<RECORD 1>
Accession number:20174204272503
Title:Influence of deflector angles for orchard air-assisted sprayer on 3D airflow distribution
Authors:Lü, Xiaolan (1); Zhang, Meina (1); Chang, Youhong (2); Lei, Xiaohui (1); Yang, Qingsong (2)
Author affiliation:(1) Institute of Agricultural Facilities and Equipment, JAAS, Nanjing; 210014, China; (2) Institute of Horticulture, JAAS, Nanjing; 210014, China
Corresponding author:Chang, Youhong(cyh@jaas.ac.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:81-87
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Air-assisted orchard sprayers are characterized by a strong airflow that carries the pesticide droplets to the target canopy and assists the plant parts to move so as to allow the whole tree penetrated with pesticide droplets. The airflow distribution and movement characteristics are key parameters of sprayer for droplet deposition on target canopy. In order to study the 3D (three-dimensional) spatial distribution of airflow field from an air-assisted orchard sprayer, this article used ICEM CFD (Integrated Computer Engineering and Manufacturing code for Computational Fluid Dynamics) to establish a geometric model, whose whole structure was meshed, and the k-Ε turbulence model and CFX solver were adopted. The effect of different environmental systems on airflow 3D distribution for air-assisted orchard sprayer was estimated, in which the upper deflector angle was set as 30°, 45°, 60°, and 90°, and the lower deflector angle was set as 0°, 10°, 20° and 30°, respectively. Results show that the 3D spatial distribution model of the airflow from air-assisted orchard sprayer can reflect the airflow distribution directly, and the simulated values of airflow characteristic curve are in good agreement with the measured values. However, in the low airflow velocity region (the velocity below 2 m/s), the simulated velocity values of some sampling points are quite different from measurements. That is caused by the perturbation of the natural wind. In the high airflow velocity region with 1.2 m width, the average relative error between the measured value and the simulated value of wind speed is less than 10%. That can confirm that the simulation results are credible. Meanwhile, airflow guided by deflectors is mainly focused in the area the deflectors pointed to, with no obvious effect on airflow diffusion in the middle area, only increasing the airflow velocity and letting airflow gather near deflector area. So the adjustment of deflector angle should be based on the height of canopy and tree trunk, through setting lower deflector angle to fit the foliage limit of the orchard, and setting upper deflector angle to point at position which is little lower than the topmost of tree canopy in the orchard. For further research, to change airflow velocity of the fan has no significant effect on airflow distribution in the airflow field, and merely increases airflow diffusion region. When the lower deflector angle increases from 0° to 30°, the effect of ground friction resistance on the airflow decreases gradually, and the angle between ground friction resistance and air resistance on both sides increases constantly, so one single air current is divided into 3 air currents gradually. This kind of air distribution on horizontal plane has advantages on blowing branches and leaves and penetrating droplets into fruit tree canopy. The airflow velocity distribution in the vertical direction considerably affects the distribution of spray droplets in canopy. The vertical profile of the airflow velocity should be even along the whole vegetation wall, and matched with the canopy shape curve. But the deflector can only adjust the upper and lower airflow, some deflectors are suggested to be fixed in the middle area for adjusting airflow distribution in vertical direction. This study found that a better effect could be achieved by setting the upper and lower deflectors angle as 30° for spraying in the Chinese general orchard where fruit trees had 3.0-3.2 m height and were planted with 4 m row spacing, and by setting the upper deflector angle of 90° (or removing), and the lower deflector angle of 30° for spraying in trellised orchard. The results can provide the reference for the spraying in the orchard, and the higher spraying efficiency and the reduction of environmental pollution can be achieved through the calibration of sprayer operational parameters. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:30
Main heading:Air
Controlled terms:Agricultural machinery - Computational fluid dynamics - Computer integrated manufacturing - Computer simulation - Drops - Farms - Forestry - Friction - Fruits - Orchards - Pesticides - Plants (botany) - Spatial distribution - Spraying - Three dimensional computer graphics - Turbulence models - Velocity - Velocity distribution - Wind
Uncontrolled terms:3-D (three-dimensional) - Air-assisted sprayer - Airflow characteristics - Average relative error - Deflector - Environmental pollutions - K-epsilon turbulence model - Movement characteristics
Classification code:443.1 Atmospheric Properties - 723.5 Computer Applications - 803 Chemical Agents and Basic Industrial Chemicals - 804 Chemical Products Generally - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 921 Mathematics - 922.2 Mathematical Statistics
Numerical data indexing:Percentage 1.00e+01%, Size 1.20e+00m, Size 3.00e+00m to 3.20e+00m, Size 4.00e+00m, Velocity 2.00e+00m/s
DOI:10.11975/j.issn.1002-6819.2017.15.010
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 2>
Accession number:20174204272527
Title:Comparison and selection of smash pretreatment scheme before dehydration in large scale for water hyacinth
Authors:Du, Jing (1); Qian, Yuting (1); Jin, Hongmei (1); Xu, Yueding (1); Huang, Hongying (1); Chang, Zhizhou (1)
Author affiliation:(1) Circular Agriculture Research Center, Jiangsu Academy of Agricultural Sciences, Nanjing; 210014, China
Corresponding author:Chang, Zhizhou(czhizhou@hotmail.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:266-271
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Water hyacinth (Eichhorniacrassipes) is a noxious weed that has attracted worldwide attention due to its fast spread and congested growth, which lead to serious problems in water way transportation, irrigation, and power generation. On the other hand, it can be a valuable resource with several unique properties. Water hyacinth contains more than 95% water but due to its fibrous tissue and a high energy and protein content, it can be used for a variety of useful applications. In order to achieve theoretical basis for large-scale treatment and disposal project that have overall solution of low cost and high efficiency with water hyacinth, a comparative study of different engineering pretreatment before dehydration and analysis of the processing cost were studied as the test platform of pilot demonstration project of water hyacinth. In this paper, the process of instant smash instant dehydration was used, and two kinds of water hyacinth salvage and water transportation (the water hyacinth loaded directly into the cabin, and the water hyacinth after coarse crushing for salvage ship loaded into 1 m<sup>3</sup>nylon bags and transported to the shore by ship), two modes of shore transfer (tower crane airlines and shore based crane) and three methods of crushing (coarse crushing of salvage ship, smash again by turning the machine two times, and smash again after coarse grinding on salvage ship)were designed and experimented in this study. The results showed that the pretreatment method of two times after the salvage of coarse powder was helpful to reduce the energy consumption of processing dehydration of water hyacinth. The treatment of per tons for water hyacinth needed about 2.5 kW·h. Through analysis of energy consumption of different crushing methods, the results showed that the method of two times after the salvage of coarse powder reduced the transportation cost, along with the need for shore crushing. It improved the grinding and dehydration treatment ability, reduced operation cost and the volume by 70.61%, and increased the transport capacity by 3.4 times for the method of salvage ship coarse powder. After the separation of water hyacinth, the content of N and P were the main nutrients in the extrusion residue, while the K value was the main factor in the extrusion juice. With the increase of the degree of grinding for water hyacinth, the N, P, K nutrient in the extrusion residue was gradually transferred to the juice. The solid-liquid separation effect of water hyacinth after anaerobic fermentation was better than that of water hyacinth direct solid-liquid separation in terms of residue water content reduction and nutrient recovery, and the moisture content of the dewatering residue was reduce to 62.89%, and it was only about 0.06 hours and about 0.7 kW·h after dehydration of per tons with water hyacinth. The results of this study have laid a solid foundation for the final design of the water hyacinth treatment and disposal, which is the treatment scheme of "rough grinding of salvage-transfer-twice crushing-dehydration". © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:25
Main heading:Water treatment
Controlled terms:Biomass - Cost benefit analysis - Cost engineering - Cost reduction - Costs - Cranes - Crushing - Dehydration - Dewatering - Energy utilization - Extrusion - Grinding (machining) - Nutrients - Separation - Ships - Transportation - Tungsten ore treatment - Water content
Uncontrolled terms:Anaerobic fermentation - Emergency treatment - Pilot demonstration projects - Pretreatment methods - Solid liquid separation - Treatment and disposal - Water Hyacinth - Water transportation
Classification code:445.1 Water Treatment Techniques - 525.3 Energy Utilization - 533.1 Ore Treatment - 604.2 Machining Operations - 693.1 Cranes - 802.2 Chemical Reactions - 802.3 Chemical Operations - 911 Cost and Value Engineering; Industrial Economics
Numerical data indexing:Percentage 6.29e+01%, Percentage 7.06e+01%, Percentage 9.50e+01%, Time 2.16e+02s, Volume 1.00e+00m3
DOI:10.11975/j.issn.1002-6819.2017.15.034
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 3>
Accession number:20174204272531
Title:Modeling of materials heat and moisture transfer in open sun drying and experimental validation
Authors:Hao, Wengang (1); Lu, Yifeng (1); Lai, Yanhua (1, 2); Zhang, Zongmin (1); Lü, Mingxin (2)
Author affiliation:(1) School of Energy and Power Engineering, Shandong University, Jinan; 250061, China; (2) Suzhou Institute of Shandong University, Suzhou; 215021, China
Corresponding author:Lai, Yanhua(laiyh@sdu.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:301-307
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Open sun drying has been widely applied in the developing country. It is a popular, effective and economic method for drying and preservation of agricultural products and food, but it has some drawbacks such as degradation of materials quality and larger drying period in ambient environment. In order to solve the problem of uncontrollability and randomness in the process of open sun drying, heat and moisture transfer model of open sun drying materials was studied with theoretical knowledge of heat and mass transfer in this study, and heat and moisture transfer mechanisms of open sun drying materials were analyzed. The heat exchange process of dry materials in the open sun drying process mainly included the absorption of solar radiation heat, the convective heat exchange with the surrounding environment, the heat transfer of long wave radiation and latent heat by water evaporation. Thermal resistance and thermal energy diagram of drying materials was built. Heat balance equation of materials was also built based on energy balance principle, and model parameters were determined by comprehensively considering solar radiation intensity, ambient air temperature and humidity, and ambient wind velocity; the dynamic temperature change of material surface and the water transfer rate of material were predicted, the program was solved by using MATLAB software, and the initial values required for the solution of the model were derived from the experiment data. To verify the accuracy of prediction model, sweet potato was selected as drying material in the open sun drying test. The tested samples of sweet potato were sliced uniformly in terms of size and thickness, the initial mass of sweet potato was 240 g, and the thermal performances and drying characteristics of sweet potato in the open sun drying were investigated in the Qianfo mountain campus of Shandong University. The test period was from 8: 30 to 17: 00 on May 7, 2017. The test parameters included solar radiation intensity, outdoor air temperature and humidity, surface temperature and mass change of sweet potato during the drying process. Fourteen mathematical models were tested to specify the suitable model for describing the drying behavior of the tested samples, and it was found that the Page model was convenient to describe the drying characteristics of sweet potato in open sun drying. During the test period, the solar radiation intensity ranged from 398.91 to 979.9 W/m<sup>2</sup>, the air temperature ranged from 27.2 to 41.2℃, and the sweet potato mass decreased from 240 to 57 g. The determination coefficient were respectively 0.96, 0.89 between the simulated and experimental values in terms of drying materials temperature and mass, and root mean square error were respectively 0.97℃, 28.35 g, and the change trend of simulated and experimental value was consistent, but there were certain differences between them, and especially the difference of dry material mass was large. The main reason for this phenomenon was the model calculation parameters and experimental data had some irrationality. It is concluded that the model can predict accurately the material dynamic change of surface temperature and drying mass rate in the process of open sun drying of materials, and this model can be used in the process control of open sun drying. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:31
Main heading:Drying
Controlled terms:Agricultural products - Air - Atmospheric temperature - Developing countries - Heat exchangers - Heat transfer - Mass transfer - MATLAB - Mean square error - Models - Moisture - Moisture control - Solar dryers - Solar radiation - Surface properties - Thermal processing (foods) - Water absorption
Uncontrolled terms:Absorption of solar radiation - Determination coefficients - Drying characteristics - Energy balance principle - Experimental validations - Heat and moisture transfer - Solar radiation intensity - Unsteady state
Classification code:443.1 Atmospheric Properties - 616.1 Heat Exchange Equipment and Components - 641.2 Heat Transfer - 641.3 Mass Transfer - 657.1 Solar Energy and Phenomena - 731.3 Specific Variables Control - 802.3 Chemical Operations - 804 Chemical Products Generally - 821.4 Agricultural Products - 822.2 Food Processing Operations - 921 Mathematics - 922.2 Mathematical Statistics - 951 Materials Science
Numerical data indexing:Mass 2.40e-01kg, Mass 2.40e-01kg to 5.70e-02kg, Mass 2.84e-02kg, Surface_Power_Density 3.99e+02W/m2 to 9.80e+02W/m2
DOI:10.11975/j.issn.1002-6819.2017.15.038
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 4>
Accession number:20174204272501
Title:Design and experiment of pesticide droplet deposition detection system based on principle of standing wave ratio
Authors:Wu, Yalei (1); Qi, Lijun (1); Zhang, Ya (2); Gao, Chunhua (1); Li, Shuai (3); Musiu, Elizabeth (1)
Author affiliation:(1) College of Engineering, China Agricultural University, Beijing; 100083, China; (2) College of Information and Electrical Engineering, China Agricultural University, Beijing; 100083, China; (3) Department of Mechanical Engineering, North China Electric Power University, Baoding; 071051, 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:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:64-71
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In order to realize the rapid acquisition of droplet deposition after application, this study proposed an interdigitated droplet collecting board structure based on standing wave ratio principle. The purpose of this study was to quickly and effectively obtain the characteristics and regularity of the droplet deposition distribution. On one hand, the system could reduce the experiment cost, the difficulty of operation and the complexity of the experiment. On the other hand, the system was important to evaluate the quality of pesticide application and improve the utilization rate of pesticide. Optimized droplet deposition detection technology could solve the problem of single measurement method and low efficiency of droplet deposition distribution in field, which was a goal pursued by scholars in this research field. Based on the principles of standing wave ratio and sensor network technology, the real-time detection system of droplet deposition on the ground was designed. The droplet distribution characteristics of the electric field were explored by the method of simulation, and then the optimal parameters of the interdigitated droplet collecting board were obtained. At the same time, combined with the greenhouse self-propelled sprayer system, the application test and verification test were carried out to obtain the distribution characteristics of droplet deposition accurately and quickly. The real-time detection system of droplet deposition in the greenhouse could be realized by using the method of standing wave ratio, and the reliability was very high. At the same time, the system had great practical significance in the field of droplet spray quality detection and regularity research. In order to verify the rationality of the interdigitated droplet collecting board structure, the electromagnetic simulation of the system was carried out by using the three-dimensional electromagnetic simulation software HFSS (high frequency structure simulator). The device took the STM32 single chip microcomputer as its core to build the ZigBee network, and the signal of the droplet collection sensor was transmitted to the remote terminal based on LabView2014 through the RS232 serial port, which realized the real-time monitoring of the droplet deposition. The results of the HFSS model showed that the electrostatic shielding appeared inside the interdigitated droplet collection board. The electromagnetic coupling could be realized by the droplets between the boards, which could be used to detect the droplet deposition. The sensitivity of the system would be decreased with the board spacing broadening. The regression equation of the relationship between the output voltage of the detection system and the deposition amount of the reagent solution was established through the calibration experiment. The determination coefficients under 2 different dielectric constants were 0.982 1 and 0.997 6 respectively. The 3W-ZW10 type self-propelled sprayer application test in greenhouse showed that the maximum relative error rate of the simulated value of the deposition amount of the system at the sampling point was not more than 7.95%. The RMSE (root mean square error) of the measured value was 0.076 7 mg/cm<sup>2</sup>. The detection accuracy of droplet deposition was high. The droplet deposition amount detection system can be used for rapid measurement of field droplet deposition rate based on the principle of standing wave ratio. From the laboratory calibration and application test results, it can be concluded that the design of the interdigitated droplet collection system is feasible within the range of 300 μm particle size. The proposed real-time detection method of droplet deposition in greenhouse based on the standing wave ratio is suitable for the detection of the droplet spray quality and the characteristics of droplet distribution. This research can provide reference for the measurement of droplet deposition. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:30
