study pressure fluctuating characteristics and its' influence on flow-induced noise, a continuous unsteady simulation was carried out in pump-turbine guide vane closing process under generating mode. In this article, wall sliding mesh was used to realize guide vane continuous motion, which ensured that the mesh quality at any moment was larger than 60% compared with the initial mesh quality, meanwhile, DES turbulent model was adopted in all calculations due to its good performance in many industrial cases. The whole pump-turbine model was meshed with structured mesh by commercial software ICEM, and five different mesh sizes were used in mesh sensitivity validation, with the size of 14 million selected finally. On the other hand, a test was performed by the team of Giorgio Pavesi to prove this model in open test facility in Padova University, the entire model validation was carried out according to ISO standards, and relative parameters were measured based on IEC standards. Commercial software ANYSYS CFX 16.2 was used to realize all simulating calculations with 8 computer cores, one month was taken to finish this calculation. The flow field calculating results were analyzed in frequency and time-frequency domains, including mass flow, pressure, and torque et al., in the meantime, the pressure on the surfaces of blades was regarded as flow-induced noise source to study sound field. The solution obtained from flow field illustrates that pressure fluctuating amplitudes at guide vane outlet is more than twice compared to the relative value at guide vane inlet location, the main reason is flow in the vaneless space that is close to runner is affected by rotor-rotor interaction. In addition, pressure pulsations at runner outlet arrive at peaks when two vortexes appear in draft tube with two different rotating directions. As for frequency domain characteristics, both strauhal number St=0.051 and St=1 are captured, whereas the spectrum of those pressure fluctuations that are close to guide vane outlet is 10 times of the relative value at guide vane inlet, which explains that rotor-rotor interaction has a stronger influence on flow field than rotor-stator interaction. Some rules are found by analyzing flow-induced noise in sound field, the analysis illustrates that flow-induced noise radiation level is related to both pressure fluctuating and shell natural frequency captured in exterior acoustic field, the shape of sound distribution is like "∞" and sound level distributions in different directions and faces are symmetrical, this explains that the blade noise radiation has obvious dipole characteristics. Furthermore, at the first and second-order blade passage frequencies, the effect of flow rate on the radiation performance of noise is stronger under larger flow conditions during guide vane closure, which becomes weaker under smaller flow conditions in the first half of the guide vane closure, as for the second half phase of guide vane closure, the results are exactly opposite to the previous phenomena. Moreover, flow-induced noise radiation is consistent with fluid characteristics during pump-turbine load rejection. Consequently, to improve pressure fluctuating characteristics can reduce flow-induced noise.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:27
Main heading:Hydraulic turbines
Controlled terms:Acoustic field measurement - Acoustic fields - Acoustic noise - Electric power generation - Flow fields - Frequency domain analysis - Impellers - ISO Standards - Mesh generation - Plant shutdowns - Pressure - Pumped storage power plants - Pumps - Rotors - Solar energy
Uncontrolled terms:Blade passage frequency - Electricity generation - Load rejections - Noises - Pump-turbines - Pumped storage power station - Rotor-stator interactions - Time frequency domain
Classification code:601.2 Machine Components - 611.1 Hydroelectric Power Plants - 617.1 Hydraulic Turbines - 618.2 Pumps - 631.1 Fluid Flow, General - 657.1 Solar Energy and Phenomena - 751 Acoustics, Noise. Sound - 921.3 Mathematical Transformations - 921.4 Combinatorial Mathematics, Includes Graph Theory, Set Theory - 931.1 Mechanics
Numerical data indexing:Percentage 6.00e+01%
DOI:10.11975/j.issn.1002-6819.2018.20.007
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 19>
Accession number:20190206357050
Title:Analysis on influence of rotor lead and eccentricity on mixing flow field and efficiency of dough mixer
Authors:Zhu, Xiangzhe (1); Gao, He (1); Liu, Jian (1)
Author affiliation:(1) School of Mechanical Engineering, Liaoning Shihua University, Fushun; 113001, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:305-314
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The chaotic food mixer with an eccentric spiral rotor is a new type of food processing device, in which the food fluids with long molecular chains can not be damaged by high shear stresses, such as traditional twin screw extruders. In fact, the previous researches had demonstrated that the food melt with high viscosity flowing in the food mixer has the nature of chaotic mixing. However, as a dynamic system of flow, the traditional Euler methods is difficult to distinguish the chaotic manifolds, which is a barrier for better understanding the mixing mechanism in the internal mixer. From a new viewpoint of 3D Lagrangian, the objective of our study is to explore the chaotic mixing mechanism in this new kind of food mixer under the disturbance of eccentric spiral rotor, to visually locate the poor and well mixing regions in the mixer and optimize the key geometric parameters of the eccentric spiral rotors. Firstly, a numerical simulation of the three-dimensional flow field in the food mixer is carried out using the mesh superposition technique (MST) and CFD code of Polyflow without considering the re-meshing for the periodical geometric changes. The Carreau-Yasuda constitutive model was used to describe the rheological behavior of the food material. Based on the transient velocity distributions, the finite time Lyapunov exponent (FTLE), Lagrangian coherent structure (LCS) and Poincaré section were calculated to analyze the fluid transport and mixing in the new chaotic food mixer with helical eccentric rotors. The LCS from the ridges of FTLE as a boundary was adopted to reveal the chaotic and regular zones in the mixer. And the particle tracking was used to illustrate the different fluid motions in the flow dynamic system based on the fourth-order Runge-Kutta scheme. Then the effects of rotor eccentric ratio on the chaos scale and particles motions in the regular of the mixer were studied, respectively. Moreover, based on the quantitative mixing measures, such as mixing shear rate, logarithmic of stretching, instantaneous mixing efficiency and average time mixing efficiency, the rotor lead and eccentricity rate were optimized to increase the mixing inefficiency of the chaotic food mixer. The results show that the hyperbolic LCSs divide into two regions with different particle motion characteristics for the food mixer, such as the inner rotary zone and the outer spiral zone. With the increase of rotor eccentric ratio, the strength of chaotic mixing in the outer spiral zone increases and that in the inner rotary zone decreases. When the rotor has little eccentric ratio, the mixing mainly depends on the fluid transport in the inner rotary zone. Then the axial velocity of fluid decreases significantly, but the mixing at radial direction of the inner rotary zone increases. Through optimization of the eccentricity and the lead distance of the eccentric rotor, it can be found that the mixer has relatively higher overall mixing efficiency with the lead of 120 mm and the eccentricity of 0.67, following is the lead of 60 mm and the eccentricity of 0.97, and the mixer has relatively poorer overall mixing efficiency with the lead of 60 mm and the eccentricity of 0.33. This paper has shown that the Lagrangian fresh perspective is more feasible than traditional Euler method in numerically investigate the evolution of two-dimensional mixing performance within a novel mixer. FTLE and LCS are useful tools for analyzing chaotic mixing flow in the mixer. This method provides new research ideas and theoretical basis for the design and optimization of food and other mixed equipment, which provides a better understanding the mixing mechanisms in a flow dynamic system.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:30
Main heading:Chemical contamination
Controlled terms:Computational fluid dynamics - Efficiency - Flow fields - Food processing - Lagrange multipliers - Lyapunov methods - Mixers (machinery) - Mixing - Polyethylenes - Processed foods - Runge Kutta methods - Shear stress - Transport properties
Uncontrolled terms:Design and optimization - Eccentric rotors - Finite-time Lyapunov exponent - Fourth-order runge-kutta - FTLE - Lagrangian coherent structures - Mesh superposition techniques - Three dimensional flow field
Classification code:631.1 Fluid Flow, General - 802.3 Chemical Operations - 815.1.1 Organic Polymers - 822.2 Food Processing Operations - 822.3 Food Products - 913.1 Production Engineering - 921.6 Numerical Methods - 931.1 Mechanics - 931.2 Physical Properties of Gases, Liquids and Solids - 961 Systems Science
Numerical data indexing:Size 1.20e-01m, Size 6.00e-02m
DOI:10.11975/j.issn.1002-6819.2018.20.038
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 20>
Accession number:20190206357023
Title:Effects of micro-sprinkler irrigation combined with drip irrigation on greenhouse high temperature environment and crop growth physiological characteristics
Authors:Zhang, Chuan (1); Zhang, Hengnian (1); Yan, Haofang (2); Acquah, Samuel Joe (2); Xing, Deke (1)
Author affiliation:(1) Institute of Agricultural Engineering, Jiangsu University, Zhenjiang; 212013, China; (2) Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang; 212013, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:83-89
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Micro-sprinkler irrigation combined with drip irrigation(MSDI) refers to the use of crop canopy micro-sprinkler irrigation to improve crop growth environment on the basis of drip irrigation. The differences in greenhouse high temperature environment and crop growth physiological characteristics under two kinds of irrigation modes, MSDI and surface drip irrigation (SDI), were compared and analysed. The field observations of greenhouse high temperature environment and growth physiological characteristics of cucumber under two irrigation modes were conducted in a Venlo-type glass greenhouse in Jiangsu China from February to June 2017. The results show that greenhouse environmental variables like temperature and humidity of the canopy at different heights (0.8, 1.3 and 1.8 m) during night hours (18:00-06:00) are basically the same. However, with the increase of solar radiation during the daytime hours, the air temperature rises whereas the relative humidity falls. The pattern of fluctuation is as follows: The highest air temperature and the lowest relative humidity all occur at 1.8 m level; the highest relative humidity and the lowest air temperature also occur at 0.8 m level; and the air temperature and relative humidity levels at height 1.3 m appeared to be intermediate between that of the 0.8 and 1.8 m. The application of MSDI can increase the relative humidity of the greenhouse, reduce the air temperature and the leaf temperature to about 4℃. In terms of crop growth physiology characteristics, MSDI can increase plant height and stem diameterand promote cucumber plant growth. Correlation analysis results showed that the sap flow rate of cucumber plant was significantly positively correlated with air temperature, solar radiation and net radiation (P<0.01), and significantly negatively correlated with relative humidity (P<0.01). Applying MSDI can reduce the sap flow rate by decreasing the air temperature and increasing the relative humidity. The maximum photosynthetic efficiencies of cucumber under the two irrigation modes were almost the same, with the values of 0.74 (MSDI) and 0.77 (SDI), respectively. However, the daily average photosynthetic efficiencies were significantly different between the two irrigation modes, with the values of 0.57 and 0.47, respectively. This phenomenon indicates that the use of MSDI irrigation method can alleviate the stress of greenhouse high temperature on the actual light energy conversion efficiency of the PSII and improve the photosynthetic capacity of mesophyll cells. Under the two irrigation methods (MSDI and SDI), the stomatal conductance of cucumber leaves increased initially, and then decreased rapidly to a minimum. The photosynthetic rate behaved similarly, but slightly lagged behind the stomatal conductance. The effect of MSDI irrigation on the stomatal conductance and photosynthetic rate of greenhouse cucumber leaves was obvious during the study. The average daily stomatal conductance and photosynthetic rate of cucumber leaves under MSDI mode were higher than SDI mode with 182.8% and 92.4%, respectively. The results have significant importance in reasonable regulation of greenhouse high temperature environment, and in improving greenhouse crop yield.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:37
Main heading:Sprinkler systems (irrigation)
Controlled terms:Atmospheric temperature - Conversion efficiency - Crops - Energy conversion - Greenhouse effect - Greenhouses - Irrigation - Physiology - Plants (botany) - Solar radiation
Uncontrolled terms:Photosynthetic efficiency - Photosynthetic rate - Sap flow - Sprinkler irrigation - Surface drip irrigations
Classification code:443.1 Atmospheric Properties - 461.9 Biology - 525.5 Energy Conversion Issues - 657.1 Solar Energy and Phenomena - 821 Agricultural Equipment and Methods; Vegetation and Pest Control
Numerical data indexing:Percentage 1.83e+02%, Percentage 9.24e+01%, Size 1.30e+00m, Size 1.80e+00m, Size 8.00e-01m