Main heading:Drops
Controlled terms:Calibration - Computer simulation - Computer software - Deposition - Deposition rates - Design - Elastic waves - Electric fields - Electromagnetic shielding - Electromagnets - Greenhouses - Mean square error - Particle size - Pesticides - Sensor networks - Signal detection - Spraying - Zigbee
Uncontrolled terms:Determination coefficients - Distribution characteristics - Electromagnetic simulation - HFSS simulation - High-frequency structure simulators - RMSE (root mean square error) - Single chip microcomputers - Standing-wave ratio
Classification code:701.1 Electricity: Basic Concepts and Phenomena - 704.1 Electric Components - 716.1 Information Theory and Signal Processing - 722.3 Data Communication, Equipment and Techniques - 723 Computer Software, Data Handling and Applications - 723.5 Computer Applications - 802.3 Chemical Operations - 803 Chemical Agents and Basic Industrial Chemicals - 821.6 Farm Buildings and Other Structures - 922.2 Mathematical Statistics - 931.1 Mechanics
Numerical data indexing:Percentage 7.95e+00%, Size 3.00e-04m
DOI:10.11975/j.issn.1002-6819.2017.15.008
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 5>
Accession number:20174204272521
Title:Classification and recognition approaches of tomato main organs based on DCNN
Authors:Zhou, Yuncheng (1); Xu, Tongyu (1); Zheng, Wei (1); Deng, Hanbing (1)
Author affiliation:(1) College of Information and Electrical Engineering, Shenyang Agricultural University, Shenyang; 100866, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:219-226
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Recognition of the main organs of tomato from plant images has important significance for the detection of plant diseases and insect pests, the application of targeted pesticides, and the development of intelligent agricultural machinery. The traditional object recognition methods which are limited by hand-engineered features extraction process and the selection of filter operator types, have poor generality and low recognition accuracy. The convolutional layers of convolutional neural network (CNN) can achieve automatic extraction of image features. In view of this, we propose a tomato main organs recognition method which relies on deep convolutional neural network (DCNN) in this paper. Under different illumination conditions, and considering the morphological diversity of tomato organs, 5 kinds of images including flower, fruit, stem, leaf, and environment background and the plant images are collected, which are used as training and testing samples. Under the premise of maintaining the basic structure of VGGNet, by adjusting the number of convolutional kernels and the depth of convolutional layers, 10 kinds of tomato organs classification networks are constructed. To reduce overfitting on tomato organ image dataset, before using the dataset to train the individual network, we use many data augmentation techniques to enlarge the dataset such as label-preserving transformations, specifically image rotation at random angles, extracting random patches of one image, image flip horizontal, and altering the intensities of the RGB (red, green, blue) channels of training images. At the same time, the median filter is used to denoise image samples. We train our models end to end using stochastic gradient descent with input image size of 64×64 or 128×128 pixels, mini-batch size of 128 examples, and momentum of 0.9. The classification test results show that the 10 kinds of networks all have very good classification performance by top-1 error rate. Among the 10 kinds of networks, the 8-layer structure network's top-1 error rate is 0.297%, which has the best classification performance. The results reveal that 8-layer structure network can satisfy the features extraction and classification requirements of tomato image dataset with fewer categories. Considering the classification performance and computing speed, referencing Fast R-CNN, with the 8-layer structure network as the basic architecture, and using the region of interest pooling (RoI pooling) layer to replace the last maximum pooling (max-pool) layer, a tomato main organ detector is designed, and named as TD-Net. The detector can output the category probabilities for each object proposal through the soft-max layer. The selective search algorithm is adopted for generating a large number of proposal regions for each tomato plant image, and the non-maximum suppression algorithm is used to suppress the outputs of the TD-Net. Using plant images and proposal regions as input, the detector is trained iteratively. The detection experiment results show that the detection average precisions (AP) of the DCNN-based tomato organ detector for the fruit, flower and stem are 81.64%, 84.48% and 53.94% correspondingly, and the detector can effectively identify the fruits of different maturity degree and the flowers of different flower age. On the same tomato plant image dataset, compared with R-CNN and Fast R-CNN, TD-Net has a better detection performance and detection speed, which illustrates that the method of this paper is effective. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:31
Main heading:Image processing
Controlled terms:Agricultural machinery - Classification (of information) - Convolution - Deep learning - Deep neural networks - Extraction - Fruits - Image segmentation - Iterative methods - Median filters - Neural networks - Object recognition - Pixels - Stochastic models - Stochastic systems
Uncontrolled terms:Classification and recognition - Classification performance - Convolutional neural network - Data augmentation - Morphological diversity - Plant diseases and insect pests - Stochastic gradient descent - Tomato organs
Classification code:716.1 Information Theory and Signal Processing - 802.3 Chemical Operations - 821.1 Agricultural Machinery and Equipment - 821.4 Agricultural Products - 921.6 Numerical Methods - 922.1 Probability Theory - 961 Systems Science
Numerical data indexing:Percentage 2.97e-01%, Percentage 5.39e+01%, Percentage 8.16e+01%, Percentage 8.45e+01%
DOI:10.11975/j.issn.1002-6819.2017.15.028
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 6>
Accession number:20174204272499
Title:Air pressure stabilizing method and experiment of pneumatic seed-metering system of precision rapeseed planter
Authors:Liao, Yitao (1, 2); Shu, Caixia (1, 2); Liao, Qingxi (1, 2); Wei, Yuepei (1, 2); Wang, Lei (1, 2); Wang, Du (1, 2); Zheng, Juan (1, 2)
Author affiliation:(1) College of Engineering, Huazhong Agricultural University, Wuhan; 430070, China; (2) Key Laboratory of Agricultural Equipment in Mid-lower Yangtze River, Ministry of Agriculture, Wuhan; 430070, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:49-56
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The tractor load keeps varying randomly during the tractor - pneumatic planter unit working. It could cause the air pressure in pneumatic precision seed-metering system to become not as constant as the design due to the working speed fluctuation of air pump on the planter led by the variation in rotation velocity of the tractor's power output shaft. Consequently, it would deteriorate the distribution uniformity of seeds in the field and worsen the growth and final yield of crops. To solve this problem, an effective air pressure stabilizing method of pneumatic seed-metering system was proposed based on spring-loaded air pressure relief valve. The first step was to measure the rotation velocity of the tractor's power output shaft in the field. After that, the relationships of the speed of the air pump and the air pressure of the pipeline and the seed-metering device were determined through the bench test. Then, the predetermined control point value of air pressure relief valve was estimated, and the structure and working parameters of air pressure relief valve spring were calculated and selected. Additionally, theoretical analysis and experiments were performed to demonstrate the efficiency of the selected relief valve. A practical engineering in precision combined rapeseed planter, called 2BFQ-6, was used to demonstrate the application of proposed air pressure stabilizing method. A field test was conducted to determine the working speed of the air pump and a laboratory test was implemented to confirm the relationships of the air pump working speed, air pressure in the pipes and air pressure in the chamber of seed-metering device. The test results showed that the coefficient of variation of working speed of the air pump was less than 4.38% when the tractor was working with the same gear, and the coefficient of variation was less than 9.2% as the tractor was working with different gear. To ensure persistent seeding of the seed-metering device, the working speed of the air pump should be in the range of 2 020-2 620 r/min. In order to stabilize air pressure of the pneumatic seed-metering system, the predetermined point value of relief valves were 1 000 and -5 500 Pa with positive and negative air pressure respectively. A type of spring-loaded air pressure relief valve was selected and its construction and working parameters were calculated and analyzed. Carbon steel wire cylindrical spiral spring was employed in the valve. The intermediate diameter and the pitch of the spring were 30 and 10 mm respectively. The number of active coils of the spring was 8. The line diameter of the spring was 1.0 mm for positive pressure relief and 1.5 mm for negative pressure relief. The precompression distance of adjustment bolts were 6.7 and 7.8 mm for positive and negative pressure relief respectively. Theoretical analysis based on air pressure - flow rate characteristics verified that the relief valve used in this pneumatic seed-metering system could be used for air pressure adjusting. Furthermore, air pressure and seeding quantity experiments were performed to evaluate the performance of the selected valve as well as to confirm the feasibility of the proposed stabilizing method. The results showed that the positive and negative air pressure of the seed-metering device could range from 200 to 350 Pa and from -3 900 to -3 000 Pa respectively by employing the relief valves, under which the pneumatic seed-metering system could work stably, showing a contrast to the speed fluctuation of the air pump. The air pressure stabilizing system decreased the deviation rate of the positive and negative air pressure in the air chamber of seed-metering device by 45% and 110%, respectively, which facilitated the pressure-regulating response sensitivity and stability to satisfy the requirement. With the increase of the air pump working speed from 2 000 to 2 700 r/min, the coefficient of variation of seeding quantity was 3.84% without the air pressure stabilizing. However, it was reduced to 1.16% when the air pressure stabilizing method with the customized valves was applied, which decreased by 2.68%, indicating the improvement of seeding quantity stability. The research has confirmed that the air pressure stabilizing method by employing air pressure relief valve can effectively solve the problems that the working pressure in the seed-metering device fluctuates when the rapeseed planter works in the field. The method can provide a technical reference for pneumatic planter design and optimization. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:21
Main heading:Pressure relief valves
Controlled terms:Air - Atmospheric pressure - Automobile testing - Carbon - Carbon steel - Control - Experiments - Machinery - Mechanization - Oilseeds - Pneumatic materials handling equipment - Pneumatics - Precision engineering - Pumps - Seed - Speed - Tractors (agricultural) - Tractors (truck)
Uncontrolled terms:Air pressures - Coefficient of variation - Design and optimization - Distribution uniformity - Pneumatic seed-metering systems - Practical engineering - Seed metering devices - Structure and working parameters
Classification code:443.1 Atmospheric Properties - 545.3 Steel - 601 Mechanical Design - 601.2 Machine Components - 618.2 Pumps - 632.3 Pneumatics - 632.4 Pneumatic Equipment and Machinery - 662 Automobiles and Smaller Vehicles - 663.1 Heavy Duty Motor Vehicles - 804 Chemical Products Generally - 821.4 Agricultural Products - 901.3 Engineering Research
Numerical data indexing:Percentage 1.10e+02%, Percentage 1.16e+00%, Percentage 2.68e+00%, Percentage 3.84e+00%, Percentage 4.38e+00%, Percentage 4.50e+01%, Percentage 9.20e+00%, Pressure -3.90e+03Pa to -3.00e+03Pa, Pressure -5.50e+03Pa, Pressure 2.00e+02Pa to 3.50e+02Pa, Rotational_Speed 2.00e+03RPM to 2.70e+03RPM, Rotational_Speed 2.02e+03RPM to 2.62e+03RPM, Size 1.00e-02m, Size 1.00e-03m, Size 1.50e-03m, Size 3.00e-02m, Size 6.70e-03m, Size 7.80e-03m
DOI:10.11975/j.issn.1002-6819.2017.15.006
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 7>
Accession number:20174204272508
Title:Experiment on influence of cover degree, slope and rainfall intensity on sediment concentration of slope runoff in rangeland
Authors:Wang, Dongdong (1); Wang, Zhanli (1, 2); Zhang, Qingwei (1); Zhang, Qilin (1); Tian, Naling (1)
Author affiliation:(1) State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling; 712100, China; (2) Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling; 712100, China
Corresponding author:Wang, Zhanli(zwang@nwsuaf.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:119-125
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The purpose of this study was to model sediment concentration of sheet erosion on rangeland, which has a major impact on strengthening river basin management and controlling the source of soil erosion. The impact of herbaceous vegetation on sediment concentration under different slopes or rain intensities was studied by artificial rainfall experiment. The relationship of sediment concentration and slope gradient, rainfall intensity, and hydraulic parameters, such as shear stress, stream power and unit stream power, was investigated to derive an accurate experimental model. Each experiment soil pan with metal frames was 140 cm long, 120 cm wide and 2.5 cm deep. The experiment soil sample was collected from Ansai County, Shaanxi Province in China. After the soil was packed, herbaceous vegetation (Poa pratensis L.) was transplanted in a banded uniform layout. Poa pratensis L. was a gramineous plant, and the current year's Poa pratensis L. was selected. The duration of all simulated rainfall events was 40 min. The experiment was conducted at 5 herbaceous vegetation cover densities (30%, 40%, 50%, 60%, and 70%), 5 rainfall intensities (0.7, 1, 1.5, 2, and 2.5 mm/min) and 5 slopes (7°, 10°, 15°, 20°, and 25°), respectively. All combinations were tested with 2 replicates of each run, a total of 90 experimental units. All statistical analyses were carried out using Excel or spss 18.0. Results show that: 1) Herbaceous vegetation not only decreases sediment concentration, but also reduces the effect of rainfall intensity or slope on it, which would increase with cover increasing. Cover increases from 30% to 70%, herbaceous vegetation decreases sediment concentration by more than 5 kg/m<sup>3</sup>, and reduces the effect of rainfall intensity or slope on it by more than 10 kg/m<sup>3</sup>. Under different slopes or rainfall intensities, sediment concentration decreases as linear equations with cover, and the relationship between sediment concentration and cover is significant (P<0.01). Under different covers, sediment concentration totally increases as power equations or exponential equations with rainfall intensity or slope, the relationship between sediment concentration and rainfall intensity is very well (P<0.01), and the relationship between sediment concentration and slope is also good (P<0.01). 2) Unit stream power is the parameter most suitably describing sediment concentration with an exponential equation among the 3 hydraulic parameters considered in this paper. Sediment concentration increases as shear stress or stream power increases, and both can be described by a logarithmic equation, but the relationship between sediment concentration and shear stress or stream power is poor. 3) Rainfall intensity, slope and cover can be used to predict sediment concentration with an exponential function accurately, which was satisfactory for predicting sediment concentration with the R<sup>2</sup>value of 0.937 and the NE (Nash coefficient) of 0.894. Meanwhile, unit stream power also can be used to predict sediment concentration with a power function equation, which was satisfactory for predicting sediment concentration with the R<sup>2</sup>value of 0.940 and the NE of 0.986. Vegetation species, layout and root morphology affect the simulation effect of sediment concentration on rangeland. In the later period, the vegetation species, layout and root morphology should be studied to quantify the sediment concentration and optimize the sediment concentration model. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:30
Main heading:Sediments
Controlled terms:Erosion - Exponential functions - Forecasting - Plants (botany) - Precipitation (meteorology) - Rain - Runoff - Sedimentation - Shear stress - Soils - Vegetation - Water management
Uncontrolled terms:Cover - Herbaceous vegetation - Hydrodynamic parameters - Sediment concentration - Soil erosion modeling
Classification code:442.1 Flood Control - 443.3 Precipitation - 483 Soil Mechanics and Foundations - 483.1 Soils and Soil Mechanics - 802.3 Chemical Operations - 921 Mathematics
Numerical data indexing:Mass_Density 1.00e+01kg/m3, Mass_Density 5.00e+00kg/m3, Percentage 3.00e+01%, Percentage 3.00e+01% to 7.00e+01%, Percentage 4.00e+01%, Percentage 5.00e+01%, Percentage 6.00e+01%, Percentage 7.00e+01%, Size 1.20e+00m, Size 1.40e+00m, Size 2.50e-02m, Time 2.40e+03s
DOI:10.11975/j.issn.1002-6819.2017.15.015
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 8>
Accession number:20174204272512
Title:Erosion resistance effects and mechanism of hedgerows in slope of engineering accumulation
Authors:Yang, Shuai (1, 2); Gao, Zhaoliang (1, 3); Li, Yonghong (3); Niu, Yaobin (1, 3); Wang, Kai (1); Bai, Hao (3); Qi, Xingyuan (3); Li, Yutingting (3)
Author affiliation:(1) State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling; 712100, China; (2) University of Chinese Academy of Sciences, Beijing; 100049, China; (3) Institute of Soil and Water Conservation, Northwest A&F University, Yangling; 712100, China
Corresponding author:Gao, Zhaoliang(gzl@ms.iswc.ac.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:147-154
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Engineering accumulation body generated during the process of engineering construction has a unique soil composition and complex underlying surface. This sort of deposit is characterized by weak anti-scour ability attributed to the surface structure of soil loss, loose soil, and plant roots and organic matter deficiency, which may result in the runoff conditions easily causing severe soil erosion. Engineering accumulation body is prone to soil and water loss, which is the emphasis of water and soil conservation in production and construction project. As an effective soil and water conservation measure, hedgerows have been widely used in various types of arable lands. In the present study, hedgerows are adopted to improve the erosion resistance of the slope by runoff scouring tests. The hydrodynamic characteristics are a premise and foundation to understand erosion processes on engineering accumulation body under the condition of hedgerow measure. Thus, a series of studies were conducted for the simulation of runoff erosion process in order to reveal the relationships of main hydrodynamic parameters, such as runoff velocity, depth, flow shear stress, stream power and other relevant parameters, and to explore the erosion control mechanisms of hedgerow on engineering accumulation slope. The study area is located at the Changwu Agricultural Ecological Experimental Station on the Loess Plateau (35°14'24.5″N, 107°40'21.2″E). The established plot was 20 m long and 5 m wide, with 0.5 m thickness of soil generated from slope excavation. There were 3 flow discharges (35, 45, 55 L/min) and 3 slopes (24°, 28°, 32°), and a hedgerow plot was set for each slope and at the same time a bare slope was set as the control; in the hedgerow plot, 4 hedgerows were uniformly arranged from top down. The distance between the highest hedgerow and the upper edge of the slope is 3 m, and the hedgerow spacing is 4 m. A total of 18 field trials were designed in this study. The results showed that the erosion time of the engineering accumulation body focused on the late period of runoff (10-32 min), and the main erosion position was in the middle-upper slope (0-10 m). The cumulative sediment yields of hedgerows plot are reduced by 10%-45% compared to control plot. The relationship between erosion control capability and scouring duration could be stated with quadratic function in which critical time became more early with the increase of slope and flow discharge. In later stage, the sediment concentration in runoff of hedgerows plot exceeded control plot, which could be related to transformation of hedgerows between source and sink. Hedgerows reduce soil detachment rate, increase critical shear stress and critical stream power, and curb rill evolution to develop toward the lower slope. Based on the runoff power, hedgerow slope erodibility (3.58 g/(N·m)) was higher than that of the control surface erodibility parameter (2.83 g/(N·m)). Different slopes and rainfall intensities under the condition of engineering accumulation of hedgerows have good runoff and sediment reduction effect, which may provide a theoretical reference for the rational use of slope protection measures. Meanwhile, fitting the relations between hydrodynamic parameters and soil erosion rate, rill erodibility and critical runoff power can also provide basic parameters for the study on soil erosion on engineering accumulation slope under hedgerow. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:30
Main heading:Runoff
Controlled terms:Agriculture - Erosion - Flowmeters - Fluid dynamics - Hydrodynamics - Sediments - Shear flow - Shear stress - Slope protection - Soil conservation - Soils - Water conservation - Wooden fences
Uncontrolled terms:Engineering constructions - Flow discharges - Hedgerows - Hydrodynamic characteristics - Hydrodynamic parameters - Sediment concentration - Soil and water conservation measures - Water and soil conservations
Classification code:415.3 Wood Structural Materials - 444 Water Resources - 444.1 Surface Water - 483 Soil Mechanics and Foundations - 483.1 Soils and Soil Mechanics - 631.1 Fluid Flow, General - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 931.1 Mechanics - 943.1 Mechanical Instruments
Numerical data indexing:Percentage 1.00e+01% to 4.50e+01%, Size 0.00e+00m to 1.00e+01m, Size 2.00e+01m, Size 3.00e+00m, Size 4.00e+00m, Size 5.00e+00m, Size 5.00e-01m, Time 6.00e+02s to 1.92e+03s
DOI:10.11975/j.issn.1002-6819.2017.15.019
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 9>
Accession number:20174204272529
Title:Spatiotemporal differentiation and driving factors of multi-functionality of land use in county scale in poverty belt around Beijing and Tianjin
Authors:Sun, Piling (1); Xu, Yueqing (1); Liu, Qingguo (2); Liu, Chao (1); Huang, An (1)
Author affiliation:(1) College of Resource and Environmental Sciences, China Agricultural University, Beijing; 100193, China; (2) Qianjiang Xinhua Middle School, Chongqing; 409000, China
Corresponding author:Xu, Yueqing(xmoon@sina.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:283-292
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Multi-functionality of land use is of great significance to promoting regional sustainable development, which has become an important research topic in the field of land resources. In order to explore the spatiotemporal differentiation characteristics of multi-functionality of land use and its influencing factors, poverty belt around Beijing and Tianjin was taken as the study area in this paper. Three land use functions at county level (i.e., production function, living function, and ecological function) were identified and calculated quantitatively. Based on the concept of multi-functionality of land use, an indicator system was established, which was used to evaluate multi-functionality of land use in poverty belt around Beijing and Tianjin in 2000 and 2014 through the method of mean-squared deviation weight decision. The multi-functionality of land use was divided into five levels with natural break jenks, namely, the highest, higher, moderate, lower and lowest. Then, the characteristics of spatiotemporal differentiation of counties (districts) in the study area with different multi-functionality levels were determined. Meanwhile, spatial econometric models were used to identify the key factors that drove spatiotemporal differentiation of multi-functionality of land use. The results showed that: 1) the value of multi-functionality of land use in poverty belt around Beijing and Tianjin was between 0.208 and 0.564 in 2000 and 2014. There was significant spatial polarization in the multi-functionality of land use. Generally, the multi-functionality of land use in poverty belt around Beijing and Tianjin gradually emerged in a descending trend from west to east. The spatial patterns of multi-functionality of land use in the study area changed markedly from 2000 to 2014. The counties (districts) with higher multi-functionality of land use level expanded to Bashang Plateau and mountain areas on the edge of the plateau during 2000-2014. The counties (districts) with moderate level shrunk dramatically and moved toward the east, while the lower and lowest levels tended to be agglomerated in city border-regions. 2) The value of production function of land use ranged from 0.063 to 0.184 in 2000 and 2014 in poverty belt around Beijing and Tianjin. From 2000 to 2014, the spatial pattern of land use production function changed significantly in poverty belt around Beijing and Tianjin. The counties (districts) with the highest level of land use production function mainly spread from the administrative districts to their surrounding regions of Zhangjiakou city. The counties (districts) with higher level moved from the south to the north. The counties (districts) with moderate level moved towards the east, which were mainly distributed in Chengde city. Besides, the lower and lowest levels tended to be agglomerated in city border-regions. The spatial patterns of land use living function and ecological function in 2000 were basically in consistent with the spatial patterns in 2014. Some changes mainly took place in the administrative districts of Chengde city and the regions around the administrative districts of Zhangjiakou city. 3) According to the results of the spatial lag model (SLM), influencing factors of spatial differentiation of multi-functionality of land use tended to be diversified during 2000-2014. The spatiotemporal differentiation of multi-functionality of land use was influenced by national geographical environment, natural resource endowment, socio-economic factors and policy factors. Generally speaking, the spatial pattern of multi-functionality of land use was dominated by national geographical environment and natural resource endowment, which was also driven by socio-economic factors and policy factors. Finally, this study can provide scientific references for the sustainable use of land resources and the decision of land management in the future in the poverty belt around Beijing and Tianjin. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:30
Main heading:Land use
Controlled terms:Agglomeration - Ecology - Economics - Function evaluation - Light modulators - Models - Natural resources - Sustainable development
Uncontrolled terms:Evaluation - Influencing factor - Multifunctionality - Spatio-temporal differentiations - Tianjin
Classification code:403 Urban and Regional Planning and Development - 454.3 Ecology and Ecosystems - 802.3 Chemical Operations - 921.6 Numerical Methods - 971 Social Sciences
DOI:10.11975/j.issn.1002-6819.2017.15.036
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 10>
Accession number:20174204272528
Title:Progress on technologies and mechanism of furfural production from lignocellulose catalyzed by acids
Authors:Wang, Qiong (1); Wang, Wen (1); Qi, Wei (1); Yu, Qiang (1); Tan, Xuesong (1); Zhuang, Xinshu (1); Yuan, Zhenhong (1, 2); Wang, Zhongming (1)
Author affiliation:(1) Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou; 510640, China; (2) Collaborative Innovation Centre of Biomass Energy, Zhengzhou; 450002, China
Corresponding author:Zhuang, Xinshu(zhuangxs@ms.giec.ac.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:272-282
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Furfural is an important high value-added platform chemical derived from lignocellulosic biomass. Domestic and foreign scholars launched various studies of furfural production from biomass, especially in the field of acid catalyzed hydrolysis. In this study, it was reviewed that the progress on technologies and mechanism of furfural production from lignocellulose catalyzed by acids, especially diluted Brönsted acid. The progress status of traditional one-step furfural production technologies was summarized at first, and the problem of large amount of waste water treatment in traditional furfural industry was analyzed. To solve the shortages of one-step technologies, different types of two-step technologies were proposed to achieve the saccharides of hemicellulose to C5 sugars and the dehydration of C5 sugars to furfural separately. The first step of two-step technology was similar to the pretreatment in cellulose ethanol technology, so researchers mainly focus on the second step of furfural preparation from C5 sugars. They invented new methods (such as new solvent systems and catalysts) to increase furfural yields, or improve the economic efficiency of reaction progress by applying effective heating methods or by transferring furfural from reaction system as soon as its generation. In this section, methods of ionic liquid solvent, solid acid catalyst, microwave-assisted heating, organic solvent extraction, supercritical carbon dioxide extraction were studied. Then the new and hot technologies of simultaneous production of furfural and cellulose-derived chemicals, such as 5-hydroxymethylfurfural and levulinic acid were described and evaluated. In the second part, the reaction kinetics of xylose and lignocellulosic biomass catalyzed by diluted Brönsted acids were comprehensively analyzed, and the research progress of related mechanisms was depicted. It was concluded that the kinetic models of the furfural production from lignocellulose were significantly influenced by the acid concentration and temperature. Under higher acid concentration and temperature, the kinetic model was more simple, and close to the "xylose-furfural-degradation products" path or the "xylan-xylose-furfural" path. In the third part, both the mechanisms of furfural generation from xylose and by-products generation from furfural were introduced. In the fourth part, due to Lewis acid catalysis was confirmed important and effective for xylose isomerization to xylulose, and xylulose conversion into furfural was more easier, we summarized the progress and mechanism of xylose conversion into furfural catalyzed by Lewis acid, such as FeCl<inf>3</inf>, SnCl<inf>4</inf>and LiCl. Finally, the research status of the solvent effects in acid/organic solvent reaction systems was concluded, and due to quantum chemistry was used in platform chemical production progress recently, the application of related software was introduced, such as GROMACS. This paper aimed to provide sufficient information for relative scholars to carry out research on furfural production from biomass, and to help scholars to conduct selective research. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:96
Main heading:Furfural
Controlled terms:Aldehydes - Application programs - Biomass - Carbon - Carbon dioxide - Catalysis - Catalysts - Cellulose - Degradation - Enzyme kinetics - Extraction - Ionic liquids - Isomerization - Kinetic parameters - Kinetic theory - Kinetics - Lignin - Lithium compounds - Mechanisms - Organic solvents - Quantum chemistry - Reaction kinetics - Solvent extraction - Solvents - Sugars - Supercritical fluid extraction - Waste treatment - Wastewater treatment - Water treatment
Uncontrolled terms:5 hydroxymethyl furfurals - Acid-catalyzed hydrolysis - Catalyzation - Ionic liquid solvents - Lignocellulosic biomass - Microwave assisted heating - Production technology - Supercritical carbon dioxide extraction
Classification code:445.1 Water Treatment Techniques - 452.4 Industrial Wastes Treatment and Disposal - 601.3 Mechanisms - 723 Computer Software, Data Handling and Applications - 801.4 Physical Chemistry - 802.2 Chemical Reactions - 802.3 Chemical Operations - 803 Chemical Agents and Basic Industrial Chemicals - 804 Chemical Products Generally - 811.3 Cellulose, Lignin and Derivatives - 931 Classical Physics; Quantum Theory; Relativity
DOI:10.11975/j.issn.1002-6819.2017.15.035
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 11>
Accession number:20174204272526
Title:Analysis on xanthan gum solution to simulate flow performance of digestion sludge
Authors:Cao, Xiuqin (1); Yuan, Haiguang (1); Zhao, Zhendong (1); Ding, Hao (1)
Author affiliation:(1) Key Laboratory of Urban Storm Water System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing; 100044, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:260-265
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Anaerobic digestion is a kind of sludge stabilization technology widely used at home and abroad. As an opaque non-Newtonian fluid, it is difficult to obtain the sludge flow characteristics in the digester exactly. Hence, it is necessary to find a sort of transparent fluid to replace it. To ensure the reliability of flow characteristics obtained from transparent analog fluid, it is indispensable to verify the flow similarity with main physical property of the fluid. The feasibility of xanthan gum transparent solution as a similarity solution of digestion sludge was analyzed according to the rheological property and density, respectively, based on the similarity criteria of fluid flow. Under the premise of satisfying the geometric similarity, the Reynolds criterion and the Froude criterion should be met simultaneously, that is, the Reynolds number and the Froude number of 2 kinds of fluids should be equal. The rheological parameter and density of 95% water content digestion sludge and xanthan gum solution at different concentrations were measured by rotating viscometer and gravimetric method severally. The rheological curve of 2 kinds of fluids was tested for a goodness-of-fit, and curve regression effect was characterized by the determination coefficient R<sup>2</sup>on the principle of regression analysis. First, the xanthan gum solution of 13, 16, and 19 g/L was prepared. It was found that the rheological curves of the 16 g/L xanthan gum solution were similar to those of digestion sludge, and both of them were pseudo plastic non-Newtonian fluid, indicating that this xanthan gum solution could replace the sludge as a similarity solution. But, the xanthan gum solution's density was smaller than that of the target fluid in this recipe, which did not conform to the fluid flow similarity criteria. So, for adjusting the density disparity, xanthan gum solution of 14, 15, and 16 g/L was made by using KCl solution as the solvent instead of aqueous solution. Because of the fact that the salt screens the electrostatic repulsions of the trisaccharide side chains, the adoption of a helical backbone conformation is allowed, which in turn promotes the increased association of the ordered xanthan molecules in solution. With the addition of KCl, the rheological curves of 15 g/L xanthan gum solution were in reasonable agreement with those of digestion sludge, which were also typical pseudo-plastic non-Newtonian fluid. The determination coefficients of rheological curve of 2 kinds of fluids were R<sup>2</sup>=0.995 3 (viscosity curve) and R<sup>2</sup>=0.893 5 (shear stress curve), separately, showing the highest similarity. Tracing test of mixing performance displayed that tracer concentrations at the outlet in these 2 kinds of fluids had the same tendency with the change of time. The result of Welch's t-test demonstrated that there was no significant difference in the rheological parameter and density of the 2 kinds of fluids at the significant level of 0.05. Given above logical analysis, it should be pointed out that xanthan gum transparent solution used as a similarity solution of digestion sludge is acceptable, which can be used as a basis method for the flow visualization in the anaerobic digester. Generally, future work should focus on applying transparent similarity solution to validate computational fluid dynamics simulation from the perspective of reducing energy consumption and improving biogas yield. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:33
Main heading:Xanthan gum
Controlled terms:Anaerobic digestion - Computational fluid dynamics - Computer aided software engineering - Energy utilization - Flow measurement - Flow of fluids - Fluids - Non Newtonian flow - Non Newtonian liquids - Potassium compounds - Regression analysis - Reynolds number - Rheology - Shear stress - Sludge digestion - Sludge disposal - Solutions - Viscous flow - Water content