DOI:10.11975/j.issn.1002-6819.2018.20.011
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 21>
Accession number:20190206357046
Title:Optimization of land use spatial pattern in Jiangchuan district based on ecological sensitivity analysis
Authors:Li, Yimin (1, 2, 3); Guan, Chengwen (1, 2, 3); Guo, Liqin (1, 4); Zhu, Jun (1, 2, 3); Duan, Yaping (1, 2, 3); Xie, Yaya (1, 2, 3)
Author affiliation:(1) College of Resource Environment and Earth Science, Yunnan University, Kunming; 650500, China; (2) Yunnan Institute of Geography, Kunming; 650034, China; (3) Key Laboratory of Pollution Process and Management of Lake Basin in Yunnan Province, Kunming; 650034, China; (4) Yunnan Provincial Mapping Institute, Kunming; 650034, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:267-276
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In order to optimize the spatial pattern of land use and promote the sustainable development of the land, taking the Jiangchuan District of Yuxi City, Yunnan Province as the research area, in this paper, we adopted the CLUE-S (The Conversion of Land Use and its effects at Small Region Extent) and ecological sensitivity analysis methods that were applied to the optimal allocation of land use spatial pattern in Jiangchuan District. We took the highly sensitive region as the regional constraint document in the CLUE-S model to highlight the key areas of ecological protection in the studied area. Based on the comprehensive ecological sensitivity zoning as the driving force factor affecting the land use change in the study area, a land use scenario simulation method was proposed in which the ecological sensitivity was integrated into the land use spatial pattern optimization configuration process and results. With the use of land use data in 2006 and 2016, the land use spatial pattern of 2025 in the two modes of natural development scenarios and land ecological optimization scenarios in Jiangchuan District would be optimized. The simulation results of optimized configuration were analyzed and validated based on ecological sensitivity partition. The results showed that by selecting five secondary indicators of soil erosion intensity, land use type, vegetation coverage, distance from water source and disaster susceptibility, we constructed a watershed ecological sensitivity evaluation index system. Jiangchuan District's ecological sensitivity was mainly moderate or above sensitivity, and the area was 57 111.37 hm<sup>2</sup>, accounting for 70.91% of the total area of Jiangchuan District. According to the results of ecological sensitivity assessment, Jiangchuan District was divided into highly sensitive, moderately sensitive, mildly sensitive and non-sensitive, and it was divided into ecological protection core area, control development area and suitable development area. In addition, based on the 2006 land use data, and use of the CLUE-S model, the spatial pattern of land use in Jiangchuan District in 2016 was simulated. Compared with the land use data in 2016, the correct raster number of the simulation results accounted for 81.59% of the total number of grids. The Kappa coefficient was 0.779 1, and the CLUE-S model can be used to simulate the spatial pattern of land use in Jiangchuan District in 2025. Moreover, in the two scenarios, the land use pattern of Jiangchuan District in 2025 had both common features and differences. In the two scenarios, the original forest land, farmland, unused land and urban and residential land pattern were effectively protected, but the spatial distribution patterns of newly added forest land and grassland were different. The results of the optimal allocation of land use spatial pattern in Jiangchuan District in 2025 were verified. According to the distribution of major land use types in different sensitive areas in 2025 and the land use status in 2016, the spatial pattern of land use in Scenario 2 was better than natural development scenarios and the status of land use in 2016. The research results showed that the land ecological optimization scenario was more reasonable, which not only could reduce the area of cultivated land, but also consider the needs of ecological protection and urban development.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:25
Main heading:Land use
Controlled terms:Ecology - Forestry - Models - Sensitivity analysis - Spatial distribution - Urban growth
Uncontrolled terms:Ecological optimization - Ecological sensitivity - Ecological sensitivity analysis - Jiangchuan District - Optimal allocation - Optimized configuration - Spatial distribution patterns - Spatial patterns
Classification code:403 Urban and Regional Planning and Development - 403.1 Urban Planning and Development - 454.3 Ecology and Ecosystems - 921 Mathematics
Numerical data indexing:Percentage 7.09e+01%, Percentage 8.16e+01%
DOI:10.11975/j.issn.1002-6819.2018.20.034
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 22>
Accession number:20190206357027
Title:Farmland soil moisture retrieval using PROSAIL and water cloud model
Authors:Cai, Qingkong (1); Li, Erjun (2); Tao, Liangliang (3); Jiang, Ruibo (1)
Author affiliation:(1) College of Civil Engineering, Henan Institute of Engineering, Zhengzhou; 451191, China; (2) College of Human and Social Sciences, Henan University of Engineering, Zhengzhou; 451191, China; (3) School of Geographical Sciences, Nanjing University of Information Science & Technology, Nanjing; 210044, China
Corresponding author:Li, Erjun(hnwxlej@163.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:117-123
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Soil moisture, as an important component of soil, plays an important role in the process of energy exchange between soil surface and atmosphere. It is an important input parameter of hydrological, ecological and other physical models. Real-time and dynamic monitoring of soil moisture has a very important significance to agricultural production and crop yield estimation. Nowadays, optical and radar remote sensing are the 2 potential methods for quantifying soil moisture monitoring. However, optical remote sensing, vulnerable to the weather, cannot penetrate clouds and vegetation, which has great limitations in practical applications. Radar remote sensing is sensitive to the dielectric constant of soil and becomes one of the popular soil moisture acquisition methods. Obtaining surface soil moisture by using radar remote sensing is often affected by surface roughness. In areas covered with vegetation, it is also affected by vegetation layers. Many effective inversion models were proposed and the most commonly used model is water-cloud model. It, as a semi-empirical method for herbaceous vegetation, is often used for the retrieval of water content and biomass of vegetation and soil moisture. In the model, vegetation canopy is often regarded as a homogenous scatterer and volumetric scattering is the main form of herbaceous vegetation. However, in the natural condition, the distribution of herbaceous vegetation is not uniform, and especially in the case of complex land cover, the water-cloud model will be greatly limited in sparse vegetation covered area. Therefore, this paper presents a semi-empirical coupling algorithm combining water-cloud model and PROSAIL optical model. This algorithm introduces vegetation coverage to separate the crop scattering contribution from the surface direct scattering contribution of bare soil. Meanwhile, the actual distribution of vegetation is fully considered, especially for the sparse vegetation covered area. The coupling algorithm can eliminate the influence of crop canopy on radar signals to the maximum extent and establish a more accurate relationship between the surface direct backscatter contribution and soil moisture to obtain the soil moisture inversion value with a higher accuracy. The experimental results show that the inversion accuracy of the semi-empirical coupling algorithm can meet the demand of simulating the backscattering coefficients compared with the observations. In HH and VV polarizations, R<sup>2</sup> values are 0.792 and 0.723, and RMSE (root mean square error) values are 0.600 and 0.837 dB, respectively. The coupling model introduces vegetation coverage to reduce the effect of vegetation gap on radar signals and characterize accurately the direct scattering contribution of bare soil. Meanwhile, the estimation accuracy of the semi-empirical coupling algorithm proposed in this paper is higher than that obtained by using the original water-cloud model, with R<sup>2</sup> of 0.809 and RMSE of 0.043 cm<sup>3</sup>/cm<sup>3</sup>. Therefore, this algorithm has a high sensitivity to the vegetation ranging from relatively sparse to full cover and can eliminate the influence of vegetation canopy on radar backscatter coefficient by applying the optical data information to the inversion of soil moisture in the coupling model. It will provide ideas and theoretical support for soil moisture inversion in large area and complex land surface coverage. Because of limited experiment condition, errors of field measurement remain in backscattering simulation and soil moisture retrieval. Field experiments need to be conducted in complex and multi-vegetation cover areas to obtain enough measurements and further improve the coupling model.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:42
Main heading:Soil surveys
Controlled terms:Backscattering - Cloud computing - Crops - Mean square error - Moisture control - Radar - Remote sensing - Soil moisture - Surface roughness - Vegetation - Water content
Uncontrolled terms:Backscatter coefficients - Coupling modeling - Leaf Area Index - Vegetation coverage - Water cloud models
Classification code:483.1 Soils and Soil Mechanics - 716.2 Radar Systems and Equipment - 722.4 Digital Computers and Systems - 731.3 Specific Variables Control - 821.4 Agricultural Products - 922.2 Mathematical Statistics - 931.2 Physical Properties of Gases, Liquids and Solids
Numerical data indexing:Decibel 6.00e-01dB, Decibel 8.37e-01dB
DOI:10.11975/j.issn.1002-6819.2018.20.015
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 23>
Accession number:20190206357036
Title:Analysis of influencing factors of solar thermoelectric power generation module efficiency based on micro heat pipe array
Authors:Wang, Lishu (1); Yang, Mengcheng (1); Li, Ying (1); Zhang, Xu (1); Ren, Jiaju (1); Bao, Mingxuan (1)
Author affiliation:(1) Institute of Electrical and Information, Northeast Agricultural University, Harbin; 150030, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:189-196
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In order to improve the conversion efficiency of low-temperature utilization in solar energy resources, the micro heat pipe was used in solar thermal power generation to make a solar thermal power generation component, and the factors influencing the light-heat conversion efficiency and the thermoelectric efficiency of the component were analyzed in this article. At present, in the utilization of solar energy resources, this article mainly focused on the characteristics of strong dispersion of solar radiation and low energy density. The micro-thermal-tube-based solar thermal power generation device proposed in this article is a solar energy medium-low temperature utilization device. Solar low-temperature power generation technology can effectively compensate for the shortage of solar high-temperature thermal power generation. Medium-low temperature power generation technology can effectively utilize the characteristics of strong solar radiation dispersion and low energy flow density. And solar low temperature power generation technology can effectively avoid the limitations of high temperature power generation, such as the use of large areas of high temperature areas, high focus ratio, complexity of tracking method and control methods, high operating costs of installation and maintenance, technical difficulties and so on. The solar thermal power generation using the micro heat pipe array fully utilizes the strong dispersion characteristics of the solar radiation, expands the contact area, increases the heat absorption efficiency, and adopts heat preservation treatment to realize heat storage, radiation reduction, and convection with the environment. This module does not only have the characteristics of flat panel solar collectors, such as easy integration with buildings and simple tracking methods, but also has strong frost resistance and stable operation. This article conducted experimental research and simulation analysis on the factors influencing solar thermal differential power generation efficiency of micro heat pipe arrays and discussed the effects of factors such as solar radiation, ambient temperature, thermoelectric unit logarithm, and series-parallel connection mode on the efficiency of the components and made a major difference in temperature difference power generation technology. Scale application provided reference. When the temperature difference was 30℃, different logarithm thermoelectric units had almost no effect on conversion efficiency; the greater the temperature difference was, the greater the effect of thermoelectric logarithm on conversion efficiency would be. 127 pairs of thermoelectric units, when the temperature difference was 270℃, increased to 6.53%, the conversion efficiency was 4.12% higher than 1 pair of thermoelectric units. The same number of temperature difference power generation chips adopt different series-parallel connection mode, which also has a great influence on power generation efficiency; the load resistance is lower than 2 Ω, and the output power of four parallel circuits is the largest; when the load resistance is 1 Ω, the output power of four parallel circuits can reach 0.39 W; When the load resistance is between 2 and 15 Ω, the output power of the two series and the parallel is the largest; when the load resistance is 5 Ω, the latter one reaches 0.52 W; the load resistance is greater than 15 Ω, and the output power of the four components is the largest when connected in series.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:28