Uncontrolled terms:Gum solutions - Similarity solution - Sludges - T-tests - Tracer experiment
Classification code:452.2 Sewage Treatment - 525.3 Energy Utilization - 631.1 Fluid Flow, General - 723.1 Computer Programming - 804.1 Organic Compounds - 922.2 Mathematical Statistics - 931.1 Mechanics - 931.2 Physical Properties of Gases, Liquids and Solids
Numerical data indexing:Mass_Density 1.50e+01kg/m3, Mass_Density 1.60e+01kg/m3, Mass_Density 1.90e+01kg/m3, Percentage 9.50e+01%
DOI:10.11975/j.issn.1002-6819.2017.15.033
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 12>
Accession number:20174204272514
Title:Improvement of soil surface roughness measurement accuracy by close-range photogrammetry
Authors:Tao, Haoran (1, 2); Chen, Quan (2); Li, Zhen (2); Zeng, Jiangyuan (2); Chen, Xiaoning (1)
Author affiliation:(1) College of Geomatics, Xi'an University of Science and Technology, Xi'an; 710054, China; (2) Airborne Remote Sensing Center, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing; 100094, China
Corresponding author:Chen, Quan(chenquan@radi.ac.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:162-167
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Microwave remote sensing measurements are sensitive to surface parameters, and can be used for quantitative estimation of soil moisture, surface roughness and vegetation information. The ground-based true values of surface roughness parameters are important for the validation and accuracy evaluation of inversion results, and also vital in microwave soil moisture inversion algorithm for calibrating the constants in the model. For a long time, there is a lack of a simple, fast, high-precision method to obtain surface roughness parameters. Firstly, 2 commonly used parameters that characterize surface roughness i.e. root mean square height and correlation length, are described in this paper. Then, the concrete process of surface roughness measurement by close-range photogrammetry is introduced. We also analyze the factors which influence the measurement accuracy of close-range photogrammetry. In addition, close-range photogrammetry results are compared with the traditional pin-profiler method, and the measurement results of the root mean square height and correlation length of the 2 methods are analyzed. It is shown that the mean square root height error measured by the traditional pin-profiler method can reach is 12%-35.1%, and the correlation length error is 19.6%-62.4%. The advantages and disadvantages of the 2 methods are analyzed from the aspects of applicability and accuracy. The accuracy required for microwave inversion of surface roughness parameters is also analyzed. Result shows the way by close-range photogrammetry can improve the accuracy of surface roughness measurement effectively, and meet the requirements of inversion research of soil surface roughness. The influence of sampling interval on roughness measurement accuracy is also analyzed by changing the sampling interval of close-range photogrammetry. This article uses Agisoft Photoscan software to reconstruct point cloud. Specifically, a non-measuring camera is used to obtain multi-angle overlapping image of the study area. Secondly, SIFT (scale-invariant feature transform) approach is used to detect correspondences across the photos. Then bundle-adjustment algorithm is used to solve camera intrinsic and extrinsic orientation parameters and a multi-view approach is utilized to reconstruct dense cloud. Finally, the effect of non-contact measurement can be achieved by measuring the generated dense point cloud. This article also presents the requirements of hardware and image acquisition operations that need paid attention during the measurement of surface roughness using close-range photogrammetry. In this paper, the method of measuring surface roughness by close-range photogrammetry has the following advantages: The accuracy of surface roughness measurement is greatly improved, and the problem of certain surface which is extremely rough and can't be measured is also solved. And the sampling interval of close-range photogrammetry is quantitatively analyzed. Close-range photogrammetric measurement can easily adjust the sampling angle and describe the anisotropy of surface roughness accurately. The number of sampling can be easily increased so as to solve the measurement error caused by the heterogeneity of the surface. At the same time, it is concluded that the measurement result is stable and can be regarded as the true value when the number of measurements is greater than 12. With the advantages of non-contact measurement, high precision, adjustable sampling interval and frequency, the close-range photogrammetric method provides an effective solution for soil surface roughness measurement. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:30
Main heading:Surface roughness
Controlled terms:Cameras - Errors - Measurements - Moisture - Parameter estimation - Photogrammetry - Remote sensing - Roughness measurement - Soil moisture - Soil surveys - Soils
Uncontrolled terms:Close range photogrammetry - Close-range photogrammetric - Microwave remote sensing - Noncontact measurements - Quantitative estimation - Sample intervals - Scale invariant feature transforms - Surface roughness parameters
Classification code:483.1 Soils and Soil Mechanics - 742.1 Photography - 742.2 Photographic Equipment - 931.2 Physical Properties of Gases, Liquids and Solids
Numerical data indexing:Percentage 1.20e+01% to 3.51e+01%, Percentage 1.96e+01% to 6.24e+01%
DOI:10.11975/j.issn.1002-6819.2017.15.021
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 13>
Accession number:20174204272519
Title:Ningxia rice area remote sensing estimation on large scale based on multi-temporal OLI data
Authors:Liu, Jia (1); Wang, Limin (1); Yao, Baomin (1); Yang, Fugang (1); Yang, Lingbo (1); Wang, Xiaolong (1); Cao, Huaitang (1)
Author affiliation:(1) Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing; 100081, China
Corresponding author:Wang, Limin(wanglimin01@caas.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:200-209
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Current researches mostly focus on method and accuracy selection under the condition where data sources are rich but rarely study regional application of multiphase operation land imager (OLI). In this study, Ningxia Hui Autonomous Region was selected for analysis on regional application potential of multiphase OLI data. In order to objectively obtain Ningxia rice area spatial distribution information, to lay a technical foundation for regional crop remote sensing monitoring, and according to the principle of spectral consistency, this paper divided the study area into 6 ground types of rice, sparse forest and shrub, dry land/woodland, abandoned land, wetland/water bodies, and others. The period before July 10, 2016 was taken as the early stage of rice growth. The normalized difference vegetation index (NDVI), infrared reflectance (IR) and short waved index (SWI) were established by choosing the data of OLI carried by US LandSat-8 and using the images taken in the 6 periods of March 11th, April 12th, April 28th, May 30th, June 15th and July 1st. Based on the analysis of dynamic change of 3 indexes of NDVI, IR and SWI, especially on maximum NDVI, minimal IR, and minimal SWI, a decision tree was established, and the identification of rice types in the study area was conducted by using images between March 11 and July 1 of 2016. The basic processes of decision tree classification were: firstly the ground objects such as cities and towns and deserts were eliminated by using maximum NDVI from March to June; the sparse forest and shrubs were eliminated by using maximum NDVI from March to April; the dry land/woodlands were eliminated by using minimum IR from May to June; then wetland/water bodies were eliminated by using minimum IR from March to April; finally, the abandoned lands were eliminated by using minimum SWI from May to June. The remaining pixels were taken as rice. The accuracy verification was conducted by using the highly accurate GF-2 remote sensing (the resolution was 4 m) survey results of rice area background of this region. The extraction accuracy of GF-2 was as high as 99% above. The results showed that the planting area by GF-2 was 91 910 hm<sup>2</sup>and the rice planting area was 88 030 hm<sup>2</sup>by the OLI data. The total extraction error was only -4.22% with the Kappa coefficient of 0.83; the user's classification accuracy of rice spatial distribution was 85.11% with the mapping accuracy of 81.67%. Among the total rice area, the area in Pingluo, Helan, Yingchuan, Qingtunxia, Lingwu, Shapotou, Litong, Yongning, Zhongning, Dawukou and Huinong accounted for 27.71%, 16.76%, 13.69%, 11.87%, 9.93%, 6.72%, 5.34%, 3.27%, 2.24%, 1.60% and 0.87%, respectively. The rice was mostly distributed in the north of Yellow River Irrigation Area. The extraction area based on different phases was different. The rice area proportion of 129/033, 129/034 and 130/034 images was 60.41%, 32.88% and 6.71%, respectively. Compared with the user's accuracy of maximum likelihood supervised classification algorithm on the rice area extraction of 76.98% and the mapping accuracy of 61.66% in this area, the method used in this paper showed an increase of 8.13 percentage points in the user's accuracy, and an increase of even 20.01 percentage points in the mapping accuracy. The result shows that, the method proposed here of establishment of decision classifying tree by using the satellite images of early stage OLI remote sensing time series of rice growth before July 10, and based on the analysis of changing pattern of time series of staple crops can accurately extract the staple crop planting area, and it is a potential method for regional crop area remote sensing monitoring operations. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:36
Main heading:Remote sensing
Controlled terms:Arid regions - Crops - Data mining - Decision trees - Extraction - Forestry - Identification (control systems) - Image analysis - Image processing - Mapping - Maximum likelihood - Maximum likelihood estimation - Spatial distribution - Surveys - Time series - Time series analysis - Wetlands
Uncontrolled terms:Area - LANDSAT - Multi-temporal - Ningxia - Rice
Classification code:405.3 Surveying - 443 Meteorology - 444 Water Resources - 723.2 Data Processing and Image Processing - 731.1 Control Systems - 802.3 Chemical Operations - 821.4 Agricultural Products - 922 Statistical Methods - 961 Systems Science
Numerical data indexing:Percentage -4.22e+00%, Percentage 1.19e+01%, Percentage 1.37e+01%, Percentage 1.60e+00%, Percentage 1.68e+01%, Percentage 2.24e+00%, Percentage 2.77e+01%, Percentage 3.27e+00%, Percentage 3.29e+01%, Percentage 5.34e+00%, Percentage 6.04e+01%, Percentage 6.17e+01%, Percentage 6.71e+00%, Percentage 8.51e+01%, Percentage 6.72e+00%, Percentage 7.70e+01%, Percentage 8.17e+01%, Percentage 8.70e-01%, Percentage 9.90e+01%, Percentage 9.93e+00%, Size 4.00e+00m
DOI:10.11975/j.issn.1002-6819.2017.15.026
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 14>
Accession number:20174204272506
Title:Development and experiment of enhancement precipitation unmanned aerial vehicle adapted to weather and topography of plateau
Authors:Ma, Xueqian (1); Sun, Anping (2); Zhang, Xiaojun (1); Han, Huibang (1)
Author affiliation:(1) Weather Modification Office of Qinghai Province, Xining; 810001, China; (2) Qinghai Meteorological Bureau, Xining; 810001, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:105-111
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The Source Region of Three Rivers is the cradle of China's Yangtze River, Yellow River and Lancang River. It is also a national wetland, a region with biodiversity and ecological fragility. With the economic development and environmental deterioration, the shortage of freshwater resource has become the important obstacle of economic construction and ecological restoration. Development and utilization of freshwater resource in the atmosphere is one of the main ways to solve the shortage of freshwater source on the ground surface. The implementation of artificial enhancement precipitation is an effective mean to the development of cloud water resource in complex weather conditions. The conventional manned aircraft, rocket and artillery operations cannot carry out scientific cloud seeding implementation into complex weather operation field because of some safety and airspace restriction issues, however, unmanned aircraft is a valuable tool to control and recover in meteorological survey and cloud seeding, and it is also an important direction of key technology of equipment research and development in weather modification. It is imperative that the developed unmanned aircraft, which is suitable for the characteristics of the plateau weather, adverse climate and complex terrain, is detectable, operable, controllable and recyclable, and has long voyage and high payload in enhancement precipitation. In the study, the unmanned aircraft of LY-Z200 prototype was employed as the embryonic form; through changing its mode of landing and takeoff, adjusting the engine power and position, and installing the deicer, the flying height and safety were improved. After the installment of sensors of conventional atmospheric detection, small cloud seeding instrument, and aerial photography equipment, the unmanned aircraft was developed completely, which was LY-ZY200 prototype suitable for plateau enhancement precipitation. Using this unmanned aircraft, 4 modification tests showed that the engine power of unmanned aircraft was affected by hypoxia in a high altitude, the flying height was decreased, the takeoff distance was lengthened, and the height of climbing was lowered. Accordingly, the LIMBACH-L550 electric field intensity engine with 31 kW was used to improve the climbing height, and the results displayed that the flight height was up to 6 100 m, the takeoff weight was 171 kg, the payload was 50 kg, the oil volume was 42 L the maximum fuel consumption was 7.2 L/h, the cruising speed was up to 187.2 km/h, and the cruising time was up to 4 h. These indications satisfied the diverse requirements to implement a wide range of the enhancement precipitation task and the loading in the plateau field. The deicing device was installed and the propeller to resist hail was upgraded in the unmanned aircraft to ensure it could normally operate in -4℃ low-temperature cloud field safely and efficiently. The installed sensors of atmospheric temperature, humidity and pressure and the designed small-scale enhancement precipitation seeding device could ensure to carry 10 catalytic lobes and perform scientific operations in appropriate seeding fields. Upgraded flight control and mission systems could achieve information exchange and diverse mission requirements between unmanned aircraft and ground terminal. Using the LY-ZY200 prototype in plateau complex weather conditions, the typical enhancement precipitation test results showed that the unmanned aircraft could pass through the thick cloudy and the complex environment in cloud, achieve a stable, planning and seeding flight, and obviously reflect the effects of enhancement precipitation in cloud seeding on the ground. Consequently, the unmanned aircraft opens an ideal operation mode and provides a detection tool for enhancement precipitation at proper position, time and amount. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:24
Main heading:Cloud seeding
Controlled terms:Aerial photography - Air traffic control - Aircraft - Aircraft control - Aircraft detection - Atmospheric humidity - Biodiversity - Control - Ecology - Electric fields - Engines - Experiments - Fighter aircraft - Flight control systems - Image enhancement - Meteorology - Precipitation (meteorology) - Rivers - Rockets - Temperature - Unmanned aerial vehicles (UAV) - Water - Water resources - Weather modification
Uncontrolled terms:Development and utilizations - Ecological restoration - Economic constructions - Electric field intensities - Environmental deterioration - Information exchanges - Plateau - Research and development
Classification code:431.5 Air Navigation and Traffic Control - 443 Meteorology - 444 Water Resources - 454 Environmental Engineering - 454.3 Ecology and Ecosystems - 641.1 Thermodynamics - 652 Aircraft and Avionics - 654.1 Rockets and Missiles - 701.1 Electricity: Basic Concepts and Phenomena - 716.2 Radar Systems and Equipment - 742.1 Photography - 901.3 Engineering Research
Numerical data indexing:Mass 1.71e+02kg, Mass 5.00e+01kg, Power 3.10e+04W, Size 6.10e+03m, Time 1.44e+04s, Velocity 5.20e+01m/s, Volume 4.20e-02m3
DOI:10.11975/j.issn.1002-6819.2017.15.013
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 15>
Accession number:20174204272516
Title:Design of trapezoidal cut-throated flume and its hydraulic performance simulation and test
Authors:Ran, Danjie (1); Wang, Wen'e (1); Hu, Xiaotao (1)
Author affiliation:(1) Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Area, Ministry of Education, Northwest A&F University, Yangling; 712100, China
Corresponding author:Wang, Wen'e(wangwene@nwsuaf.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:177-183
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Accurate flow measurement is a fundamental component of water management. Owing to their good hydraulic characteristics and easy maintenance, trapezoidal channels have been widely used in terminal water convey systems of China. Previous research indicated that the measuring flume is one of the most accepted and used structures for water discharge measurement. We designed trapezoidal cutthroat flumes to measure the discharge in terminal trapezoidal channels. These flumes can improve flow measuring accuracy without sacrificing water head. We also researched the relationship between channel specification and the flume's parameters for its application. Based on the RNG k-Ε three-dimensional turbulence model along with the TruVOF technique, experiments and corresponding simulations were performed for 14 working conditions on the trapezoidal cut-throat flume with discharges up to 75 L/s to determine its hydraulic performance. Hydraulic performance of the flume obtained from simulation analyses was later compared with observed results based on time-averaged flow field, flow pattern, and velocity distribution. The comparison yielded a solid agreement between the results from 2 methods with the relative error below 10%. On the basis of reliable consequences simulated numerically, analyses of hydraulic performances in detail were carried out. The flow in the upstream of the flume was slow flow with almost parallel flow direction, then the water surface was gradually declined along the contraction segment and the water on both sides tended to converge at the center line. Owing to the severe contraction of the throat section, the water surface near the downstream of the throat section was dramatically declined and the lowest point appeared. From the posterior part of the diffusion section, the water depth gradually increased to the downstream depth with the water depth uniformly distributed in the horizontal section. By analyzing the variation of velocity and total head along the flume under different discharges, it was concluded that both velocity and total head loss accelerated dramatically near the throat. The turbulent dissipation was concentrated in the area near the wall and the bottom of the flume. Regression models developed for upstream depth versus discharge under different working conditions were satisfying with the relative error of 9.21%, which met the common requirements of flow measurement in irrigation areas. Furthermore, the maximum water head loss of the trapezoidal cut-throat flume was less than 10% of the total head. Compared with long-throat flumes, Parshall flumes and parabolic flumes, the head loss of trapezoidal cut-throat flume in trapezoidal channels was less. The three-dimensional turbulence model along with the TruVOF technique allowed one to reproduce the hydraulic characteristics of flow through trapezoidal cut-throat flume in trapezoidal channels. Due to the shorter time demand and lower cost of numerical simulations, compared to experimental studies in predicting the hydraulic characteristics, the simulation of the flow in trapezoidal cut-throat flume in trapezoidal channels based on a properly validated model provided the flow characteristics of these flumes for various flow configurations encountered in the terminal channel. All in all, it is concluded that the trapezoidal cutthroat flume has the advantages of simple structure, low price and high accuracy, plus low head loss. This study provides a reference for the flow measurement of terminal channels in irrigation areas. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:29