Main heading:Energy efficiency
Controlled terms:Capillary flow - Conversion efficiency - Dispersions - Electric connectors - Factor analysis - Heat pipes - Heat storage - Operating costs - Radiation effects - Solar energy - Solar heating - Solar radiation - Temperature - Thermal management (electronics) - Thermoelectric power
Uncontrolled terms:Generation - Micro heat pipe - Photothermal conversion efficiencies - Thermal logarithm - Thermoelectric conversion efficiency
Classification code:525.2 Energy Conservation - 525.5 Energy Conversion Issues - 619.1 Pipe, Piping and Pipelines - 631.1 Fluid Flow, General - 641.1 Thermodynamics - 657.1 Solar Energy and Phenomena - 704.1 Electric Components - 911.1 Cost Accounting - 922.2 Mathematical Statistics - 951 Materials Science
Numerical data indexing:Electrical_Resistance 1.00e+00Ohms, Electrical_Resistance 1.50e+01Ohms, Electrical_Resistance 2.00e+00Ohms to 1.50e+01Ohms, Electrical_Resistance 2.00e+00Ohms, Electrical_Resistance 5.00e+00Ohms, Percentage 4.12e+00%, Percentage 6.53e+00%
DOI:10.11975/j.issn.1002-6819.2018.20.024
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 24>
Accession number:20190206357026
Title:Crop yield and water consumption of different cropping patterns under different precipitation years in North China Plain
Authors:Zhao, Yanxi (1); Xiao, Dengpan (1); Qi, Yongqing (2); Bai, Huizi (1)
Author affiliation:(1) Institute of Geographical Sciences, Hebei Academy of Sciences, Hebei Engineering Research Center for Geographic Information Application, Shijiazhuang; 050011, China; (2) Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Key Laboratory of Agricultural Water Resources, Shijiazhuang; 050021, China
Corresponding author:Xiao, Dengpan(xiaodengpan168@163.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:108-116
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:North China Plain is the important grain production base in China, and the status in the national food industry is very high. However, long-term irrigation has caused heavy losses of groundwater resources in North China Plain, and then groundwater level continues to decline. Crop model can simulate crop growth in a variety of simulation scenarios based on the present research experiments, predict some unknown risks, optimize the management measures of agricultural resources and provide scientific guidance for management of agricultural production. APSIM (agricultural production system simulator model) model is just typical representative of crop model. Therefore, the study used APSIM model to simulate the yield and water consumption situation under different cropping patterns in North China Plain during 1986-2015, to provide scientific basis for adjusting crop planting pattern, agricultural water resource management and agricultural development policy formulation in North China Plain. The results showed that APSIM model could well simulate the winter wheat and summer maize growth period, yield and water use characteristics. The error of crop growth period simulation results was within 5 d, and the R<sup>2</sup> values of production, ET and drain simulation results were above 0.84. The results proved that the model had better applicability in North China Plain; the annual yield of wheat-maize double-cropping system (M2Y1) was 13 445 kg/hm<sup>2</sup>, followed by the yield of 11 076 kg/hm<sup>2</sup> for the two-year cropping pattern of winter wheat/summer maize/early maize (M3Y2), and the lowest yield per year was 9 215 kg/hm<sup>2</sup> for early maize one-year cropping pattern (M1Y1) with the decreasing trend of -2 000 kg/hm<sup>2</sup>. The trend of ET corresponding to yield was 724 mm (M2Y1) > 631 mm (M3Y2) > 534 mm (M1Y1), while the decreasing trend was -100 mm. The quantity of drain and overdraft of M2Y1, M3Y2 and M1Y1 all decreased, but the decreasing trend of drain was not significant while the decreasing trend of overdraft was similar to that of ET, which was -100 mm. Comparing yield and water consumption of 3 cropping patterns, we can know that the difference of water consumption in different cropping patterns was mainly related to the growth of winter wheat. The average annual water consumption of winter wheat was over 400 mm, while the average annual precipitation of wheat growth period was less than 140 mm and the overdraft exceeded 260 mm. The mismatch between precipitation and crop water demand leads to irrigation water increase, serious groundwater loss and lower groundwater level, which is not conducive to the sustainable utilization of groundwater resources in North China Plain. In conclusion, wheat-maize double-cropping system had not only the highest annual output, but high water consumption and the most serious water loss in North China Plain; two-year cropping pattern of winter wheat/summer maize/early maize gave consideration to yield and water consumption, and the comprehensive effect of yield and water consumption was the best. In addition, this study compared yield and water consumption of different cropping patterns under different precipitation years in Luancheng, Hebei, which proved that precipitation resources are of great significance to the growth of crops, while the yield was higher and the water loss was relatively small in the year of high precipitation.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:39
Main heading:Crops
Controlled terms:Groundwater - Groundwater resources - Irrigation - Models - Risk assessment - Risk perception - Water management - Water supply
Uncontrolled terms:Agricultural development - Agricultural production system - Agricultural productions - Annual water consumption - Average annual precipitation - Cropping patterns - North China Plain - Water consumption
Classification code:444.2 Groundwater - 446.1 Water Supply Systems - 821.3 Agricultural Methods - 821.4 Agricultural Products - 914.1 Accidents and Accident Prevention
Numerical data indexing:Size -1.00e-01m, Size 1.40e-01m, Size 2.60e-01m, Size 4.00e-01m
DOI:10.11975/j.issn.1002-6819.2018.20.014
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 25>
Accession number:20190206357013
Title:Review on boundary shift of farming-pastoral ecotone in northern China and its driving forces
Authors:Shi, Xiaoli (1, 3); Shi, Wenjiao (2, 4)
Author affiliation:(1) College of Resources and Environment Sciences, Hebei Normal University, Shijiazhuang; 050024, China; (2) Key Laboratory of Land Surface Pattern and Simulation of CAS, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing; 100101, China; (3) Key Laboratory of Environmental Evolvement and Ecological Construction of Hebei Province, Shijiazhuang; 050024, China; (4) College of Resources and Environment, University of Chinese Academy of Sciences, Beijing; 100049, China
Corresponding author:Shi, Wenjiao(shiwj@lreis.ac.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:1-11
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The boundary of agriculture-animal husbandry ecotone in northern China has changed frequently by climate change and human activities. Quantitatively detecting the contributions of climate change and human activities to the boundary changes of the farming-pastoral ecotone in northern China has been a hot topic in the field of climate change. In recent years, an increasing number of studies have documented the boundary changes in the farming-pastoral ecotone in northern China. However, for a long time, there was not a unified definition of the farming-pastoral ecotone in northern China. Based on the related literatures, we systematically reviewed the definitions of the farming-pastoral ecotone in northern China from five respects. 1) The definition based on the substitute evidences, according to the information indicated in the historical literatures, archaeological events, pollen records, ice cores and tree-rings, the historical boundary of the farming-pastoral ecotone in northern China can be delineated. 2) The definition based on the field investigations, is according to the scholars' field surveys of the farming-pastoral ecotone in northern China. 3) The definition based on the climatic factors, according to the range of the precipitation (such as the 400 mm isohyet), moisture, temperature and wind, the farming-pastoral ecotone in northern China can be draw accurately. 4) The definition based on the land use factors, according to the proportions of the grassland and cropland, the scope conforming to the farming-pastoral ecotone was selected. 5)The definition based on the comprehensive indicators, this method often combines the land use factors and climatic factors to define the scope of the farming-pastoral ecotone in northern China, besides this, the vegetation, the economic level and livelihood were also used to draw the outline of the farming-pastoral ecotone in northern China. Then we analyzed the contributions of the climate change and human activities to the boundary changes of the farming-pastoral ecotone in northern China. For the climate change, the boundary of the farming-pastoral ecotone in northern China changed northward during the warmer-wetter period and changed southward during the colder-drier period. For the human activities, the policies, increased population, developed economic levels, religion and diet structure were all the main driving forces of the boundary changes of the farming-pastoral ecotone in northern China. After that, we introduced the quantitative progresses of the previous researches on evaluation of the contributions of the climate change and human activities. However, there were four defects in assessing the contributions of climate change and human activities to boundary changes of the farming-pastoral ecotone in northern China, such as the lack of the comprehensive definition, the quantitative method, the systematical data and the reasonable explanation. Meanwhile, we obtained the solutions to the existing problems. For example, composited definition based on multi-factors, quantitative identification of driving forces at multi-scales, collection of high resolutions data and the detailed explanations of the mechanism of boundary change. Understanding the contributions of climate change and human activities to the farming-pastoral ecotone in northern China is essential for making comprehensive decisions concerning human adaptability to climate change in different regions; the study will be helpful to the management of reasonable land use and the mitigation and adaptation to climate change for the sensitive regions.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:70
Main heading:Climate change
Controlled terms:Agriculture - Chemical analysis - Land use
Uncontrolled terms:Adaptation to climate changes - Boundary shifts - Farming-pastoral ecotone - Field investigation - Human activities - Quantitative identification - Quantitative method - Sensitive regions
Classification code:403 Urban and Regional Planning and Development - 443.1 Atmospheric Properties - 821 Agricultural Equipment and Methods; Vegetation and Pest Control
Numerical data indexing:Size 4.00e-01m
DOI:10.11975/j.issn.1002-6819.2018.20.001
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 26>
Accession number:20190206357016
Title:Design and experiment of remote intelligent spray control system based on embedded internet
Authors:Wu, Yalei (1); Qi, Lijun (1); Zhang, Hao (1); Cheng, Zhenzhen (1); Liu, Wanwan (1); Xie, Desheng (2); Musiu, Elizabeth (1)
Author affiliation:(1) College of Engineering, China Agricultural University, Beijing; 100083, China; (2) Shenzhen Longrui Technology Company, Guangzhou; 518108, China
Corresponding author:Qi, Lijun(qilijun@cau.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:28-35
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In view of the current weak status of intelligent management and control systems for facility of agriculture and dwarfed orchards, high labor intensity and complicated spraying environment, this article proposed an embedded technology, which took STM32F101 and STM32F103 as the core and basis, combined with 4G Internet and ultrasonic target detection algorithm, and was able to remotely control agricultural machinery to achieve the purpose of human-machine separation and precise application of pesticides. The system used Socket and multi-thread technology to implement two-way communication under the Eclipse and Keil-uvision4 development environment. With TCP communication protocol as the medium, the Android and client transferred remote routing through the Internet or wireless network card to achieve remote intelligent spray control. The test results show that: 1) Android can implement near-remote control of smart spray equipment in the LAN or Internet. The software interface returns that no stagnant state or delay occurs and it can accurately transmit control commands and achieve intermittent application of the target. 2) The bidirectional heartbeat package established by the system can force the spray equipment to be dormant in the event of communication failure. After testing, the error rate of the heartbeat packet set-up time and the spray equipment dormancy response time does not exceed 5.50%. 3) Use the video frame to locate the canopy middle line, and use the ultrasonic detection algorithm to determine the wind-distance parameters and establish the canopy volume model. Through experiments, it is found that the degree of canopy denseness has a significant impact on the measured results of the canopy volume measurement system. The text measurement system should be used in dense canopy conditions, and the measurement accuracy is as high as 94.67%. 4) The remote smart spray control system in this article can realize local network and long-distance internet communication. Use "Ping" command to check the network response to IP data packets. There is no packet loss problem and the average response time is 5 and 79 ms, respectively. 5) The degree of canopy density has a significant effect on the measurement of the canopy volume measurement system. There is a significant difference between the manual and automatic measurements of the canopy volume in sparse conditions. On the contrary, there is no significant difference between the manual and automatic measurements of the canopy volume in the dense conditions, which is suitable for measuring the canopy volume in this article. In the system, the maximum relative error is only 6.4%, and the canopy coverage and distribution uniformity will be significantly improved. 6) A remote control and optimized application system available for complete Internet-based spray equipment is designed. The system can realize human-machine separation and precise application of pesticides. Through tests, it can be seen that the detection and processing of the fuselage faults has high reliability. At the same time, it has potential application value for the transformation of traditional production modes and the promotion of smart agricultural machinery. The study can also provide reference for the automation and intellectualization of other agricultural machinery equipment.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:34
Main heading:Internet protocols
Controlled terms:Agricultural machinery - Agriculture - Android (operating system) - Application programs - Control engineering - Control systems - Design - Embedded systems - Interface states - Packet networks - Pesticides - Remote control - Response time (computer systems) - Signal detection - Spraying - Titration - Ultrasonic testing - Volume measurement - Wireless networks
Uncontrolled terms:Development environment - Distribution uniformity - Embedded technology - Maximum relative errors - Multi-thread technology - Ultrasonic detection - Ultrasonic target detection - Wireless network communication
Classification code:716.1 Information Theory and Signal Processing - 716.3 Radio Systems and Equipment - 723 Computer Software, Data Handling and Applications - 731.1 Control Systems - 753.3 Ultrasonic Applications - 801 Chemistry - 803 Chemical Agents and Basic Industrial Chemicals - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 821.1 Agricultural Machinery and Equipment - 931 Classical Physics; Quantum Theory; Relativity - 932 High Energy Physics; Nuclear Physics; Plasma Physics - 943.2 Mechanical Variables Measurements
Numerical data indexing:Percentage 5.50e+00%, Percentage 6.40e+00%, Percentage 9.47e+01%, Time 5.00e-03s, Time 7.90e-02s
DOI:10.11975/j.issn.1002-6819.2018.20.004
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 27>
Accession number:20190206357029
Title:Estimation on GHG emission reduction in double cropping rice paddy with application of biochar in long-term period using LCA method
Authors:Zhang, Weihong (1, 2); Li, Yu'e (1); Qin, Xiaobo (1); Li, Jianling (1); Wan, Yunfan (1); Wang, Bin (1); Gao, Qingzhu (1); Liu, Shuo (1)
Author affiliation:(1) Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences/The Key Laboratory for Agro-Environment, Ministry of Agriculture, Beijing; 100081, China; (2) Hebei Sub-Center of CMATC, Baoding; 071000, China
Corresponding author:Li, Yu'e(liyue@caas.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:132-140
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Methane and N<inf>2</inf>O are two important greenhouse gases, which are the main emission in paddy ecology system. China is the highest rice planting country, so the greenhouse gas emission is huge in China. Application of biochar in paddy field can decrease the emissions of greenhouse gases. In this study, we investigated the greenhouse gas (GHG) emissions, carbon sequestration and economics of different rates of biochar application in a double rice cropping system. The experiment was carried out in rice variety area promotion experiment field in Huizhou of Guangdong from March 2012 to September 2015. Four treatments were designed as CK (famer traditional operation without biochar application), BC1 (biochar amendment at 5 t/hm<sup>2</sup>), BC2 (biochar amendment at 10 t/hm<sup>2</sup>), and BC3 (biochar amendment at 20 t/hm<sup>2</sup>), each treatment has 3 repeat. Biochar used in this study was obtained from wheat straw and produced by Henan Sanli New Energy Company. LCA (life cycle assessment) method was employed to calculate GHG emissions from the collection and transportation of raw materials, the production, transportation, and broadcasting of biochar, and from the avoidance of the straw burning and the soil carbon stocks. Static chamber-GC (gas chromatography) method was used to monitor the CH<inf>4</inf> and N<inf>2</inf>O emissions under different rates of biochar application from 2012 to 2015. Then, the net GHG emissions and the percentage of emission reduction in the paddy field with different biochar amendment rates were calculated. The total GHG emissions from the double rice cropping system were 19.5, 15.6, 16.1, and 12.4 t/hm<sup>2</sup> under CK, BC1, BC2, and BC3 treatments respectively in four years. Moreover, the total GHG emission reduction percentage of BC1, BC2 and BC3 were 19.70%, 17.46%, and 36.40%, respectively. Considering the GHG emissions of biochar in all stages of life cycle, the net GHG emissions of CK, BC1, BC2 and BC3 in the four years were 19.5, 20.3, 10.9, and 4.2 t/hm<sup>2</sup>, respectively, the treatment of BC1 increased the net emissions of 4.3% in the four years. BC2 and BC3 reduced the net GHG emissions by 44% and 78.6%, respectively in four years. The economic analysis indicated that the BC1treatment had more economic benefits compared to other treatments. The different biochar amendment rates significantly reduced the GHG emissions from the double rice cropping system, the highest application rate of biochar had the best emission reduction effect. The LCA of biochar application indicated that from medium to high application levels, biochar reduces emissions, for higher application rates of biochar, the effects are stronger. Moreover, the economic analysis indicated that the more amounts of biochar application, the least profitable to gain economic benefits.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:49
Main heading:Greenhouse gases
Controlled terms:Carbon footprint - Economic analysis - Economic and social effects - Emission control - Gas chromatography - Gas emissions - Life cycle - Materials handling
Uncontrolled terms:Application rates - Bio chars - Biochar amendments - Carbon sequestration - Economic benefits - Emission reduction - Life Cycle Assessment (LCA) - Rice cropping systems
Classification code:451.1 Air Pollution Sources - 451.2 Air Pollution Control - 454 Environmental Engineering - 802.3 Chemical Operations - 911.2 Industrial Economics - 971 Social Sciences
Numerical data indexing:Percentage 1.75e+01%, Percentage 1.97e+01%, Percentage 3.64e+01%, Percentage 4.30e+00%, Percentage 4.40e+01%, Percentage 7.86e+01%
DOI:10.11975/j.issn.1002-6819.2018.20.017
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 28>
Accession number:20190206357028
Title:Effects of mechanical compaction on soil microbial activities and carbon emission of oasis agricultural soils in Xinjiang
Authors:Li, Dianpeng (1); Wang, Hui (1); Sun, Tao (1); Liu, Suiyunhao (1); Li, Zheng (1); Zhang, Kai (1); Jia, Hongtao (1)
Author affiliation:(1) College of Grassland and Environment Sciences, Xinjiang Agricultural University, Urumqi; 830052, China
Corresponding author:Zhang, Kai(zhangkai4595241@163.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:124-131
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The impact of structural deformations on soil properties controls its function as habitat. Soil compaction is widespread but tends to be most prevalent where heavy machinery is used in forestry and agriculture. Untimely traffic with heavy logging machinery often leads to irreversible damage of soil structure, restricting plant growth, reducing crop yield or decreasing the greenhouse gas emissions mitigation potential from the farmland. Avoiding soil compaction caused by agricultural management is a key aim of sustainable land management; however, limited understanding exists on how compaction affects the soil carbon process and microbial activities. Thus, we conducted a 120-day laboratory incubation to evaluate the effects of soil compaction mainly in agricultural soils on soil organisms and soil biological processes to identify relevant parameters which are helpful for assessing soil compaction from the soil biological and environmental point of view. We evaluated if threshold values of soil bulk density correspond to impacts on soil microbial fertility and environmental effect on soil. Our literature review showed that bulk density of Xinjiang farmland soil ranges from 0.85-1.60 g/cm<sup>3</sup>. In this study we used i) non-compacted reference 1.15 g/cm<sup>3</sup> T<inf>1.15</inf>, ii) Treatment 1.30 g/cm<sup>3</sup> (T<inf>1.30</inf>), where soil was the median value of bulk density, iii) T<inf>1.45</inf>, with was 75% of the value, iv) T<inf>1.60</inf> was the maximum bulk density of the Xinjiang oasis farmland. In this study, we measured the soil carbon emission rate under different bulk density conditions using a Li-8100 automated soil CO<inf>2</inf> flux system (LI-COR, Lincoln,Nebraska,USA) from June to October 2016, and soil organic carbon (SOC), urease activity (URE), catalase activity (CAT), dissolved organic carbon (DOC), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) were also measured. The result showed that during the laboratory incubation time (0-120 d) treatment T<inf>1.15</inf>, T<inf>1.30</inf>, T<inf>1.45</inf> and T<inf>1.60</inf>, MBC, MBN, URE and CAT decreased with the extension of the test period. Under different bulk density levels, soil MBC, MBN, URE and CAT increased rapidly and then decreased with the increase of soil bulk density, and was the highest when the bulk density was 1.45 g/cm<sup>3</sup>. Cumulative carbon emission from T<inf>1.15</inf>, T<inf>1.30</inf>, T<inf>1.45</inf> and T<inf>1.60</inf> treatments was 557.26, 653.48, 665.00 and 522.01 g/m<sup>2</sup>, respectively. There was a trend of increasing first and then decreasing with increasing soil bulk density, and the highest was T<inf>1.45</inf>. The correlation analysis showed that soil carbon emissions were significantly correlated with urease and catalase activity (P<0.05), and very significantly correlated with soil organic carbon, dissolved organic carbon, and microbial biomass carbon and nitrogen (P<0.01). The effects of compaction on soil microbial activities and carbon emissions were weighed. Combined effects of trade-offs and compactions on soil biological activity and carbon emissions revealed that soil carbon emissions were the highest when the microbial activity is the highest, and therefore, the maximum microbial activities will also produce greater environmental effects. In summary, mechanical compaction directly affected microbial activities and carbon emissions by changing soil bulk density and pore structure. Therefore, when the soil capacity of oasis farmland was greater than or equal to or less than 1.45 g/cm<sup>3</sup>, proper overturning or repression should be carried out to make the soil biologically active at the best level.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:47
Main heading:Soil testing
Controlled terms:Bioactivity - Biomass - Compaction - Economic and social effects - Enzyme activity - Farms - Forestry - Gas emissions - Greenhouse gases - Lithium compounds - Machinery - Microorganisms - Nitrogen - Organic carbon - Soil conditioners - Soil mechanics - Soils - Stream flow
Uncontrolled terms:Carbon emissions - Mechanical compaction - Microbial biomass - Microbial biomass carbon and nitrogen - Soil biological activity - Soil microbial activities - Sustainable land managements - Xinjiang
Classification code:407.2 Waterways - 451.1 Air Pollution Sources - 461.6 Medicine and Pharmacology - 461.9 Biology - 483.1 Soils and Soil Mechanics - 804 Chemical Products Generally - 804.1 Organic Compounds - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 971 Social Sciences
Numerical data indexing:Age 3.29e-01yr, Mass_Density 1.45e+03kg/m3, Mass_Density 8.50e+02kg/m3 to 1.60e+03kg/m3, Percentage 7.50e+01%, Surface_Density 5.22e-01kg/m2, Surface_Density 6.65e-01kg/m2
DOI:10.11975/j.issn.1002-6819.2018.20.016
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 29>
Accession number:20190206357022
Title:Identification of diseased empty rice panicles based on Haar-like feature of UAV optical image
Authors:Wang, Zhen (1, 2); Chu, Guikun (1); Zhang, Hongjian (1); Liu, Shuangxi (1, 2); Huang, Xincheng (3); Gao, Farui (3); Zhang, Chunqing (4); Wang, Jinxing (1, 2)
Author affiliation:(1) College of Mechanical and Electronic Engineering, Shandong Agricultural University, Tai'an; 271018, China; (2) Shandong Provincial Key Laboratory of Horticultural Machineries and Equipment, Tai'an; 271018, China; (3) Jining Agricultural Research Institute, Jining; 273013, China; (4) College of Agronomy, Shandong Agricultural University, Tai'an; 271018, China
Corresponding author:Wang, Jinxing(jinxingw@163.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:73-82