Main heading:Rivers
Controlled terms:Buoyancy - Canals - Discharge (fluid mechanics) - Flow measurement - Flow of fluids - Flow patterns - Flow rate - Irrigation - Numerical analysis - Parallel flow - Regression analysis - Turbulence models - Velocity - Velocity distribution - Water management
Uncontrolled terms:Flow charac-teristics - Fundamental component - Head loss - Hydraulic characteristic - Hydraulic performance - Three-dimensional turbulence - Trapezoidal-throated flume - Turbulent dissipation
Classification code:407.2 Waterways - 631 Fluid Flow - 631.1 Fluid Flow, General - 821.3 Agricultural Methods - 921.6 Numerical Methods - 922.2 Mathematical Statistics - 931.2 Physical Properties of Gases, Liquids and Solids
Numerical data indexing:Percentage 1.00e+01%, Percentage 9.21e+00%
DOI:10.11975/j.issn.1002-6819.2017.15.023
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 16>
Accession number:20174204272495
Title:Design and test of rice potted-seedling transplanting mechanism with three transplanting arms
Authors:Wu, Guohuan (1, 2); Yu, Gaohong (2, 3); Xiang, Xiaojie (1); Wang, Linwei (2, 3)
Author affiliation:(1) Department of Mechanical Engineering, Wenzhou Vocational & Technical College, Wenzhou; 325035, China; (2) College of Machinery and Automation, Zhejiang Sci-Tech University, Hangzhou; 310018, China; (3) Zhejiang Province Key Laboratory of Transplanting Equipment and Technology, 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:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:15-22
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Rice potted-seedlings transplanting is one kind of rice planting way, and it can increase the production and improve rice quality because it has the advantages of not hurting root and not needing recovering period. The rice pot seedling transplanting will have a good prospect in the future, but at present the application of rice pot seedling transplanting machine is less in China because there are defects for domestic transplanter with tossing transplanting such as uncontrollable seedling perpendicularity, complex structure, low efficiency and heavy vibration. Foreign rice potted-seedling planting technology is not suitable in China for complicated structure and high cost, and the key to improve the mechanization of rice planting is to research the rice potted-seedling transplanting mechanism suitable to China. Aiming to the above problems, a three-transplanting-arm rice potted-seedling transplanting mechanism of planetary gear train with non-circular gears and incomplete non-circular gear, which is applied in automatic rice potted-seedling transplanter, was designed. The mechanism consists of an incomplete non-circular gear, 3 pairs of conjugate non-circular gears and 3 planting arms, which can transplant seedlings 3 times a week. It means that under the same transplanting efficiency, it can reduce the transplanting spindle rotation, so as to reduce the vibration and improve the success rate of transplanting. Firstly, the shortcomings of the rotary transplanting mechanism with 2 transplanters were analyzed, and the design requirements were put forward. According to the requirements, the implementation plan was advanced. Then, the operation principle of rice potted-seedling transplanting mechanism was introduced, the mathematical expression in parametric form for the trajectory and the equations of non-circular gears and incomplete non-circular gears were derived, and the kinematic model of transplanting mechanism was established. A computer-aided analysis and optimization software of this kind of rice potted-seedling transplanting mechanism was developed with the Visual Basic 6.0. With the method of human-computer interaction based on visualization, the optimization design of the transplanting mechanism was carried out. Using this software, by tuning the design parameters, the influence of every parameter on the optimization object could be found out. The curve of non-circular gears was optimized and the structural parameters were obtained, which can satisfy the requirements of trajectory and attitude in the transplanting process for rice potted-seedling. The 3D (three-dimensional) model of transplanting mechanism was built and assembled in UG's entity modeling module. The virtual prototype was imported into Adams software after the interference checking of 3D model assembly was finished. According to the comparison between the virtual prototype simulation and the theoretical analysis of VB (Visual Basic), the trajectory of them was fundamentally consistent, so the correctness of the model of VB was verified, and the simulation results initially showed the design of mechanism was rational. In order to further verify the correctness of the design, the core components of transplanting mechanism were machined and assembled. Then, the physical prototype of the transplanting mechanism was developed to carry out the kinematics test in the test shelf. The results turned out that the static trajectory of the elastic tip of this transplanting arm and transplanting posture were basically consistent between the virtual prototype simulation and the physical prototype test, which proved the rationality and effectiveness of the parameters of transplanting mechanism. And the feasibility of this transplanting mechanism was verified. At the same time, the mechanism proposed solved the problem of seedling lodging and low transplanting success rate, and the efficiency of transplanting was improved. The research can provide a theoretical basis for developing transplanting mechanisms of rice potted-seedling. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:26
Main heading:Gears
Controlled terms:Computer aided analysis - Computer software - Curve fitting - Design - Efficiency - Human computer interaction - Kinematics - Machinery - Mechanization - Optimization - Seed - Software prototyping - Testing - Trajectories - Virtual prototyping - Visual BASIC
Uncontrolled terms:3-D (three-dimensional) - Complicated structures - Mathematical expressions - Rice potted seedling - Rotary transplanting mechanisms - Transplanters - Transplanting mechanisms - Virtual prototype simulation
Classification code:601 Mechanical Design - 601.2 Machine Components - 723 Computer Software, Data Handling and Applications - 821.4 Agricultural Products - 913.1 Production Engineering - 921.5 Optimization Techniques - 921.6 Numerical Methods - 931.1 Mechanics
DOI:10.11975/j.issn.1002-6819.2017.15.002
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 17>
Accession number:20174204272504
Title:Spray target detection based on laser scanning sensor and real-time correction of IMU attitude angle
Authors:Liu, Hui (1); Li, Ning (1); Shen, Yue (1); Xu, Hui (1)
Author affiliation:(1) School of Electrical and Information 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:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:88-97
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Precise target characteristics detection could provide important parameters for smart variable-rate sprayers. In order to diminish the influence of complex terrain conditions, 3 kinds of dynamic attitude angle deviation correction methods were proposed to mitigate the errors of Lidar-based spray target detection caused by roll angle, pitch angle and yaw angle respectively. An experimental vehicle integrated with a laser scanning sensor detection unit and an inertial measurement unit (IMU) was used to detect spray targets under complex road conditions. The laser sensor detection unit was capable of detecting spray targets with the laser scanner. The inertial measurement unit was able to detect the real-time attitude angle deviations of the vehicle. The dynamic roll correction adopted real-time measured roll angles to correct detection targets and 3-D (three-dimensional) reconstruction images using re-matching trigonometric function and laser scanning polar coordinate value. For the dynamic pitch correction, re-combination of laser scanning target frames and detection points under the guidance of pitch angle values averaged segmentally was used to diminish dynamic pitch angle deviations. The coefficient value of laser scanning depth data combined with yaw angle average values was applied for the dynamic yaw correction. According to the measured vehicle dynamic attitude angle deviations, these 3 kinds of dynamic attitude angle deviation correction methods were put forward to obtain accurate characteristics of the targets and 3-D reconstruction images. The verification experiments for the proposed correction methods to overcome complex field road conditions were divided into 3 test steps. Firstly, an artificial tree and a cuboid chosen as targets were detected with specified detection distances and laser travel speeds to verify pitch correction algorithm when single dynamic pitch angle changed under downhill or uphill terrain. Secondly, the artificial tree was selected as the laser scanning target to test the correction algorithms when dynamic pitch angles combined with roll angles existed under long wooden unilateral bridge terrain. Finally, the artificial tree and the cuboid cabinet were selected as the laser scanning target to verify the correction methods under uneven complex terrain. The data correction process and 3-D image reconstruction were conducted using MATLAB software. The experiment results of 3 steps showed that the maximum relative errors of the height and width of cuboid cabinet were 8.89% and 8.00% respectively after the correction. The relative errors of the height, width and canopy height of the artificial tree were 5.63%, 10.00% and 5.00%, respectively. The 3-D reconstruction images also had significant improvements after the correction. The test results verify the effectiveness of the proposed data correction methods for laser attitude angle deviations correction under complex road conditions. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:28
Main heading:Image reconstruction
Controlled terms:Agricultural machinery - Errors - Forestry - Image enhancement - Image processing - Landforms - Laser applications - MATLAB - Roads and streets - Scanning - Sensors - Spraying - Surface analysis - Transportation - Units of measurement - Vehicles
Uncontrolled terms:3-D reconstruction images - 3D image reconstruction - 3D reconstruction - Attitude angle - Data correction methods - Inertial measurement unit - Maximum relative errors - Trigonometric functions
Classification code:406.2 Roads and Streets - 481.1 Geology - 744.9 Laser Applications - 821.1 Agricultural Machinery and Equipment - 902.2 Codes and Standards - 921 Mathematics - 951 Materials Science
Numerical data indexing:Percentage 1.00e+01%, Percentage 5.00e+00%, Percentage 5.63e+00%, Percentage 8.00e+00%, Percentage 8.89e+00%
DOI:10.11975/j.issn.1002-6819.2017.15.011
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 18>
Accession number:20174204272532
Title:Suitable inorganic salt and its content inhibiting tension of oil-water interface with wheat germ lipase
Authors:Chen, Zhongwei (1, 2); Sun, Jun (1); Wang, Likun (1); Wu, Qifei (2); Xu, Bin (1)
Author affiliation:(1) School of Food and Biological Engineering, Jiangsu University, Zhenjiang; 212013, China; (2) College of Food Process Engineering, Jiangsu University, Zhenjiang; 212013, China
Corresponding author:Xu, Bin(xubin@ujs.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:308-314
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The stabilization of lipase is an important means to control the rancidity of highly oil-containing agricultural products, such as wheat germ. In this paper, the effects of different concentrations of Na<sup>+</sup>, K<sup>+</sup>, Ca<sup>2+</sup>and Mg<sup>2+</sup>on the oil-water interface characteristics of wheat germ lipase A (LA) were examined, based on the interfacial enzymatic analysis methods using interfacial tension meter and rotary rheometer. Firstly, the influence of the different concentrations of wheat germ LA on the interfacial tension of oil-water was studied to determine the concentration of LA system for the subsequent investigation about the effects of inorganic salts on the oil-water interface. Then, the interface tension and rheological properties of the oil-water after adding monovalent and divalent metal salt were studied to explore the effects of species and concentration on the oil-water interface. Next, the effects of different kinds of inorganic salts on the surface tension and rheological properties of oil-water interface, where there were lipase-acting substrate and product, namely, glycerol trioleate and oleic acid, were studied. Finally, the potential mechanism of inhibiting the catalytic activity of metal ions of inorganic salt in inhibiting wheat germ LA activity was discussed. The results showed that, when the concentration of LA was 1.70×10<sup>-6</sup>mol/L, the monovalent metal ions Na<sup>+</sup>and K<sup>+</sup>were more favorable to decrease the interfacial activity of oil-water and the interfacial activity of wheat germ LA, than other divalent metal ions, i.e. Mg<sup>2+</sup>and Ca<sup>2+</sup>. And the effect of Na<sup>+</sup>was higher than that of K<sup>+</sup>. In the divalent metal ions, Ca<sup>2+</sup>could decrease the interfacial tension at a low concentration and increase interfacial tension at a high concentration, while Mg<sup>2+</sup>was opposite to Ca<sup>2+</sup>. At the same time, the decrease effect of Ca<sup>2+</sup>on the interfacial tension was more obvious than Mg<sup>2+</sup>. Besides, the effects of glycerol trioleate and oleic acid on the interfacial properties of wheat germ LA were studied; the effect extent was glycerol trioleate > oleic acid, and the concentration of these 2 compounds was 1.0×10<sup>-5</sup>and 5.0×10<sup>-6</sup>mol/L, respectively. Under the 2 concentrations of glycerol trioleate and oleic acid, adding Na<sup>+</sup>(10<sup>-6</sup>mol/L), K<sup>+</sup>(10<sup>-6</sup>mol/L), Ca<sup>2+</sup>(10<sup>-4</sup>mol/L), and Mg<sup>2+</sup>(10<sup>-9</sup>mol/L)to the oil-water system, could reduce the interfacial tension of oil and water, and then reduce the effect of wheat germ lipase. In summary, inorganic salts play an important role in the inhibition of interfacial activity of wheat germ LA mainly by reducing the catalytic effect through affecting the aggregation behavior of wheat germ LA in oil-water interface and the structure of substrate, and play a role of passivating wheat germ LA. The results of this paper can provide theoretical support for the regulation of lipase activity and wheat germ stabilization in wheat germ industry. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:28
Main heading:Phase interfaces
Controlled terms:Agricultural products - Calcium - Catalyst activity - Chloride minerals - Glycerol - Interfaces (materials) - Interfacial energy - Lipases - Metal ions - Metals - Oleic acid - Rheology - Salts - Stabilization
Uncontrolled terms:Aggregation behavior - Divalent metal salts - Inorganic salts - Interfacial activity - Interfacial property - Oil water interfaces - Rheological property - Wheat germ
Classification code:461.9 Biology - 482.2 Minerals - 531.1 Metallurgy - 549.2 Alkaline Earth Metals - 801.4 Physical Chemistry - 803 Chemical Agents and Basic Industrial Chemicals - 804 Chemical Products Generally - 804.1 Organic Compounds - 821.4 Agricultural Products - 931.1 Mechanics - 951 Materials Science
DOI:10.11975/j.issn.1002-6819.2017.15.039
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 19>
Accession number:20174204272511
Title:Experiment on strength and permeability of recycled aggregate pervious concrete
Authors:Chen, Shoukai (1, 2); Yang, Qing (1, 2); Liu, Qiuchang (1); Guo, Lei (1, 2); Wang, Lunyan (1, 2)
Author affiliation:(1) School of Water Conservancy, North China University of Water Resources and Electric Power, Zhengzhou; 450011, China; (2) Water Environment Governance and Ecological Restoration Academician Workstation of Henan Province, Zhengzhou; 450002, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:141-146
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:To prepare pervious concrete with recycled concrete aggregate is a hot point and the trend of the current research, while strength and water permeability are the key performance highlighted and to be broken through at present. With waste prefabricated concrete beam members as the source of recycled aggregate, pervious concrete was prepared, and 6 groups of mixture ratios were designed with water cement ratio of 0.3 and sand ratio of 10% as the benchmark. Besides, through the experiment on test cubes under standard maintenance, the porosity, water permeability and strength performance of recycled aggregate pervious concrete (RPC) under a single factor were studied. The grain size of coarse aggregate was 4.75-9.5 mm and the natural coarse aggregate (NCA) came from gravels. With the pervious concrete prepared with 100% recycled coarse aggregate as the benchmark, 5 kinds of pervious concretes were designed on the premise of not changing the water-binder ratio and sand ratio: 1) ordinary pervious concrete (wholly made of natural aggregate); 2) equivalent replacement of 20% cement with fly ash; 3) equivalent replacement of 6% cement with silica fume; 4) adding naphthalene superplasticizer equivalent to 1% of the mass of the cement; 5) external addition of steel fiber equivalent to 3% of the mass of the cement. To reduce the influence of the high water absorption of the recycled coarse aggregate, the method of increasing additional water compensation was adopted and the amount of additional water was determined as the amount of water absorbed in 10 min by the recycled coarse aggregate. On the basis of the test and research of the capillary water absorption of concrete by predecessors, a capillary water absorption device for pervious concrete was self-made. It was measured in the experiment that the range of porosity, permeability coefficient and compressive strength was 17.8%-23.8%, 0.27-0.57 cm/s and 4.0-9.63 MPa respectively. According to these results, the basic performance of pervious concrete made of recycled aggregate could satisfy the requirements. Compared with RPC, adding fly ash could realize effective improvement of the compressive strength of the pervious concrete to 9.63 MPa, an increase of about 44%, the external addition of steel fiber could improve the water permeability, and the mixing of naphthalene super plasticizer and silica fume didn't have obvious effect. Admixtures and additives would both exert adverse effect on the splitting tensile strength, and their affecting degree was super plasticizer, fly ash < silica fume < steel fiber. The ratio of the measured splitting tensile strength to the compressive strength (ratio of tension to compression) was 9.5%-16.9%, with the average value being 13.5%. The water permeability increased with the increase of the porosity, and the two presented an exponential relationship, which was basically consistent with the description of ordinary pervious concrete. In addition, it was figured out in the experiment that the maximum capillary water absorption height was 19.4 mm, and the maximum immersion amount in capillary water absorption was 0.01 g/cm<sup>3</sup>; the water absorption height of RPC internally doped with 20% fly ash was about 13.5 mm, while the amount of water absorbed was about 28 g, both values being consistent with the test results of capillary water absorption of existing ordinary concrete in terms of the order of magnitude. In nondestructive condition, the capillary water absorption process of previous concrete made of recycled aggregate was similar with that of ordinary concrete, namely, fast absorption in the early stage and steady absorption in the late stage. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:28
Main heading:Water absorption
Controlled terms:Aggregates - Cements - Compressive strength - Concrete aggregates - Concrete mixing - Concrete mixtures - Concretes - Fly ash - Mechanical permeability - Naphthalene - Plasticizers - Porosity - Recycling - Reinforced plastics - Silica - Silica fume - Steel fibers - Tensile strength - Water recycling
Uncontrolled terms:Capillary water absorption - Cementing material - Non-destructive conditions - Performance - Pervious concrete - Recycled coarse aggregate - Recycled concrete aggregates - Splitting tensile strength
Classification code:406 Highway Engineering - 412 Concrete - 412.1 Cement - 452.3 Industrial Wastes - 802.3 Chemical Operations - 803 Chemical Agents and Basic Industrial Chemicals - 804.1 Organic Compounds - 817.1 Polymer Products - 819.4 Fiber Products - 931.2 Physical Properties of Gases, Liquids and Solids
Numerical data indexing:Mass 2.80e-02kg, Percentage 1.00e+00%, Percentage 1.00e+01%, Percentage 1.00e+02%, Percentage 1.35e+01%, Percentage 1.78e+01% to 2.38e+01%, Percentage 2.00e+01%, Percentage 3.00e+00%, Percentage 4.40e+01%, Percentage 6.00e+00%, Percentage 9.50e+00% to 1.69e+01%, Pressure 4.00e+06Pa to 9.63e+06Pa, Pressure 9.63e+06Pa, Size 1.35e-02m, Size 1.94e-02m, Size 4.75e-03m to 9.50e-03m, Time 6.00e+02s, Velocity 2.70e-03m/s to 5.70e-03m/s
DOI:10.11975/j.issn.1002-6819.2017.15.018
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 20>
Accession number:20174204272498
Title:Effects of axial flow and tangential flow mechanical threshing on rice damage and milling quality
Authors:Li, Yinian (1); Chen, Junsheng (1); Ding, Qishuo (1); Ding, Weimin (1)
Author affiliation:(1) School of Engineering, Nanjing Agricultural University, Nanjing; 210031, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:41-48
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Rice grains would be damaged by the mechanical threshing equipment during harvesting, and mechanical damage extent of rice grains was directly correlated to the threshing cylinder patterns and operating parameters of threshing cylinder, such as roration speed of cylinder and threshing time. On the other hand, there were not objective and whole indices to appraise the mechanical threshing damage extent of rice grains. In order to ascertain the effect of harvest pattern with different mechanical threshing cylinder on rice quality characters, taking manual harvesting rice as control group, the quality characters of the rice harvested by axial flow and tangential flow mechanical threshing cylinder were investigated. The appraisal indices of rice quality characters, fissuring rate and glume-opening rate, germination potential and rate and seedling growth properties, three-point bending breaking force, head rice yield and broken rice rate, were selected and tested according to relevant methods and standards. Experiment results show that the fissuring rate and glume-opening rate for mechanically harvesting rice are higher than that for the hand-harvested rice, and the maximum difference of glume-opening rate is about 35.6%; the fissuring rate and glume-opening rate for axial flow mechanical threshing cylinder are less than that for tangential flow mechanical threshing cylinder. But the germination potential and rate for mechanically harvested rice are lower than that for the hand-harvested rice, and the maximum difference of germination rate is 53%. The germination potential and germination rate for axial flow mechanical threshing cylinder are larger than that for tangential flow mechanical threshing cylinder, and the maximum difference of germination rate is 34%-51%. The stem length and number of roots of rice seedling for axial flow mechanical threshing cylinder and that of the hand-harvested rice are larger than that for tangential flow mechanical threshing cylinder. The maximum differences of the stem length and number of roots between tangential flow mechanical threshing cylinder harvesting and hand-harvesting are respectively 15 mm and 2.4, and those between tangential flow threshing cylinder and axial flow threshing cylinder are respectively 12.6 mm and 1.8. The stem length and number of roots of rice seedling for axial flow mechanical threshing cylinder are adjacent to that for the hand-harvested rice. There are not significant differences for root length and number of leaves and leaves length between the hand-harvested rice and mechanical threshing harvested rice. The three-point bending breaking force for mechanical harvested rice is also lower than that for the hand-harvested rice, and the maximum differences of the three-point bending breaking force for ventral side and dorsal side are 4.5 and 3.8 N respectively. There is not large difference for the three-point bending breaking force between axial flow and tangential flow mechanical threshing cylinder harvesting. The milling quality of hand-harvested rice is also superior to mechanically harvested rice, and the maximum difference of the head rice yield between them is 12.11%. The head rice yield for axial flow mechanical threshing cylinder is 10.38% higher than that for tangential flow mechanical threshing cylinder. The broken rice rate for the hand-harvested rice is correspondingly lower than that for mechanically harvested rice. Cross correlation analysis for all appraisal indices of rice quality characters manifests that the fissuring rate and glume-opening rate are cross-correlated, the germination potential, germination rate and stem length and number of roots for rice seedling are cross-correlated, the three-point bending breaking force for ventral side and dorsal side are cross-correlated, and the milled rice rate and head rice yield are cross-correlated. The mechanical threshing harvest causes the damage to rice quality, and the damage extent of rice quality for different mechanical threshing cylinder harvesting is different. The threshing damage to rice quality for axial flow threshing harvest cylinder is lower than that for tangential flow threshing harvest cylinder. Rice seeds should be harvested by using harvester with axial flow threshing cylinder. On the other hand, the appraisal indices of quality characters of rice seeds harvested by the mechanical threshing cylinder should select the fissuring rate and glume-opening rate, germination potential and rate and seedling growth properties. The appraisal indices of quality characters of food rice harvested by the mechanical threshing cylinder should be the fissuring rate and glume-opening rate, three-point bending breaking force, head rice yield and broken rice rate. The appraisal indices for the rice harvested by mechanical threshing cylinder should been wholly determined according to the used aim of rice. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:29
Main heading:Grain (agricultural product)
Controlled terms:Agriculture - Axial flow - Crops - Cultivation - Cylinders (shapes) - Harvesting - Machinery - Mechanization - Milling (machining) - Processing - Quality control - Seed
Uncontrolled terms:Cross-correlation analysis - Germination potential - Milling quality - Operating parameters - Rice axial flow threshing - Tangential flow - Three point bending - Threshing damage
Classification code:601 Mechanical Design - 604.2 Machining Operations - 631.1 Fluid Flow, General - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 913.3 Quality Assurance and Control - 913.4 Manufacturing
Numerical data indexing:Force 3.80e+00N, Force 4.50e+00N, Percentage 1.04e+01%, Percentage 1.21e+01%, Percentage 3.40e+01% to 5.10e+01%, Percentage 5.30e+01%, Size 1.26e-02m, Size 1.50e-02m
DOI:10.11975/j.issn.1002-6819.2017.15.005
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 21>
Accession number:20174204272520
Title:Natural mowing grassland resource distribution and biomass estimation based on remote sensing in Hulunber
Authors:Yan, Ruirui (1); Tang, Huan (2); Ding, Lei (1); Yao, Jing (1); Chen, Baorui (1); Xin, Xiaoping (1); Wang, Xu (1); Yan, Xiaohong (3); Niu, Wenyuan (3)
Author affiliation:(1) Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Hulunber Grassland Ecosystem Observation and Research Station, Beijing; 100081, China; (2) Tong Ling University, Tongling; Anhui; 244000, China; (3) Inner Mongolia Hotision Monsod Drought Resistant Greening INC, Hohhot; 010000, China
Corresponding author:Xin, Xiaoping(xinxp@sina.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:210-218
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The natural mowing grassland plays an important role in grassland animal husbandry, which is not only the forage reserve resource for ensuring the seasonal balance of grassland and livestock, but also can ensure the safe wintering of livestock as forage grassland and post-disaster emergency rescue of forage grass resources reserves in China. However, the information about the resource distribution and biomass estimate of mowing pasture in natural grassland in China is lacked, which limits the effective utilization of regional forage reserve resources. Therefore, a systematic study on forage harvesting in natural grassland is necessary and important. In this study, the estimation of resource distribution and biomass of Chen Barag Banner in the Hulunber meadow steppe in north-eastern China was carried out by using remote sensing technology and field investigation. The field investigation was conducted in 2015 and the investigation time was from the middle of July to the end of July. The results showed that the area of forage harvesting pasture in the Chen Barag Banner regions was 80.28×10<sup>4</sup>hm<sup>2</sup>, which accounted for 90.37% of fixed harvesting pasture and 9.63% of temporary harvesting pasture. Among them, the largest area of forage harvesting pasture appeared in Ewenke village, reaching 2.28×10<sup>5</sup>hm<sup>2</sup>, followed by Bayanhada village, east Wuzhuer village, Hohnuor village and west Wuzhuer village; the pasture area of each village was larger than 9.00×10<sup>4</sup>hm<sup>2</sup>, and the pasture area of Baorixile village was the smallest, which was 0.64×10<sup>4</sup>hm<sup>2</sup>. Combining the simultaneous MODIS-NDVI (normalized differential vegetation index) datum with biomass investigation of cutting pasture, a relation model between MODIS-NDVI and biomass was developed, and the relative error of the production estimation model was 20.56%. It was feasible for the power function model to be applied in remote sensing monitoring. The average biomass of Chen Barag Banner natural cutting grassland was 1.24×10<sup>3</sup>kg/hm<sup>2</sup>, and the total biomass was 992.90×10<sup>6</sup>kg, among which the largest village biomass was Ewenke village, reaching 304.21×10<sup>6</sup>kg, Bayanhada village was 221.01×10<sup>6</sup>kg, and the other villages accounted for 47.10% of cutting pasture biomass. Temperate steppe (55.94%) and temperate meadow steppe (31.25%) were the main vegetation types for those pastures, and the lowland meadow steppe (4.89%), mountain meadow (5.94%) and desert steppe (1.99%) were distributed with a small area. The area of temperate grassland and temperate meadow grassland was 44.91×10<sup>4</sup>and 25.09×10<sup>4</sup>hm<sup>2</sup>, and the biomass was 532.04×10<sup>6</sup>and 330.87×10<sup>6</sup>kg, respectively. The proportions of grassland area and biomass of other types of grasslands were only 12.81% and 13.09%, respectively. The results have made up for the deficiency for the area data of the region forage harvesting pasture and provided data support for analysis of forage harvesting pasture changes of Chen Barag Banner in the Hulunber meadow steppe of north-eastern China in the future. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:30
Main heading:Vegetation
Controlled terms:Agriculture - Biomass - Harvesting - Models - Radiometers - Remote sensing - Rural areas
Uncontrolled terms:Biomass estimation - Natural mowing grassland - NDVI - Normalized differential vegetation indices - Remote sensing monitoring - Remote sensing technology - Resource distribution - Temperate grasslands
Classification code:821 Agricultural Equipment and Methods; Vegetation and Pest Control - 821.3 Agricultural Methods - 944.7 Radiation Measuring Instruments
Numerical data indexing:Percentage 4.89e+00%, Percentage 5.59e+01%, Percentage 5.94e+00%, Percentage 9.04e+01%, Percentage 9.63e+00%, Percentage 1.28e+01%, Percentage 1.31e+01%, Percentage 1.99e+00%, Percentage 2.06e+01%, Percentage 3.12e+01%, Percentage 4.71e+01%
DOI:10.11975/j.issn.1002-6819.2017.15.027
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 22>
Accession number:20174204272525
Title:Performance of substrate blocks glued by modified urea formaldehyde resins and its effect on cucumber seedlings
Authors:Qu, Ping (1); Zhao, Yongfu (1); Song, Jing (1); Xia, Liru (1)
Author affiliation:(1) Key Laboratory of Agricultural Engineering in the Middle and Lower Reaches of Yangtze River, Institute of Agricultural Facilities and Equipment, Jiangsu Academy of Agricultural Science, Nanjing; 210014, China
Corresponding author:Xia, Liru(liruxiajaas@126.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:253-259
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In order to solve the problem of scattering substrates and the damaged root during the process of mechanized transplanting, the hydrolyzed soy protein modified urea formaldehyde resins were applied to glue the substrates together. The properties of modified resins, such as pH value, viscosity, solid content, density, curing time, and free formaldehyde, were characterized. The nutrient release rate of modified urea formaldehyde resins was characterized. The aeration porosity, water-holding porosity, EC, pH value, and compressive strength of the substrate blocks were also tested; the effect of the substrate block on the cucumber seedling was measured. The results show that the hydrolyzed soy protein modified urea formaldehyde resins can meet requirements of gluing the substrates together. The viscosity and curing time increase obviously. And, the solid content and free formaldehyde decrease a little. The reason is that the viscosity of hydrolyzed soy protein is higher than urea formaldehyde resins, and the solid content is lower than urea formaldehyde resins. The active groups in modified urea formaldehyde resins are fewer than unmodified urea formaldehyde resins. In addition, the space barrier from the soy protein causes the increased curing time, because the hydroxymethyl groups formed from active amino groups of hydrolyzed soy protein and formaldehyde are more stable than that formed from urea and formaldehyde. The nutrient release rate is an important indicator of the substrate block. Soil column leaching method was applied to characterize the nitrogen release rate. The nitrogen release rate in the first 3 weeks is slower. Then the nitrogen release rate is improved in the later time, and the release rate can reach 48% in the 7th week. The reason is the specific surface area increases as the time goes on. The aeration porosity, water-holding porosity, and total porosity of the substrate blocks are decreased by 6.6%, 9.0%, and 8.4% compared with the traditional substrate. The reason is that the porosity and the hydrophilic groups of the substrate are covered by modified urea formaldehyde resins. However, the porosity can meet the growth requirement of the cucumber seedling when the modified urea formaldehyde resins are added in the substrates in the proportion of 1: 2. The EC of substrate block decreases from 2.5 to 1 mS/cm. The pH value of the substrate block remains unchanged. The compress strength of the substrate block is above 0.14 MPa, which can meet the requirement of grabbing of manipulator during the transplanting process. When the modified urea formaldehyde is added, the height, stem diameter, root length are improved by 27.81%, 15.40%, and 18.10%, respectively. And the leaf area, fresh and dry weight are improved by 89.86%, 57.00%, and 79.2%, respectively. In addition, the substrate blocks with 50% resins are suitable for the root growth of cucumber seedlings. III-H-UF is the best resins that the nutrient release rate is in accordance with the nutrient requirement characteristics of the cucumber seedlings. The formula of the substrate blocks is suitable for the cucumber seedlings growth. Every seedling tray increases by 0.9 yuan when blended with modified urea formaldehyde resins. And every seedling increases by 0.0125 yuan for seedling tray with 72 holes. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:28
Main heading:Urea formaldehyde resins
Controlled terms:Compressive strength - Curing - Formaldehyde - Gluing - Hydrolysis - Machinery - Mechanization - Metabolism - Nitrogen - Nutrients - pH - Porosity - Proteins - Resins - Substrates - Synthetic resins - Urea - Viscosity - Water aeration