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Empty rice panicles are a common pest and disease characteristic in rice fields that affects the rice yield and quality. In order to achieve accurate prevention and control of pests and diseases in rice fields, in this study, a multi-rotor UAV-loaded industrial CCD digital camera was used as the image acquisition platform to rapidly and accurately identify and locate the empty rice panicles in large area rice fields based on the Haar-like feature extraction and Adaboost training algorithm. We used the method of UAV aerial photography technology to perform video capture of large area rice fields on a scheduled route. The interval frame number of the sample image was calculated by parameters such as the flight speed of the UAV, aerial video speed, aerial altitude, and the angle of camera, then the video of the rice field was processed by image disassembly, frame extraction, image mosaic, etc. to achieve efficient and rapid acquisition of image information of large area rice fields. The training sample database and the test sample database for the test were finally formed according to the position information of the rice field coordinate in the frame image extracted by the image extraction interval frame number. After many preprocessing operations, such as compression, cutting, normalization, background separation, threshold segmentation, noise removal, etc., the images in the training sample database and the test sample database were applied in the Haar-like feature extraction and AdaBoost training. In this study, we designed four kinds of Haar-like features, such as edge feature of class A, linear feature of class B, center feature of class C and extension feature of class D, these four kinds of Haar-like features and their combination features were rapidly extracted by the integral diagram calculation, then input the extracted Haar-like features into Adaboost training. During the calculation process, we took each discrimination threshold based on the Haar-like features as a weak classifier to give iterative cycle training, after T times iterative cycles. Then T weak classifiers were obtained, and the strong classifier was obtained after cascading the weights of the T weak classifiers. After the Adaboost training, the obtained strong classifier minimized the misjudgment rate of weak classifiers at all levels in each cycle of iteration. We then took the Haar-like eigenvalue extracted by the unrecognized samples as the input of the strong classifier, based on eigenvalue weight, the strong classifier gave a assessed value H to judge whether it was the empty rice panicles or not. When the H was 1, it meant that the classification result was empty rice panicles. When the H was -1, the tested sample was not the empty rice panicles. In this way, identification of empty rice panicles was realized. In order to ensure the diversity and adequacy of the test samples, the influence of the interference factors such as various forms of the empty rice panicles, lighting, shielding, adhesion and background etc. were fully considered. Two hundred and eight five images and a total of 700 positive and negative samples in the training sample database were used for Haar-like feature extraction and AdaBoost learning training. Sixty five images and a total of 800 positive and negative samples in the test sample database were used to verify the performance of strong classifier. The experimental results showed that among the four Haar-like features and their combined features, the class C and class D Haar-like combined features had better performance in improving classifiers than other features. The strong classifiers generated by this combined features were then used to identify the 423 empty rice panicles samples in the test, among which, three hundred and ninety six were identified, and the recognition rate was 93.62%. Our results demonstrated that this method could effectively inhibit the influence of complex backgrounds such as the rice leaves shielding, rice panicles adhesion and lighting etc., and it was also suitable for field identification of empty rice panicles in natural environment. In the study, this method was compared with algorithms that used texture recognition, such as shear waves, contour waves, curve waves, etc. The experiment showed that this method has significant advantages both in the accuracy and the speed of recognition.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:32
Main heading:Classification (of information)
Controlled terms:Adaptive boosting - Adhesion - Aerial photography - Algorithms - Antennas - C (programming language) - Database systems - Disease control - Diseases - Eigenvalues and eigenfunctions - Extraction - Feature extraction - Geometrical optics - Image acquisition - Image segmentation - Iterative methods - Lighting - Partial discharges - Sampling - Shear flow - Shear waves - Shielding - Unmanned aerial vehicles (UAV)
Uncontrolled terms:Background separation - Classification results - Discrimination thresholds - Empty rice panicles - Haar-like features - Pre-processing operations - Prevention and controls - Threshold segmentation
Classification code:631.1 Fluid Flow, General - 652.1 Aircraft, General - 701.1 Electricity: Basic Concepts and Phenomena - 716.1 Information Theory and Signal Processing - 723 Computer Software, Data Handling and Applications - 741.1 Light/Optics - 742.1 Photography - 802.3 Chemical Operations - 921.6 Numerical Methods - 931.1 Mechanics - 951 Materials Science
Numerical data indexing:Percentage 9.36e+01%
DOI:10.11975/j.issn.1002-6819.2018.20.010
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 30>
Accession number:20190206357035
Title:Analysis on single kernel weight and oil content of different grain types in maize based on NMR
Authors:Li, Haochuan (1); Qu, Yanzhi (1); Yang, Jiwei (1); Cui, Liyang (1); Mao, Xilan (1); Liu, Zonghua (1)
Author affiliation:(1) College of Agronomy, Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, Zhengzhou; 450002, China
Corresponding author:Liu, Zonghua(zhliu100@163.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:183-188
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Maize haploid breeding as an important technology of modern breeding programs can shorten breeding cycles and enhance the breeding efficiency. The method of haploid produced by in vivo has become a routine process and has been adopted widely in maize breeding. The rapid and accurate recognition of haploid kernels is a prerequisite for in vivo haploid breeding technology. Therefore, how to efficiently select haploid seeds from mass hybridization kernels has been an issue during the use of parthenogenetic haploid. At present, spectral information and image recognition based on the gene R-nj expressing Navajo marker in kernels were usually used to automatically sort haploids in maize, but the expression of gene R-nj were significantly depended on the maternal genetic backgrounds, it is unavailable for some flint germplasms with the presence of a supressor. With the development of inducers with high oil and high inducing rate, the automatic sorting of maize haploid kernels become a reality based on nuclear magnetic resonance (NMR). The embryo of haploid only developed from female gamete without the fusion of the sperm cell, so the oil content of haploid kernels is usually lower than that of diploid kernels because of xenia effect. Presently, most studies only set one threshold of oil content to identify haploid and diploid kernels based on NMR. However, there are some embryo abortion kernels with very lower oil content during the process of haploid induction, it is difficult to make distinction among diploid, haploid and embryo abortion kernels based on one threshold of oil content using NMR sorting system. In this paper, the single kernel weight and oil content of diploid, haploid and embryo abortion kernels by in vivo induction were analyzed, respectively, a new concept of increasing the correct discrimination rate of haploid based on two thresholds of oil content was developed. Three different types of kernels were produced by in vivo induction using two common maize hybrids and three inbred lines as females and inducers with high oil content as the males. The measurement of single kernel weight and oil content for three types of kernels were carried out by NMR sorting system. The result showed that the rank of the single kernel weight of different grain types was haploid > diploid > embryo abortion kernels, the highly significant difference existed between diploid and embryo abortion kernels, but there was no difference between diploid and haploid kernels, haploid and embryo abortion kernels. The variation coefficient of the average performance of single kernel weight was 16.62%, lager overlaps appeared among three different types of kernels. The oil content showed that the diploid > haploid > embryo abortion kernels. The coefficient of variation of oil content for diploid kernels was the lowest with only 12.52%, followed by haploid kernels, the highest was embryo abortion kernels with 34.14%, but the oil content was not more than 2% for all the embryo abortion kernels. The step distribution with obvious boundaries for oil content among the three different grain types was found. It indicated that the oil content can be used to recognize among three different types of kernels, but the single kernel weight cannot be as a sorting standard. According to the oil content, minimum of diploid and maximum of embryo abortion kernels were set respectively as the upper and lower limit value to form double thresholds, which could improve the rate of correct discrimination for haploid and provide a reference during the process of automatically sorting haploid kernels with high efficiency.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:24
Main heading:Nuclear magnetic resonance
Controlled terms:Crops - Efficiency - Gene expression - Grain (agricultural product) - Image recognition
Uncontrolled terms:Coefficient of variation - Discrimination rates - Haploid - Maize - Nuclear Magnetic Resonance (NMR) - Oil contents - Single kernel - Variation coefficient
Classification code:461.9 Biology - 821.4 Agricultural Products - 913.1 Production Engineering
Numerical data indexing:Percentage 1.25e+01%, Percentage 1.66e+01%, Percentage 2.00e+00%, Percentage 3.41e+01%
DOI:10.11975/j.issn.1002-6819.2018.20.023
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 31>
Accession number:20190206357021
Title:Experiment of cetane number improver on emissions of diesel engine fueled with methanol/biodiesel
Authors:Li, Ruina (1); Wang, Zhong (1); Liu, Shuai (1)
Author affiliation:(1) School of Automobile and Traffic Engineering, Jiangsu University, Zhenjiang; 212013, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:67-72
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Methanol and biodiesel are the oxygenated alternative fuels of diesel engine, which can effectively reduce particulate emissions of diesel engines. However, due to the low cetane number of methanol, it is difficult for methanol to ignite in diesel engine. The addition of cetane number improver is an effective method to improve the ignition performance of diesel engine fuels. In order to study the effects of different cetane number improvers on diesel engine emission pollutants, three kinds of cetane number improvers, such as alkyl nitrates, naphthyl nitrates and ethers were chosen and added to the methanol / biodiesel blend fuel with the mixing ratios of 0.3%, 0.3%, and 3%, respectively. The effects of the cetane number improvers on the physical and chemical properties of methanol/biodiesel blend were investigated. The engine bench test was carried out on the 186F diesel engine without adjusting the structure of the diesel engine during the test. The in-cylinder pressure and exhaust temperature of the diesel engine fueled with methanol/biodiesel blend was measured at 1 800, 3 000 r/min, 25%, and 100% load, then the ignition delay and combustion duration were calculated. The variation of pollutants such as HC, CO, NO<inf>X</inf> and smoke emitted from the diesel engine at 1 800 and 3 000 r/min, 10%, 25%, 50%, 75% and 100% loads were measured. The effects of cetane number improvers on diesel engine exhaust pollutants were investigated. The results showed that the addition of cetane number improvers had little effects on the density, viscosity and other physical and chemical properties of the methanol/biodiesel blend, but the cetane number of the blend was obviously increased. Because of the low decomposition activation energy of the cetane number improvers, the improvers can help the blend to shorten the chemical delay period. With the addition of cetane number improvers to the methanol/biodiesel blend, the in-cylinder pressure peak was increased, the ignition delay was shortened, and the combustion duration was prolonged. In addition, the corresponding crankshaft angle of in-cylinder pressure peak was advanced. When the amount of improvers was equal, the ignition delay period of alkyl nitrates mixture was the shortest among the three cetane number improvers. When the diesel engine changed from 25% load to 100% load, the exhaust temperature was increased by 194-235 K at the same speed. While the diesel engine speed had smaller effects on the exhaust temperature and the variation range was -3.24%-3.45%. With the addition of cetane number improvers, the HC and CO emission were increased, especially at higher engine load. However, the addition of cetane number improvers can reduce the NO<inf>X</inf> and the smoke. When the diesel engine was at 3 000 r/min, 100% load, NO<inf>X</inf> was reduced by 12.90%, 6.45%, 3.87% with the addition of alkyl nitrate, naphthenic nitrates and ethers respectively, and the smoke was reduced by 11.76%, 17.65%, 38.24%. The addition of cetane number improver in methanol/biodiesel blends not only can improve the ignition characteristics of the fuels, but also reduce NOx and particulate emissions.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:19
Main heading:Diesel engines
Controlled terms:Activation energy - Alternative fuels - Biodiesel - Blending - Chemical properties - Crankshafts - Emission control - Engine cylinders - Ethers - Ignition - Methanol - Methanol fuels - Nitrates - Particulate emissions - Smoke