Uncontrolled terms:Cucumber - Grow seedlings - Physichemical properties - Soy protein - Urea formaldehyde
Classification code:445.1 Water Treatment Techniques - 601 Mechanical Design - 801.1 Chemistry, General - 802.2 Chemical Reactions - 804 Chemical Products Generally - 804.1 Organic Compounds - 815.1.1 Organic Polymers - 931.2 Physical Properties of Gases, Liquids and Solids
Numerical data indexing:Age 5.75e-02yr, Electrical_Conductivity 2.50e-01S/m to 1.00e-01S/m, Percentage 1.54e+01%, Percentage 1.81e+01%, Percentage 2.78e+01%, Percentage 4.80e+01%, Percentage 5.00e+01%, Percentage 5.70e+01%, Percentage 6.60e+00%, Percentage 7.92e+01%, Percentage 8.40e+00%, Percentage 8.99e+01%, Percentage 9.00e+00%, Pressure 1.40e+05Pa
DOI:10.11975/j.issn.1002-6819.2017.15.032
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 23>
Accession number:20174204272502
Title:Aerodynamics modeling and validation on liquid medicine spraying of target weeding robot
Authors:Quan, Longzhe (1); Wang, Jiansen (1); Xi, Dejun (1); Li, Yajun (1); Sun, Wenfeng (1); Chen, Ci (1)
Author affiliation:(1) College of Engineering, Northeast Agricultural University, Harbin; 150030, China
Corresponding author:Sun, Wenfeng(1012208287@qq.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:72-80
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Field weeds have a great effect on the yield of normal economic crops. The commonly used methods of weeding include artificial weeding, mechanical weeding, weed quarantine, biological control, chemical control, and so on. Among those methods, chemical weeding is the best when it comes to sudden grass damage (the weeds of disaster break out suddenly), because it works well and takes less time. However, when we use chemical weeding, there are many problems such as low utilization rate of liquid medicine and serious pollution to the environment with overplus liquid. Therefore, toward-target pesticide application is proposed to solve these problems above all. As we all know, toward-target pesticide application machineries often use machine vision technology to obtain spatial location information of weeds, which makes the nozzle rigidly fixed on the machine and at the same time, the control system adjusts the valve to open and close to achieve the purpose of spraying. On this basis, we use spraying nozzle to change the direction of application, resulting in precision spraying in this paper. In order to study the law of motion for spray droplet, we established dynamic model based on application methods with the principle of aerodynamics, and then the formula of the droplet flying and the analytic formula of the falling point were deduced. Next, the numerical simulation analysis of the covering area was carried out. Especially, in the process of analysis, we discussed the resistance characteristics of spray droplets, the nozzle angle, nozzle speed, machine speed and injection pressure, which affect the movement process we discussed. What's more, the model established above can also be used to control the location and shape of the droplet cover area by adjusting the working parameters, to improve the accuracy of toward-target pesticide application. Furthermore, in order to verify the correctness of the model, we set up the toward-target pesticide application platform and selected the special test site. Under no wind conditions, we conducted a simple target spraying test indoor, and then measured the geometric characteristics of actual liquid dripping place carefully. At the same time, the relevant parameters were obtained by high-speed camera technology. Next, we took the data into the dynamic model mentioned above to get the theoretical coverage of the liquid medicine, which was then compared with the actual coverage of the liquid medicine. Finally, it can be found that there is an error between the calculated and experimental results, and the error range is 8%-13%. In addition, to study the sedimentary characteristics of liquid medicine with this application method, we analysed the distribution law of the deposition amount of liquid medicine in the effective coverage area by water absorption paper weighing method. According to the analysis, it can be seen that the peak value of sediment changes regularly with the parameters such as the change of the nozzle angle, which suggests that the physical background of the model is clear, and the correlation between the parameters of the model and the sprinkler type is small, so the model transplant is strong. In other words, it can be used as a theoretical basis for the relevant spraying machinery. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:29
Main heading:Spray nozzles
Controlled terms:Aerodynamics - Chemical analysis - Computer simulation - Drops - Dynamic models - Dynamics - High speed cameras - Liquids - Machinery - Models - Nozzles - Pesticides - Robots - Visual servoing - Water absorption - Weed control
Uncontrolled terms:Aero-dynamics models - Geometric characteristics - Machine vision technologies - Numerical simulation analysis - Pesticide applications - Resistance characteristics - Sedimentary characteristics - Targeted weeding
Classification code:631.1 Fluid Flow, General - 651.1 Aerodynamics, General - 723.5 Computer Applications - 731.5 Robotics - 742.2 Photographic Equipment - 802.3 Chemical Operations - 803 Chemical Agents and Basic Industrial Chemicals - 921 Mathematics
Numerical data indexing:Percentage 8.00e+00% to 1.30e+01%
DOI:10.11975/j.issn.1002-6819.2017.15.009
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 24>
Accession number:20174204272500
Title:Effect of planosol improvement by using straw subsoil mixed layer plough
Authors:Zhu, Baoguo (1, 2); Zhang, Chunfeng (1, 2); Jia, Huibin (1, 2); Wang, Nannan (1, 2); Meng, Qingying (1, 2); Kuang, Enjun (3); Wang, Qiuju (3); Gao, Zhongchao (3); Liu, Feng (3); Zhang, Libo (1, 2); Gao, Xuedong (1)
Author affiliation:(1) Jiamusi Branch, Heilongjiang Academy of Agricultural Sciences, Jiamusi; 154007, China; (2) The Planosol Improvement Engineering Center of Heilongjiang Province, Jiamusi; 154007, China; (3) Institute of Soil Fertilizer and Environment Resources, Heilongjiang Academy of Agricultural Sciences, Harbin; 150086, China
Corresponding author:Zhang, Chunfeng(chunfeng-1@163.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:57-63
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The subsoil of planosol is usually extremely hard, compacted and poorly nutrient during the growing stage of upland crops. These unreasonable physical-chemical properties of the subsoil trigger the problems on its topsoil, which makes upland crops frequently suffer dry and wet damage so called the surface dry and surface wet damage. Meanwhile it also functions as an obstacle layer limiting root extension, and hence the effective layer of root system of planosol is only about 20 cm. The research formerly carried out has proved that it could cease the problems of subsoil when the Aw (planosol layer) horizon and the B horizon (illuvia horizon) were mixed with the ratio of 1: 1 while leaving the topsoil undisturbed. Through this method, the permeability and the water storage capability of the subsoil were increased. As a result, the machine named the three-stage subsoil mixing plough was developed. Since its working is deeper more than 50 cm, the plough provides the opportunity to return stalks into the mixed subsoil, and the poor nutrient condition of the subsoil can be therefore improved. Based on such kind of principle of planosol improvement, the machine so called the stalk-subsoil mixing plough was developed. This machine can make it come truth to leave the Ap (topsoil) horizon in depth of 20 cm undisturbed, while mixing the subsoil and stalk in depth of 30-40 cm. In this study, the large-size field tests were carried out with the stalk-subsoil mixing plough and the conventional plough at the 854 State Farm of the Sanjiang Plain, Heilongjiang Province of China. The physical-chemical properties after the machine operation were investigated. The agronomic characteristics and yield of the indicating crops were checked. The results showed that compared with the conventional plough, the stalk-subsoil mixing plough could significantly improve the soil physical properties. In the depth of >20-40 cm, soil moisture was increased by 2.69-4.90 percent points; soil hardness was reduced by 44.45%, and there was no hardness peak appearing. In 2014 and 2015, it also could improve soil permeability; solid phase was reduced by 4.51 to 2.14 percent points, water phase was increased by 1.17 to 4.31 percent points, air phase was increased by 0.38 to 0.98 percent points, and soil bulk density was decreased by 0.11-0.16 g/cm<sup>3</sup>. The soil chemical properties were also improved. In the depth where subsoil was mixed with stalks, available nitrogen (N) was increased by17.33%, available phosphorus (P) was increased by 116.39%, available potassium (K) was increased by 37.86%, and organic matter was increased by 36.66%. By the way, soil total N, P, and K and soil pH value were increased. During the 2 years the soybean yield in the field operated by the stalk-subsoil mixing plough was increased by 15.77%-16.33% compared with the field operated by the conventional plough. Thus long term effect for Planosol improvement can be achieved by using the technique of returning stalks. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:28
Main heading:Soils
Controlled terms:Agricultural machinery - Chemical properties - Crops - Forestry - Hardness - Mixing - Nutrients - Physical properties - Soil moisture - Soil testing - Straw - Surface properties
Uncontrolled terms:Available phosphorus - Available potassiums - Mixed layer - Physical chemical property - Planosol - Soil chemical property - Soil improvement - Soil physical property
Classification code:483.1 Soils and Soil Mechanics - 801 Chemistry - 802.3 Chemical Operations - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 931.2 Physical Properties of Gases, Liquids and Solids - 951 Materials Science
Numerical data indexing:Percentage 1.17e+00% to 4.31e+00%, Percentage 1.58e+01% to 1.63e+01%, Percentage 2.69e+00% to 4.90e+00%, Percentage 3.67e+01%, Percentage 3.79e+01%, Percentage 3.80e-01% to 9.80e-01%, Percentage 4.45e+01%, Percentage 4.51e+00% to 2.14e+00%, Size 2.00e-01m, Size 3.00e-01m to 4.00e-01m, Size 5.00e-01m, Age 2.00e+00yr, Mass_Density 1.10e+02kg/m3 to 1.60e+02kg/m3, Percentage 1.16e+02%
DOI:10.11975/j.issn.1002-6819.2017.15.007
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 25>
Accession number:20174204272505
Title:Numerical simulation and validation of effects of blade inlet angle on performance of pump-as-turbine
Authors:Wang, Tao (1, 2); Kong, Fanyu (1); Liu, Yingying (1); Wei, Qineng (3)
Author affiliation:(1) Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang; 212013, China; (2) School of Energy and Power Engineering, Key Laboratory of Fluid and Power Machinery, Ministry of Education, Xihua University, Chengdu; 610039, China; (3) Chengdu Alen Precision Machinery Co., Ltd., Chengdu; 610039, China
Corresponding author:Kong, Fanyu(kongm@ujs.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:98-104
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Small and micro hydropower systems represent an attractive solution for generating electricity at low cost and with low environmental impact. The pump-as-turbine (PAT) approach is promising in this application due to its low purchase and maintenance cost. Due to that the conventional backward-curve centrifugal impellers do not effectively match the turbine's running, the performance of the PAT is usually undesirable. Therefore, to improve significantly the performance of PAT, the method for determining the blade inlet angle that plays an important role in the energy conversion was investigated deeply, and one kind of special impeller with forward-curved blades was designed for the turbine working condition in this paper. Firstly, based on the conservation theorem of angular momentum, the relationship expression between the blade inlet angle and the design flow rate was deduced. Moreover, in order to validate the relationship expression and investigate the effects of the blade inlet angle on the performance of PAT, 4 special impellers with different blade angles were designed by using ANSYS BladeGen and NX software. The validity of numerical simulation was first confirmed through the comparison between numerical and experimental results. The 4 impellers with different blade angles were numerically investigated by use of a verified computational fluid dynamics (CFD) technique. The performance within PATs was investigated through analyzing the external characteristic curves obtained by CFD. The results show that the flow rates of 4 PATs at BEP (best efficiency point) obtained by CFD are about 85, 90, 100 and 110 m<sup>3</sup>/h while the flow rates by theoretical calculation are about 83.6, 90, 99.2 and 108.6 m<sup>3</sup>/h, respectively, as the blade inlet angle is 60°, 72°, 90° and 105°. Based on the results, the flow rate of numerical BEP is very close to that of theoretical BEP, and the flow rate of BEP increases with the enlargement of the blade inlet angles. And, the theoretical relationship expression between the blade inlet angle and the design flow rate presents the effective prediction of the turbine model operations of centrifugal pumps with special impellers. The maximum efficiency of PAT decreases with the increase of the blade inlet angle. And the drop rate of the maximum efficiency increases with the increase of the blade inlet angle. The results indicate that the calculating method of the blade inlet angle is reasonable. Smaller angle is matched with relatively lower rated flow rate while bigger angle with higher rated flow rate. The performance of PAT is better and the high efficiency range is wider when the blade inlet angle is designed in a reasonable range. Additionally, the energy loss within the impeller reaches the minimum if suitable blade inlet angle is selected. So considering the efficiency and the high efficiency range of PAT, the value of blade inlet angle is recommended in a reasonable range between 60° and 90° when the spiral volute of this high specific speed pump is used as turbine flume. This paper is very instructive to the design of the special impeller used in the PAT. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:29
Main heading:Turbomachine blades
Controlled terms:Centrifugal pumps - Computation theory - Computational fluid dynamics - Energy conversion - Energy dissipation - Environmental impact - Flow rate - Impellers - Models - Numerical models - Pumps - Turbine components - Turbines
Uncontrolled terms:Blade inlet angle - Curved blades - Design flow rate - External characteristic - Performance prediction - Pump as turbine (PAT) - Simulation and validation - Theoretical calculations
Classification code:454.2 Environmental Impact and Protection - 525.4 Energy Losses (industrial and residential) - 525.5 Energy Conversion Issues - 601.2 Machine Components - 617 Turbines and Steam Turbines - 618.2 Pumps - 631 Fluid Flow - 721.1 Computer Theory, Includes Formal Logic, Automata Theory, Switching Theory, Programming Theory - 723.5 Computer Applications - 921 Mathematics
DOI:10.11975/j.issn.1002-6819.2017.15.012
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 26>
Accession number:20174204272530
Title:Design and experiment of air-impingement jet combined with normal temperature ventilation dryer for alfalfa
Authors:Yu, Xianlong (1); Gao, Zhenjiang (1); Dai, Jianwu (2); Xue, Lingyang (1); Wang, Dong (3); Wang, Jun (1); Deng, Lizhen (1); Xie, Yongkang (1); Zhang, Xiaolin (1); Xiao, Hongwei (1)
Author affiliation:(1) College of Engineering, China Agricultural University, Beijing; 100083, China; (2) College of Mechanical and Electrical Engineering, Sichuan Agricultural University, Ya'an; 625014, China; (3) College of Mechanical and Electrical Engineering, Shaanxi University of Science and Technology, Xi'an; 710021, China
Corresponding author:Xiao, Hongwei(xhwcaugxy@163.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:293-300
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In order to solve the problems of alfalfa drying, such as smaller drying capacity, high energy consumption, and high leaf loss rate, an alfalfa dryer based on air-impingement jet and normal temperature ventilation was designed in current work. The alfalfa drying process was divided into 2 parts: high-temperature drying in air-impingement jet belt dryer based on the slit type air-impingement tube to improve the drying speed, and then drying at room temperature in the normal temperature ventilation apparatus to save energy. The slit type air-impingement tube is the main structure of air-impingement jet belt dryer. Flow field in slit type air-impingement tube was simulated using Fluent 14.0 CFD (computational fluid dynamics) software. The spoiler was added in this tube to improve the airflow uniformity of slit type nozzle exit. The location and height of spoiler are important influence factors of airflow uniformity. The structure of slit type air-impingement tube was optimized with the method of numerical simulation for flow field in which the spoiler had different parameters. The optimal parameter of spoiler was obtained, which then offered an optimum model that the variance coefficient of flow velocity was 7.7% through the 0.1-1.0 m section of nozzle exit. In order to collect information and realize automatic control, a single chip microcomputer system was designed for the room temperature ventilation apparatus. The PT100 and SHT11 sensors were used in the automatic control system to monitor the temperature and relative humidity of environment and grass. PIC16F1947 was used as the main control chip to control and dispose the information and control fan operation so as to solve the problem of moisture reabsorbtion of alfalfa in low temperature and high relative humidity environment. Alfalfa was adopted to test the performance of the normal temperature ventilation equipment combined with air-impingement jet. One group of experiment was that air-impingement jet belt dryer was used to dry alfalfa in different temperature and material thickness to the moisture content of about 45%-50%, and after that the material was dried at room temperature in the ventilation apparatus to the final moisture content of about 15%. It was observed that the moisture content of alfalfa with the thickness of 6 cm was reduced from 78.3% to 45% after 5 min drying. It can be concluded that air-impingement jet belt dryer has the ability of rapid drying for alfalfa even in high thickness. Additionally, the temperature of alfalfa was below 65℃ in the process of drying, which was beneficial to save thermal sensitive nutritions of alfalfa. The room temperature ventilation apparatus based on automation control could extensively reduce energy consumption of alfalfa drying. It can be concluded that the normal temperature ventilation dyer combined with hot air-impingement jet has the advantages of low-energy consumption and low leaf loss rate, as the leaf loss rate is less than 1.5%, and the energy consumption per kilogram moisture removal is 3408 kJ which is reduced by 53% compared with hot air drying. This paper exhibits a designed new equipment for alfalfa drying, the normal temperature ventilation dryer combined with air-impingement jet, which is very important to solve the problems of high energy consumption and high leaf loss rate of the current alfalfa drying equipment. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:29