Uncontrolled terms:Cetane number improver - Combustion duration - Decomposition activation energy - Diesel engine emissions - Exhaust temperature - Ignition characteristics - In-cylinder pressures - Physical and chemical properties
Classification code:451.1 Air Pollution Sources - 451.2 Air Pollution Control - 521.1 Fuel Combustion - 523 Liquid Fuels - 601.2 Machine Components - 612.1.1 Internal Combustion Engine Components - 612.2 Diesel Engines - 801 Chemistry - 802.3 Chemical Operations - 804.1 Organic Compounds - 804.2 Inorganic Compounds
Numerical data indexing:Percentage -3.24e+00% to 3.45e+00%, Percentage 1.00e+01%, Percentage 1.00e+02%, Percentage 1.18e+01%, Percentage 1.29e+01%, Percentage 1.76e+01%, Percentage 2.50e+01%, Percentage 3.00e+00%, Percentage 3.00e-01%, Percentage 3.82e+01%, Percentage 3.87e+00%, Percentage 5.00e+01%, Percentage 6.45e+00%, Percentage 7.50e+01%, Rotational_Speed 1.80e+03RPM, Rotational_Speed 3.00e+03RPM, Temperature 1.94e+02K to 2.35e+02K
DOI:10.11975/j.issn.1002-6819.2018.20.009
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 32>
Accession number:20190206357049
Title:Effects of different pretreatment methods on quality and drying characteristics of Poria cocos after harvest
Authors:Zhang, Ping (1, 2); Zheng, Zhian (1, 2); Jiang, Qingwu (3)
Author affiliation:(1) College of Engineering, China Agricultural University, Beijing; 100083, China; (2) China Research Center for Agricultural Mechanization Development, China Agricultural University, Beijing; 100083, China; (3) Anhui Jinzhai Qiaokang Yao Ye Co., Ltd, Liu'an; 237000, China
Corresponding author:Zheng, Zhian(zhengza@cau.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:294-304
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In order to optimize the drying process and to make the quality of Poria cocos under control, in this study, the traditionally sweated, steamed, and directly peeled and cut Poria cocos (without pretreatments) were evaluated through quality and drying kinetics to examine the relevance between pretreatments and the quality of Poria cocos and drying. Results showed that: 1) pretreatments played a dominant role in the quality control of Poria cocos. ① By comparing the mass fraction of water-soluble polysaccharides, Poria cocos after traditional sweating were 1.5 times higher than those without pretreatment and 1.7 times higher than those after steaming. The mass fraction of water-soluble polysaccharides of Poria cocos after steaming was significantly lower than that of those without pretreatment. ② The mass fraction of triterpenes of Poria cocos after traditional sweating was significantly lower than that of those after other two pretreatments. No statistical difference was found between steaming and no pretreatment. By controlling the sweating time and sweating temperature to maintain the mass fraction of tritrpenes. ③ Because of the material migration and accumulation during traditional sweating, Poria cocos after traditional sweating were whiter with better lustre compared with those after steaming (turned yellow and red). 2) Pretreatments is the key factor to affect the drying process. Compared with those with no pretreatment, Poria cocos after traditional sweating and steaming has a different the structure of material (hardness and porosity) and chemical composition (content), which made Bi significantly increased (indicating the increase of heat resistance within the material during the drying process). The shape parameter β was significantly reduced in the range of 0.3-1 (indicating that the drying process was always controlled by the internal water diffusion). The effective water diffusivity and mass transfer coefficient increased significantly, the drying rate increased and the drying time shortened. The steaming pretreatment is more effective in improving drying rate. The results of the study (the visual results displayed by the test data and he theoretical analysis based on the experimental data,) can further optimize the processing technology of Poria cocos, reduce the risk of quality deterioration, study the mechanism of different pretreatment methods on the quality formation of Poria cocos and the change of drying dynamics, and study the mechanism and work of the sweating of Chinese medicinal materials. It provides experimental reference and basis for promoting standardization of primary processing of Chinese medicinal materials by mechanism.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:79
Main heading:Drying
Controlled terms:Deterioration - Diffusion in liquids - Heat resistance - Moisture - Polysaccharides - Process control - Quality control - Risk assessment
Uncontrolled terms:Drying characteristics - Poria cocos - Processing technologies - Quality deteriorations - Statistical differences - Steaming - Traditional sweating - Water-soluble polysaccharides
Classification code:804.1 Organic Compounds - 913.3 Quality Assurance and Control - 914.1 Accidents and Accident Prevention - 951 Materials Science
DOI:10.11975/j.issn.1002-6819.2018.20.037
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 33>
Accession number:20190206357034
Title:Tensile-pullout properties of roots of Magnolia multiflora in different growth stages and stability of slope with its root
Authors:Zheng, Mingxin (1); Huang, Gang (1, 2); Peng, Jing (2)
Author affiliation:(1) School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang; 330013, China; (2) School of Architecture, Huanggang Normal University, Huanggang; 438000, China
Corresponding author:Huang, Gang(627823405@qq.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:175-182
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:To study the root tensile-pullout characteristics of shrubs in different growth periods and analyze their effects on slope protection. A indoor tensile test and a field pull-out test using the roots of Magnolia multiflora which is a typical slope-protection shrubs with a growth period of three months, six months, nine months, twelve months, fifteen months and eighteen months were carried out, respectively. The indoor tensile test and field pull-out test of Magnolia multiflora's roots were conducted at a constant displacement rate of 0.02 mm/s and 10 mm/min, respectively. Under the different growth periods, root mechanical effect indexes and physiological indexes were determined, respectively. Root mechanical effect indexes include the single root tensile resistance, single root tensile strength and root pull-resistance. The physiological indexes include the ground diameter, subterranean biomass and lateral root quality. The two-dimensional finite element method was used to simulate the enhancement of the slope stability in terms of the Magnolia multiflora's roots at different growth stages. The results are as follows: Under different growth periods, the tensile resistance of the Magnolia multiflora's single root increases with the increasing of root diameter according to a good power function, and the tensile strength decreases with the increasing of root diameter according to a good power function, when the single root diameter is constant, both the tensile resistance and the tensile strength increase with the growth period. Under the influence of different growth periods, the pull-resistance increases with the increasing of ground diameter, subterranean biomass and lateral root quantity according to a significant exponential function, the increase rate of the average biological index and the average pull-resistance of the Magnolia magnolia's roots are the largest in the growth period of three to six months. After six months, the average biological index and the average pull-resistance of the Magnolia magnolia's roots decrease with the growth period increasing, the increase rates of the ground diameter decrease from 102.78% to 9.8%, the increase rates of subterranean biomass decrease from 117.55% to 19.70% and the increase rates of lateral root quantity decrease from 104.35% to 6.67%, the increase rates of pull-resistance decrease from 102.78% to 31.55%.The safety factor of Magnolia magnolia's roots slope is greater than that of the bare slope, the increase rates of the safety factor are from 1.09% to 23.36% and the safety factor of the slope increases with the Magnolia magnolia's growth period increasing, which indicates that Magnolia magnolia's roots can improve the stability of slope. The equivalent plastic strain and the maximum displacement decreases with the Magnolia magnolia's growth period increasing, among them, the maximum equivalent plastic strain is reduced by 24% to 72% compared with that of the bare slope. The Magnolia magnolia's roots can effectively reduce the slope's maximum horizontal displacement and vertical displacement at different growth stages, the decreasing proportions of maximum horizontal displacement and maximum vertical displacement is increase with the growth period increasing and the reduction of the maximum horizontal displacement are about half of the maximum vertical displacement, it indicates that the growth and development of roots can effectively reduce the displacement of slopes. This research has important research value and practical significance for the coordinated development of infrastructure construction and ecological environment protection using shrub slopes such as Magnolia magnolia.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:32
Main heading:Slope stability
Controlled terms:Bioinformatics - Biomass - Computer simulation - Ecology - Exponential functions - Physiology - Plants (botany) - Plastic deformation - Safety factor - Slope protection - Tensile strength - Tensile testing - Vegetation
Uncontrolled terms:Biological indicators - Growth period - Pull resistance - Roots - Tensile resistance
Classification code:406.2 Roads and Streets - 454.3 Ecology and Ecosystems - 461.8.2 Bioinformatics - 461.9 Biology - 723.5 Computer Applications - 914.1 Accidents and Accident Prevention - 921 Mathematics
Numerical data indexing:Percentage 1.03e+02% to 3.16e+01%, Percentage 1.03e+02% to 9.80e+00%, Percentage 1.04e+02% to 6.67e+00%, Percentage 1.09e+00% to 2.34e+01%, Percentage 1.18e+02% to 1.97e+01%, Percentage 2.40e+01% to 7.20e+01%, Velocity 2.00e-05m/s
DOI:10.11975/j.issn.1002-6819.2018.20.022
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 34>
Accession number:20190206357020
Title:Low-load combustion and emission characteristics of ethanol/diesel RCCI at different start of injection timing
Authors:Han, Weiqiang (1, 2); Li, Bolun (1, 2); Dong, Chao (3); Pan, Suozhu (1, 2); Li, Xin (1, 2)
Author affiliation:(1) Key Laboratory of Fluid and Power Machinery, Ministry of Education, Xihua University, Chengdu; 610039, China; (2) Key Laboratory of Automotive Measurement, Control and Safety, Xihua University, Chengdu; 610039, China; (3) National Automobile Quality Supervision and Test Center, Xiangyang; 441004, China
Corresponding author:Pan, Suozhu(suozhup@163.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:59-66
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Reactivity controlled compression ignition (RCCI) has great potential for improving thermal efficiency and reducing pollutant emissions. RCCI can also control the combustion phase and suppress the maximum pressure rise rate. The RCCI is characterized by the in-cylinder reactivity stratification, which is formed by directly injecting the high reactivity fuel into the low-active homogeneous gas mixture in the cylinder. Based on a heavy-duty six-cylinder turbocharged diesel engine, in this paper, the influence of different start of injection (SOI) timings of diesel fuel on the low-load combustion and emission characteristics of ethanol/diesel RCCI was studied and compared with the conventional combustion mode (CCM). During the experimental study, the rotation speed of engine was 1500 r/min, the total cycle energy was 1 281 J, the ethanol energy premixed ratio was 40%, the SOI timing was -6, -15, -24, -40 °CA ATDC, respectively, and brake mean effective pressure (BMEP) was 0.098, 0.106, 0.109, 0.093 MPa, respectively. The results showed that,in terms of combustion characteristics, with the advance of SOI timing, the heat release rate of the cold flame stage of RCCI was advanced, the heat release rate increased, and the duration increased. During the stage of high temperature heat release, with the advance of SOI timing, the instantaneous heat release rate of RCCI increased first and then decreased,the in-cylinder average temperature peak gradually increased, and the combustion duration gradually increased, the combustion center of gravity (CA50) was advanced first and then postponed, and the maximum cumulative heat release gradually increased. Compared with the CCM, RCCI had a longer ignition delay, slower combustion speed, longer combustion duration, and lower combustion temperature. With the advance of SOI, the difference of combustion characteristics between CCM and RCCI gradually increased. In terms of emission characteristics, as SOI advances, the NOx emission at RCCI first increased and then decreased, HC gradually decreased, and CO first decreased at a small rate and then increased substantially. Compared with CCM, less NOx was emitted from RCCI combustion mode, and with the advance of SOI, the difference gradually increased. In the earlier SOI, the HC emission of RCCI was smaller, and when the SOI was retarded, the HC emission of RCCI was deteriorated. CO emission from RCCI combustion mode was more than that from CCM, and as SOI advances, the difference gradually decreased. With the advance of SOI, the number of the RCCI particulate matter emission was first decreased and then increased. Compared with CCM, there was a smaller amount of particulate matter from the RCCI combustion mode, especially nuclear mode particulates. With the advance of SOI, the particle surface area concentration of RCCI gradually decreased. Compared with CCM, when the SOI range was from -6 to -24°CA ATDC, the surface area concentration of particulate matter emitted by RCCI was relatively larger, and the difference gradually decreased with the advance of SOI. When the SOI range was from -24 to -40° CA ATDC, the surface area concentration of RCCI particulate matters emitted was smaller compared to CCM, and the difference gradually increased with the advance of SOI. The mass concentration of large particulate matters determined the mass concentration of total particulate matter emission. With the advance of SOI, the mass concentration of particulate matter emission from RCCI combustion mode gradually decreased. The proportion of mass concentration of accumulation mode (>13.3-273.8 nm) particulate matter was increased from 15.88% to 66.36% in the total particulate matter emission. The proportion of mass concentration of coarse mode (>273.8-1 000 nm) particulate matter was decreased from 84.09% to 32.87% in the total particulate matter emission. The total mass of RCCI particulate matter was larger than CCM, and the difference gradually decreased with the advance of SOI.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:36
Main heading:Particulate emissions
Controlled terms:Combustion - Diesel engines - Direct injection - Emission control - Engine cylinders - Ethanol - Ignition - Nitrogen oxides - Timing circuits
Uncontrolled terms:Brake mean effective pressures - Combustion characteristics - Compression ignition - High temperature heat release - Particulate Matter - Particulate matter emissions - Start of injections - Turbocharged diesel engine
Classification code:451.1 Air Pollution Sources - 451.2 Air Pollution Control - 521 Fuel Combustion and Flame Research - 521.1 Fuel Combustion - 612.1.1 Internal Combustion Engine Components - 612.2 Diesel Engines - 713.4 Pulse Circuits - 804.1 Organic Compounds - 804.2 Inorganic Compounds
Numerical data indexing:Energy 1.28e+03J, Percentage 1.59e+01% to 6.64e+01%, Percentage 4.00e+01%, Percentage 8.41e+01% to 3.29e+01%, Pressure 9.30e+04Pa, Rotational_Speed 1.50e+03RPM
DOI:10.11975/j.issn.1002-6819.2018.20.008
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 35>
Accession number:20190206357040
Title:Micro-nano structures surface preparation and its heat transfer characteristics of aluminum-based microchannel in heat exchangers
Authors:Luo, Xiaoping (1); Wang, Wen (1); Zhang, Chaoyong (1); Wu, Di (1)
Author affiliation:(1) School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou; 510640, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:216-224
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Micro-channel enhanced heat transfer research is a fundamental research of micro-channel heat exchangers. Micro-channel heat exchangers, as a new type of heat exchanger, have extensive applications in high heat flux equipment and micro-devices. In agricultural engineering, solar energy has a wide application in agricultural energy. However, there are many problems in the heat dissipation of solar cells. The use of micro-channel heat exchangers can effectively control the temperature of the solar cells, prolong the service life and improve the power generation efficiency. In addition, micro-channel technology can also be used in heat pump air conditioners. Heat pump air conditioners have many applications in animal husbandry. New heat pump air conditioners have adopted micro-channel condensers, which can significantly increase heat exchange efficiency and save energy. Heat pipe technology can be used in temperature control of grain storage, drying system of agricultural products, etc. With the improvement of manufacturing and processing technology, micro-channel heat pipes have become a research hotspot as a new type of heat pipe. In order to study the effect of micro-nano structures surface on the heat transfer characteristics of micro-channel flow boiling, the CuCl<inf>2</inf> solution was used to etch the surface of aluminum micro-channels, and the copper particles deposited on the surface were removed by ultrasonic cleaning to obtain micro-nano structures surface. The contact angle of the surface was measured, droplets were dropped on the surface and quickly spread, the contact angle was approximately 0°, and super hydrophilicity was exhibited. The surface of the micro-nano structures was modified with a fluorosilane solution for a certain period of time, and the surface contact angle was measured to be 160.2°, showing super-hydrophobicity. Only by sanding treatment was smooth surface, and the surface contact angle was measured to be 67.2°, exhibiting hydrophilicity. Flow boiling experiments were performed using three different surface micro-channels. The experimental refrigerant was R141b and the operating pressure was 142 kPa. The whole experimental section can be divided into an aluminum base, a micro-channel, a quartz glass plate and an aluminum cover plate (with a visible window on the aluminum cover plate). At the side of the aluminum base, there were thermocouple measuring holes in the entrance section, the exit section and the middle section. In the middle section was a pair of upper and lower temperature measuring holes with four pairs. There was a temperature measurement hole at the entrance and exit, and a total of 10 thermometer holes. Pressure sensors were installed on the other side of the base entrance and outlet respectively for monitoring inlet and outlet pressure. The micro-channel was composed of 12 parallel rectangular single channels. The width and height of a single channel were 1 and 2 mm, respectively, the interval between channels was 2 mm, and the length of the micro-channel was 240 mm. The mass flow rates were 312.6 and 505.2 kg/(m<sup>2</sup>•s), and the heat fluxes were 3.42-34.6 kW/m<sup>2</sup>. The effects of micro-nano structures surfaces on the heat transfer characteristics at different mass flow rates and heat fluxes were investigated. The experimental results showed that the super-hydrophobic surface had the best heat transfer characteristics under low heat flux, and the minimum superheat required for the onset of nucleate boiling was the lowest, followed by the super-hydrophilic surface. For the overall average heat transfer coefficient, the super-hydrophobic surface maximum increased the heat transfer coefficient by 31.6% relative to the smooth surface under the condition of low heat flux, and the heat transfer coefficient of the super-hydrophilic surface was the largest when the heat flux was raised to a certain value, the maximum heat transfer coefficient was 20.6% higher than the smooth surface heat transfer coefficient. Compared with the super-hydrophobic surface, the super-hydrophilic surface heat transfer coefficient had a smaller proportion of increase, mainly because the super-hydrophilic surface showed the best heat transfer characteristics in the saturated boiling section, and the saturated boiling section had a much larger heat transfer coefficient than single phase flow and sub-cooled boiling section. The super-hydrophilic and super-hydrophobic surfaces had the same micro-nano structures surface. The micro-nano structures surface increased the vaporization cores and the contact area between the refrigerant and the wall surface. The difference was that the super-hydrophobic surface was modified by the fluorosilane solution. Hydrophilic and hydrophobic properties, which affected the detachment of bubbles, making the heat transfer characteristics show different characteristics: the heat transfer characteristics of the super-hydrophobic surface in the region of low heat flux was the best, and super-hydrophilic surface in the region of high heat flux had the best heat transfer characteristics. To continue to increase the heating power, a large number of bubbles were generated in the micro-channel under high heat flux density. Due to the hydrophobic feature of the super-hydrophobic surface, bubbles did not easily separate, the heat transfer begins to deteriorate, and the heat transfer coefficient gradually decreases, even lower than smooth surface.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:33
Main heading:Heating equipment
Controlled terms:Air conditioning - Aluminum - Aluminum coatings - Chlorine compounds - Contact angle - Copper compounds - Domestic appliances - Grain (agricultural product) - Heat exchangers - Heat flux - Heat pipes - Heat pump systems - Heat transfer - Heat transfer coefficients - Hydrophilicity - Hydrophobicity - Industrial research - Mass transfer - Microchannels - Nanosensors - Nanostructures - Plates (structural components) - Pumps - Refrigerants - Solar cells - Solar energy - Surface chemistry - Temperature control - Temperature measurement - Thermocouples - Thermonuclear reactions - Ultrasonic cleaning
Uncontrolled terms:Heat transfer characteristics - Hydrophilic and hydrophobic properties - Micro-channel heat exchangers - Micro-nano structures - Power generation efficiency - Super-hydrophilic - Super-hydrophobic surfaces - Superhydrophobic
Classification code:408.2 Structural Members and Shapes - 541.1 Aluminum - 616.1 Heat Exchange Equipment and Components - 618.2 Pumps - 619.1 Pipe, Piping and Pipelines - 621.2 Fusion Reactors - 641.2 Heat Transfer - 641.3 Mass Transfer - 643.3 Air Conditioning - 657.1 Solar Energy and Phenomena - 702.3 Solar Cells - 731.3 Specific Variables Control - 753.3 Ultrasonic Applications - 761 Nanotechnology - 801.4 Physical Chemistry - 803 Chemical Agents and Basic Industrial Chemicals - 813.2 Coating Materials - 821.4 Agricultural Products - 901.3 Engineering Research - 931.2 Physical Properties of Gases, Liquids and Solids - 933 Solid State Physics - 944.5 Temperature Measuring Instruments - 944.6 Temperature Measurements
Numerical data indexing:Percentage 2.06e+01%, Percentage 3.16e+01%, Pressure 1.42e+05Pa, Size 1.00e-03m, Size 2.00e-03m, Size 2.40e-01m, Surface_Power_Density 3.42e+03W/m2 to 3.46e+04W/m2
DOI:10.11975/j.issn.1002-6819.2018.20.028
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 36>
Accession number:20190206357031
Title:Response of evaporation and transpiration of typical afforestation tree species to climate changes in gully region of Loess Plateau
Authors:Li, Lanjun (1); Song, Xiaoyu (1); Xia, Lu (1); Fu, Na (1); Li, Huaiyou (2); Li, Yaolin (2); Feng, Dan (3)
Author affiliation:(1) State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi'an University of Technology, Xi'an; 710048, China; (2) Xifeng Experiment Station of Soil and Water Conservation, Yellow River Conservancy Committee, Qingyang; 745000, China; (3) Lantian Water Conservancy and Soil and Water Conservation Workstation, Xi'an; 710500, China
Corresponding author:Song, Xiaoyu(songxy@xaut.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:148-159
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The Loess Plateau is the main rain-fed agricultural area in western China, and water shortage is a critical factor restricting vegetation establishment and growth in this region. Under the influence of global climate change in recent years, significant changes have taken place in climate characteristics of the Loess Plateau, which will have a far-reaching impact on evaporation and transpiration under different vegetation conditions. Therefore, there is needed to make a in-depth research on the response of evaporation and transpiration to climate change for typical afforestation tree species, which has remarkable theoretical and practical significance in providing useful indications for tree species selection, water use efficiency improvement and ecosystem restoration. In order to evaluate the effects and mechanism of climate change on evaporation and transpiration of typical artificial afforestation tree species, a field experiment was carried out in the growing season of 2015-2016 (April 15th-October15th) at Nanxiaohegou basin (35°41'-35°44'N,107°30'-107°37'E), a typical small basin in gully region of the Loess Plateau selected by the Yellow River Water Conservancy Commission of China. In three sample plots of Robinia pseudoacacia, Platycladus orientalis and Pinus tabulaeformis, soil physical parameters of three soil depth (0-40 cm, >40-100 and >100-200 cm) and the distribution of root density were measured, and soil moisture content, leaf area index, evaporation, precipitation and meteorology data were observed during the study period, from which simulation models of transpiration and evaporation in three experimental plots were established using Hydrus-1D software. The uncertainty of models parameters were analyzed through the Morris method, and the results showed that parameters of pore size distribution (40-100 cm) (n<inf>2</inf>), saturated water content (40-100cm) (θ<inf>s2</inf>), field water capacity (θ<inf>f</inf>), optimum threshold for root water absorption (h<inf>1</inf>), lower threshold for root water absorption (h<inf>2</inf>), soil water potential for permanent wilting (h<inf>3</inf>), extinction coefficient (μ), and parameter of vegetation interception model (a) had a great influence on transpiration, and the parameters related to the physiological characteristics of vegetation (h<inf>1</inf>, h<inf>2</inf>, h<inf>3</inf>, μ, and a) were the important reasons for the differences in transpiration of three tree species. The measured soil moisture content and evaporation data from 2015 were used to calibrate the model, and the data from 2016 were used to validate the model. Nash-suttcliffe efficiency coefficients were all above 0.700. The calibrated models were used to simulate evaporation and transpiration process under different presupposition scenarios derived from related research on climate characteristics of the study area, and the results showed that: 1) The effects of climate change in the future and different hydrological years on Robinia pseudopodia transpiration were greater than that in evaporation, while the opposite was true for Platycladus orientalis and Pinus tabuliformis. 2) Under all climate scenarios, the amount of transpiration for above tree species were distributed in 128.8-282.6, 99.3-200.3 and 140.5-220.5 mm, respectively, while the amount of evaporation were distributed in 94.6-135.4, 116.5-187.3 and 123.8-212.5 mm, respectively, and the transpiration and evaporation were both shown in the following aspect: the wet year > the normal year > the dry year. 3) As for transpiration, the response degree of three tree species to the climate characteristics of the future and different hydrological years was: Robinia pseudoacacia > Platycladus orientalis > Pinus tabuliformis, when it came to the evaporation, it was just the opposite. 4) In the same period of the future climate scenarios, the amount of transpiration in Robinia pseudoacacia plot was the largest among all tree species in wet and normal year, while in the dry year, the tree species with largest amount of transpiration was Pinus tabulaeformis. 5) The influence of precipitation on the transpiration and evaporation in growing season was stronger than that of temperature, and regression analysis indicated that the precipitation in growing season had a very significant linear function (P<0.01) with transpiration and evaporation for all 3 tree species. This study may provide valuable information for rational management of artificial afforestation tree species and restoration of the local ecological environment.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:45
Main heading:Evapotranspiration
Controlled terms:Climate change - Climate models - Computer software - Ecosystems - Efficiency - Landforms - Moisture determination - Physiological models - Pore size - Precipitation (meteorology) - Reforestation - Regression analysis - Restoration - Sediments - Soil moisture - Soil surveys - Transpiration - Uncertainty analysis - Vegetation - Water absorption - Water management - Water supply
Uncontrolled terms:Artificial afforestation - Future climate scenarios - HYDRUS-1D - Loess Plateau - Physiological characteristics - Soil physical parameters - Tree species selections - Vegetation establishments
Classification code:443 Meteorology - 446.1 Water Supply Systems - 454.3 Ecology and Ecosystems - 461.9 Biology - 481.1 Geology - 483 Soil Mechanics and Foundations - 483.1 Soils and Soil Mechanics - 723 Computer Software, Data Handling and Applications - 802.3 Chemical Operations - 913.1 Production Engineering - 921 Mathematics - 922.1 Probability Theory - 922.2 Mathematical Statistics - 944.2 Moisture Measurements - 951 Materials Science
Numerical data indexing:Size 0.00e+00m to 4.00e-01m, Size 1.24e-01m to 2.12e-01m, Size 1.41e-01m to 2.21e-01m, Size 4.00e-01m to 1.00e+00m
DOI:10.11975/j.issn.1002-6819.2018.20.019
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 37>
Accession number:20190206357037
Title:Simulation and test of thermoelectric output performance of Fresnel high concentration PV/T system
Authors:Yan, Suying (1, 2); Wu, Ze (1); Wang, Feng (1); Ma, Xiaodong (1); Wang, Tao (1); Tian, Rui (1, 2)
Author affiliation:(1) College of Energy and Power Engineering, Inner Mongolia University of Technology, Hohhot; 010051, China; (2) Key Laboratory of Wind and Solar Power Energy Utilization Technology, Ministry of Education and Inner Mongolia Construction, Hohhot; 010051, China
Corresponding author:Wang, Feng(wangfeng@imut.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:197-203
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:High concentration photovoltaic equipped with water cooling, have great potential in achieving cost-effective and clean electricity generation at utility scale, so a point-focus Fresnel high concentrating photovoltaic/thermal (PV/T) system with active cooling methods were proposed in this paper. The device consists of Fresnel lens, dual-axis tracking system, water circulation system, data acquisition system and support structure. An active thermal circulation with coolant fluid can enable heat transfer from the central receiver to a thermal load so that the dissipated heat is collected as usable energy. Water is used as the cooling fluid in the microchannel radiator. The dual-axis tracking system ensures that the high concentrating PV/T array tracks the sun accurately and the inverter helps to output electrical power at the maximum power point. The cooling water flows into the radiator from the water inlet, the GaAs battery is cooled, and the water flows back to the cooling water tank to realize the circulation. The influence factors on the thermoelectric performance of the system were investigated, including the direct irradiance of the sun, the assembly distance between the concentrating elements, the incident angle of the sunlight and the flow rate of the working water. The results showed that the temperature of the surface of the battery was decreased with the flow rate of the cooling water when the flow rate was below to the limit value, while it decreased at a slower rate with the increase of flow rate when the flow rate was higher than the limit value. The power and electrical efficiency were dropped to 0.98 W and 7.4 percent point, respectively, when the distance between the Fresnel lens and the 2<sup>nd</sup>/3<sup>rd</sup> stage concentrators was increased by 2 mm, and the direct normal irradiance value was 226 W/m<sup>2</sup>. Meanwhile, output powers of two experimental instruments were added with the increasing of irradiance, while the difference performance of the instruments was observed clearly. Therefore, it is essential to gain an optimal concentrating element assembly parameter range for the certain Fresnel high concentrating PV/T system. The heat absorption was decreased about 0.25 MJ with the incident angle increased from 0° to 1° and the output power was declined to 6.35 W when the irradiance was 500 W/m<sup>2</sup>. Direct normal irradiance was an important characterization factor affecting the thermal and electricity output. The results indicated that when the direct normal irradiance value was 850 W/m<sup>2</sup>, the highest photovoltaic efficiency value was 26% and the instantaneous thermal efficiency could be achieved to 35% at the same time, which meant the total solar energy conversion efficiency of the high concentrating PV/T system was more than 60%. The real-time electric efficiency of the system was consistent with the trend of direct normal irradiance. Power and electrical efficiency and the output characteristics of the system in the experiment were stable through analyzing errors of direct normal irradiance. The results obtained from this paper are also suitable for the large systems due to the experimental system was consisted with 12 modules. The results provide a reference for adjusting the inlet parameters of the heat exchanger during the actual operation of the Fresnel high concentrating PV/T system.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:21
Main heading:Cooling water
Controlled terms:Conversion efficiency - Cooling - Cost effectiveness - Data acquisition - Electric batteries - Energy conversion - Energy efficiency - Flow of water - Flow rate - Gallium arsenide - Hydraulics - III-V semiconductors - Incident solar radiation - Optical instrument lenses - Radiators - Semiconducting gallium - Solar energy - Solar power generation - Thermal management (electronics) - Thermoelectric energy conversion - Thermoelectricity - Tracking (position) - Water tanks
Uncontrolled terms:Electrical efficiency - Fresnel - GaAs - Irradiance - PV/T system - Thermal efficiency
Classification code:446.1 Water Supply Systems - 525.2 Energy Conservation - 525.5 Energy Conversion Issues - 615.2 Solar Power - 615.4 Thermoelectric Energy - 616.1 Heat Exchange Equipment and Components - 631 Fluid Flow - 631.1.1 Liquid Dynamics - 632.1 Hydraulics - 641.2 Heat Transfer - 657.1 Solar Energy and Phenomena - 701.1 Electricity: Basic Concepts and Phenomena - 702.1 Electric Batteries - 712.1.1 Single Element Semiconducting Materials - 723.2 Data Processing and Image Processing - 741.3 Optical Devices and Systems - 804 Chemical Products Generally - 911.2 Industrial Economics
Numerical data indexing:Energy 2.50e+05J, Percentage 2.60e+01%, Percentage 3.50e+01%, Percentage 6.00e+01%, Percentage 7.40e+00%, Power 6.35e+00W, Power 9.80e-01W, Size 2.00e-03m, Surface_Power_Density 2.26e+02W/m2, Surface_Power_Density 5.00e+02W/m2, Surface_Power_Density 8.50e+02W/m2
DOI:10.11975/j.issn.1002-6819.2018.20.025
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
<RECORD 38>
Accession number:20190206357024
Title:Coupling effects of water and nitrogen on tree growth and soil water-nitrogen distribution in young Populus tomentosa plantations under surface drip irrigation
Authors:He, Yuelin (1); Wang, Ye (2, 3); Zhang, Hongjin (1); Xi, Benye (1); Dai, Tengfei (1); Li, Doudou (1); Hu, Mingyuan (1); Jia, Liming (1)
Author affiliation:(1) Ministry of Education Key Laboratory of Silviculture and Conservation, Beijing Forestry University, Beijing; 100083, China; (2) Research Institute of Forestry, Chinese Academy of Forestry, Beijing; 100091, China; (3) Key Laboratory of Tree Breeding and Cultivation, State Forestry Administration, Beijing; 100091, China
Corresponding author:Jia, Liming(jlm@bjfu.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:34
Issue:20
Issue date:October 15, 2018
Publication year:2018
Pages:90-98
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Soil water and nitrogen nutrients are key factors affecting forest growth, especially for young triploid Populus tomentosa. Water and fertilizer factors have synergistic effects, water deficit can inhibit the absorption of nutrients in forests, and excessive irrigation can easily cause nutrient leaching. Although excessive fertilization can improve the water and nitrogen use efficiency under certain conditions, the large amount of nitrogen remaining in the soil is bound to pollute the environment. At present, many scholars have simulated the soil moisture and nitrogen transport under drip irrigation through indoor soil column simulation test. The research on soil water and nitrogen transport in the field is mainly concentrated in the agricultural and horticultural field, and the key is to monitor nitrogen leaching and nitrogen balance. In the field of forestry, due to the complexity of field conditions and the simplification of evaluation indicators, most studies focus on the effects of different water-nitrogen coupling strategies on tree growth and physiological indicators, few researches were on the distribution of water and nitrogen in root zone. In order to explore the effects of water and nitrogen coupling treatments on growth of Populus tomentosa and water-nitrogen distribution in soil, a field experiment was conducted about 2-year-old triploid Populus tomentosa to investigate the effects of two irrigation levels (W<inf>20</inf>, W<inf>45</inf>) and three fertilizer levels (N<inf>80</inf>, N<inf>150</inf>, N<inf>220</inf>) coupling treatments on increment of diameter at breast height (DBH), dynamic distribution of soil water content (SWC) and mineral nitrogen content (N<inf>min</inf>) in 0-80 cm soil depth under drip emitter in growing season. Results showed that W<inf>20</inf> treatment promoted the growth of DBH during April to July significantly (P<0.05), the interaction of irrigation and fertilizer factors was not significant (P>0.05). SWC was influenced greatly by irrigation treatment, which showed that the SWC of W<inf>20</inf> treatment had reached 11.3% in dry season (from the end of April till the middle of June), 37.5% higher than blank control. There was no significant difference in different treatment (P>0.05)in rainy season (from the late June to early August), because SWC was influenced greatly by precipitation. N<inf>min</inf> was accumulated in 0 - 80 cm soil layer during dry season, especially in 0-20 cm soil layer, which showed positive correlation with fertilization. N<inf>min</inf> moved from topsoil towards deep soil in rainy season, which leached below 80 cm soil layer in W<inf>20</inf> treatment and increased uniformly in 20-80 cm soil layers in W<inf>45</inf>. The average N<inf>min</inf> in 0-80 cm soil layer reached to 44.27 mg/kg in W<inf>45</inf>N<inf>150</inf> treatment in rainy season, which was significant higher than other treatments (P<0.05). N<inf>min</inf> accumulated in 0-80 cm soil layer at the end of growing season. To sum up, N<inf>150</inf> treatment can provide adequate nitrogen content in 0-80 cm soil layer in growing season. Combined with the growth of young trees, W<inf>20</inf> treatment can promote the growth significantly during April to July (P<0.05), and W<inf>45</inf> treatment can meet the water demand for growth of the tree after July.<br/> © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:54
Main heading:Soil surveys
Controlled terms:Drought - Forestry - Growth (materials) - Irrigation - Leaching - Nitrogen - Nitrogen fertilizers - Nutrients - Physiological models - Soil moisture - Soil testing - Soils - Water - Water absorption
Uncontrolled terms:Diameter-at-breast heights - End of growing seasons - Irrigation and fertilizers - Mineral nitrogen content - Nitrogen-use efficiency - Physiological indicators - Surface drip irrigations - Triploid populus tomentosa
Classification code:444 Water Resources - 483.1 Soils and Soil Mechanics - 802.3 Chemical Operations - 804 Chemical Products Generally - 821.3 Agricultural Methods - 951 Materials Science
Numerical data indexing:Age 2.00e+00yr, Percentage 1.13e+01%, Percentage 3.75e+01%, Size 0.00e+00m to 2.00e-01m, Size 0.00e+00m to 8.00e-01m, Size 2.00e-01m to 8.00e-01m, Size 8.00e-01m
DOI:10.11975/j.issn.1002-6819.2018.20.012
Database:Compendex
Compilation and indexing terms, Copyright 2019 Elsevier Inc.
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