Main heading:Air
Controlled terms:Automation - Computational fluid dynamics - Computer simulation - Dryers (equipment) - Drying - Energy conservation - Energy utilization - Equipment - Flow fields - Flow velocity - Humidity control - Moisture - Moisture determination - Nozzles - Numerical methods - Numerical models - Problem solving - Process control - Temperature - Thermal processing (foods) - Tubes (components) - Ventilation
Uncontrolled terms:Alfalfa - CFD (computational fluid dynamics) - Drying at room temperatures - High relative humidities - Impingement jet - Reduce energy consumption - Single chip microcomputers - Temperature and relative humidity
Classification code:525.2 Energy Conservation - 525.3 Energy Utilization - 619.1 Pipe, Piping and Pipelines - 631 Fluid Flow - 631.1 Fluid Flow, General - 641.1 Thermodynamics - 643.5 Ventilation - 723.5 Computer Applications - 731 Automatic Control Principles and Applications - 804 Chemical Products Generally - 822.2 Food Processing Operations - 901 Engineering Profession - 921 Mathematics - 921.6 Numerical Methods - 944.2 Moisture Measurements
Numerical data indexing:Energy 3.41e+06J, Percentage 1.50e+00%, Percentage 1.50e+01%, Percentage 4.50e+01% to 5.00e+01%, Percentage 5.30e+01%, Percentage 7.70e+00%, Percentage 7.83e+01% to 4.50e+01%, Size 1.00e-01m to 1.00e+00m, Size 6.00e-02m, Time 3.00e+02s
DOI:10.11975/j.issn.1002-6819.2017.15.037
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 27>
Accession number:20174204272510
Title:Effect of wind-sand erosion on frost resistance durability of hydraulic engineering concrete in cold irrigation area
Authors:Xue, Huijun (1); Shen, Xiangdong (1); Liu, Qian (1); Wang, Renyuan (1); Liu, Zheng (1); Han, Chao (1)
Author affiliation:(1) Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot; 010018, China
Corresponding author:Shen, Xiangdong(ndsxd@163.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:133-140
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In view of the actual situation of the concrete service environment of agricultural hydraulic engineering in the Yellow River irrigation of Inner Mongolia, due to the natural river sand becoming scarce, increasing the utilization efficiency of the local aeolian sand resources and using aeolian sand to form aeolian sand concrete meet the requirements of concrete in agricultural engineering and hydraulic engineering. The effect of wind-sand erosion on the frost resistance of aeolian sand concrete in cold irrigation area was studied. The replacement of natural river sand with the aeolian sand of quality substitution rates of 20%, 40% and 60% can be used to compose the aeolian sand concrete, the 28-day cube compressive strength of the aeolian sand concrete meets the C40 requirements. Using self-made sand-carrying flow erosion test device, the actual wind-sand environment in cold irrigation was simulated, including wind speed of 31 m/s, sand carrying capacity of 30 g/min, attack angle of 90° and erosion time of 10 min, and under these wind erosion parameters, the wind-sand erosion test of concrete was carried out. Two different test conditions were designed, i.e. the concrete frost resistance test and the concrete frost resistance test under the influence of wind-sand erosion. The mass loss rate and the relative dynamic modulus were used to evaluate the pros and cons of frost resistance test and the frost resistance test under the influence of wind-sand erosion, the super-depth three-dimensional topography of microscope was used to observe the concrete surface morphology under 2 different test conditions, and the bubble spacing device was used to test the bubble characteristic parameter of hardened aeolian sand concrete under 3 different substitution rates of aeolian sand. The results show that the quality loss rate can not accurately judge the effect of the freeze-thaw damage of aeolian sand concrete under the influence of wind-sand erosion, but the relative dynamic elastic modulus can accurately characterize the freeze-thaw damage of aeolian sand concrete under the influence of wind-sand erosion. Through the relative dynamic elastic modulus, it can be seen that the internal damage of aeolian sand concrete after freeze-thaw cycles under the influence of wind-sand erosion is 2 times that after freeze-thaw cycles without wind-sand erosion. Under the influence of wind-sand erosion, the aeolian sand concrete paste is crisped in the process of freeze-thaw cycles. At the same time, under the continuous impact of the wind-sand flow, the crisped cement paste peels off, and hence eventually the interface transition zone between cement paste and aggregate of destruction surface is more smooth. The aeolian sand with the quality substitution rate of 40% can be prepared to meet the requirement of frost resistance of aeolian sand concrete in cold irrigation area. The bubble spacing factor of hardened aeolian sand concrete can not accurately evaluate the frost resistance. The bubble box dimension and fine aggregate fineness modulus can reflect the bubble structure and fine aggregate grain gradation, and the two are associated and the combination of the two can be used to determine the durability of aeolian sand concrete. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:29
Main heading:Sand
Controlled terms:Aggregates - Agriculture - Cements - Compressive strength - Concretes - Durability - Elastic moduli - Erosion - Fluid mechanics - Freezing - Frost resistance - Hardening - Hydraulic structures - Hydraulics - Irrigation - Rivers - Shore protection - Surface morphology - Testing - Thawing - Wind
Uncontrolled terms:Aeolian sand - Box dimension - Bubble characteristics - Freeze-thaw cycles - Interface transition zones - Relative dynamic modulus - Three-dimensional topography - Utilization efficiency
Classification code:406 Highway Engineering - 407.1 Maritime Structures - 412 Concrete - 412.1 Cement - 443.1 Atmospheric Properties - 483.1 Soils and Soil Mechanics - 537.1 Heat Treatment Processes - 632.1 Hydraulics - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 821.3 Agricultural Methods - 931.1 Mechanics - 951 Materials Science
Numerical data indexing:Age 7.67e-02yr, Mass_Flow_Rate 5.00e-04kg/s, Percentage 2.00e+01%, Percentage 4.00e+01%, Percentage 6.00e+01%, Time 6.00e+02s, Velocity 3.10e+01m/s
DOI:10.11975/j.issn.1002-6819.2017.15.017
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 28>
Accession number:20174204272515
Title:Improving of soil physical and chemical properties and increasing spring maize yield by straw turnover plus nitrogen fertilizer
Authors:Bai, Wei (1); An, Jingwen (1); Zhang, Lizhen (2); Pang, Huancheng (3); Sun, Zhanxiang (1); Niu, Shiwei (1); Cai, Qian (1)
Author affiliation:(1) Tillage and Cultivation Research Institute, Liaoning Academy of Agricultural Sciences, Shenyang; 110161, China; (2) College of Resources and Environmental Sciences, China Agricultural University, Beijing; 100193, China; (3) Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing; 100081, China
Corresponding author:An, Jingwen(jingwenan@126.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:168-176
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Improving plough layer is necessary for solving the problems of shallow and compacted plough layer and plough layer lack, which are caused by a long-term unreasonable tillage. In order to examine the effects of straw turnover and different nitrogen (N) additions to plough layer on the yield, soil physical properties, root morphology of spring maize in dry land, 6 treatments were conducted in Tieling of Liaoning Province from 2014 to 2015. The 6 treatments included straw turnover of 0 kg/hm<sup>2</sup>and adding pure N of 0 kg/hm<sup>2</sup>(S0F0), straw turnover of 9 000 kg/hm<sup>2</sup>and adding pure N of 0 kg/hm<sup>2</sup>(SN0), straw turnover of 9 000 kg/hm<sup>2</sup>and adding pure N of 112.5 kg/hm<sup>2</sup>(SN1), straw turnover of 0 kg/hm<sup>2</sup>and adding pure N of 225 kg/hm<sup>2</sup>(S0N2) (local traditional cropping pattern, CK), straw turnover of 9000 kg/hm<sup>2</sup>and adding pure N of 225 kg/hm<sup>2</sup>(SN2), straw turnover of 9 000 kg/hm<sup>2</sup>and adding pure N of 337.5 kg/hm<sup>2</sup>(SN3). The result showed that treatments of straw turnover and different N additions significantly influenced spring maize yields, soil physical properties and root morphology. The treatment of straw turnover of 9 000 kg/hm<sup>2</sup>and N addition of 225 kg/hm<sup>2</sup>had the highest yield, increasing by 1.10%-11.56% compared with none straw turnover. This increase in yield of spring maize was mainly contributed by the augmented 100-grain weight and grain number, as well as the decreased bald tip. The N addition did not promote the yield while improved the biomass of whole crop. On the same level of N addition, the spring maize yield of straw turnover treatment was 3.08%-3.56% higher than that of none straw turnover treatment, whereas the harvest index of straw turnover treatment was 2.43%-3.12% lower than that of none straw turnover treatment. Plough layer construction of straw turnover and N addition could significantly lower soil bulk density, especially in soil depth of 15-20 cm. Treatment of straw turnover plus N fertilizer to plough layer construction could also loosen top soil, and further enhance rainwater infiltration and soil water content, whereas the similar trend did not be observed for the treatment of N addition. The soil three-phase structure derived from SN2 treatment was the optimum, with 25% liquid phase, 25% gas phase and 50% solid phase, respectively. The root indices, including amount, length, volume and dry weight of root of spring maize, were better than the indices of none straw turnover treatment. On the same level of N addition, the amount, length, volume and dry weight of root of spring maize were 1.90%, 10.27%, 1.25% and 2.77% higher than the corresponding index of treatment of none straw turnover, respectively. Consequently, we suggest that the treatment of straw turnover of 9 000 kg/hm<sup>2</sup>and N addition of 225 kg/hm<sup>2</sup>is the optimum approach of plough layer construction and technology of straw turnover in the brown soil area of northern Liaoning Province, which is recommended to be applied in agricultural production. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:35
Main heading:Soils
Controlled terms:Agricultural machinery - Agriculture - Fertilizers - Morphology - Nitrogen - Nitrogen fertilizers - Phase structure - Physical properties - Soil moisture - Straw
Uncontrolled terms:Agricultural productions - Nitrogen additions - Rainwater infiltrations - Root morphology - Soil physical and chemical properties - Soil physical property - Soil water content - Spring maize
Classification code:483.1 Soils and Soil Mechanics - 804 Chemical Products Generally - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 931.2 Physical Properties of Gases, Liquids and Solids
Numerical data indexing:Percentage 1.03e+01%, Percentage 1.10e+00% to 1.16e+01%, Percentage 1.25e+00%, Percentage 1.90e+00%, Percentage 2.43e+00% to 3.12e+00%, Percentage 2.50e+01%, Percentage 2.77e+00%, Percentage 3.08e+00% to 3.56e+00%, Percentage 5.00e+01%, Size 1.50e-01m to 2.00e-01m
DOI:10.11975/j.issn.1002-6819.2017.15.022
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 29>
Accession number:20174204272494
Title:Yield and physical characteristics analysis of domestic waste in rural areas of China and its disposal proposal
Authors:Han, Zhiyong (1, 2, 3); Fei, Yongqiang (1, 2); Liu, Dan (4); Dan, Zeng (5); Zhang, Yu (1, 2); Shi, Guozhong (3); Wang, Jialei (6); Xie, Yanhua (1, 2)
Author affiliation:(1) State Key Laboratory of Geohazard Prevention and Geoenvironment Protection (Chengdu University of Technology), Chengdu; 610059, China; (2) State Environmental Protection Key Laboratory of Synergetic Control and Joint Remediation for Soil & Water Pollution (Chengdu University of Technology), Chengdu; 610059, China; (3) Biogas Institute of Ministry of Agriculture, Chengdu; 610041, China; (4) Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu; 610031, China; (5) Science School of Tibet University, Lhasa; 850002, China; (6) China Urban Construction Design & Research Institute Co. Ltd., Beijing; 100120, China
Corresponding author:Shi, Guozhong(shiguozhong@caas.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:1-14
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In recent decades, a huge accumulation of domestic waste has caused serious environmental contamination, including negative impacts on human health in rural areas of China. Generally, collection, transport, treatment and disposal of waste are usually considered as the most important stages of waste management, which are directly linked to waste generation and characteristics. So, it is difficult to optimize the design of the required infrastructures and facilities without an accurate estimation of the amounts and characteristics of domestic waste. Nevertheless, to date few studies have investigated the characteristics of domestic waste in the rural areas of China. The main purpose of our work is to provide reliable background information as a reference and guidance for the source classification, for recycling, and for the treatment and disposal of domestic waste in rural areas of China. A total of 580 households in 59 villages of 6 provinces in West China were surveyed and 128 questionnaires were reviewed, based on which, the generation and physical characteristics of domestic waste in rural areas of China were analyzed via statistic method and the comparisons between different regions, between urban and rural areas and between China and other countries. Results showed that the sources of domestic waste in rural areas of China mainly included catering, daily consumption (such as packages, residues and obsoleted daily goods), cleaning from public areas and agricultural production. The generation rate of rural domestic waste was 0.034-3.000 kg/d per capita in different regions with the median of 0.521 kg/d per capita. It is much lower than the generation rate in cities and other developed countries. The total generation reached up to 148 million tons in 2014 in rural areas of China. The rural domestic waste showed the characteristics of wide range of sources, low generation rate, high volume, good compressibility, rapid growth and significant regional differences. Rural domestic waste was mainly composed of kitchen waste, ash, plastics and rubbers and paper with a cumulative proportion of 83.61%. The composition of the rural domestic waste differed significantly from regions. The content of plastic/rubber gradually decreased from south to north in China; on the contrary, the ash waste increased. In recent decades, the contents of kitchen waste, paper, plastic/rubber increased with time but the contents of ash waste, brick/ceramic, wood and glass decreased. It is because the composition of domestic waste in the countryside was gradually becoming similar with that of municipal solid waste in the city. However, it still had lower contents of kitchen waste and metals while higher content of ash waste compared with those in cities. The bulk density of the domestic waste was 40-650 kg/m<sup>3</sup>with an average of 263 kg/m<sup>3</sup>. Moreover, the compressibility of the RDW was very good. Based on the outcome of this research, compressed garbage trucks and transfer stations are suggested in the countryside where the centralized treatment and disposal in the local county has been developed. Furthermore, sorting collection is recommended to separate kitchen waste and ash at the source and then treat them on site. These recommendations can greatly relieve the loads of waste collection, transportation and disposal and ensure financial viability. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:128
Main heading:Municipal solid waste
Controlled terms:Agriculture - Classification (of information) - Compressibility - Garbage trucks - Kitchens - Physical properties - Rural areas - Surveys - Waste disposal - Waste management - Waste treatment - Wastes
Uncontrolled terms:Agricultural productions - Background information - Bulk density - Environmental contamination - Physical characteristics - Treatment and disposal - Urban and rural areas - Waste composition
Classification code:452 Municipal and Industrial Wastes; Waste Treatment and Disposal - 452.4 Industrial Wastes Treatment and Disposal - 716.1 Information Theory and Signal Processing - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 931.2 Physical Properties of Gases, Liquids and Solids - 951 Materials Science
Numerical data indexing:Mass_Density 2.63e+02kg/m3, Mass_Density 4.00e+01kg/m3 to 6.50e+02kg/m3, Percentage 8.36e+01%
DOI:10.11975/j.issn.1002-6819.2017.15.001
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 30>
Accession number:20174204272509
Title:Changes of matric suction in expansive soil under drying-wetting cycles using filter paper method
Authors:Wu, Junhua (1, 2); Yang, Song (3)
Author affiliation:(1) Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University, Nanchang; 330063, China; (2) College of Civil Engineering and Architecture, Nanchang Hangkong University, Nanchang; 330063, China; (3) College of Water Conservancy, Yunnan Agricultural University, Kunming; 650201, China
Corresponding author:Yang, Song(yscliff007@126.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:126-132
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Soil water characteristic curve (SWCC) can show the soil water holding capacity, and is the relationship between the soil matric potential and saturation. The expansive soil has the characteristics of strong swell-shrink, developing fissures and over consolidation, especially under drying-wetting cycles. Its water holding capacity, which has an important impact on the soil properties, is totally different from the capacity of full soil. Therefore, how to exactly obtain the matric suction of expansive soil under drying-wetting cycles is very important to analyze the characteristics of mechanics and deformation of expansive soil. In order to analyze the change rule of matric suction of expansive soil under drying-wetting cycles, the artificial rainfall and evaporation was applied in drying-wetting tests of expansive soil. The specimens sized at 102 mm × 40 mm (diameter × height) were made by compaction apparatus and the initial dry density was 1.68 g/cm<sup>3</sup>. All the specimens were saturated after compaction and undergoing drying-wetting cycles in constant temperature (22℃) environment. The small electric fans were adopted to increase the rate of evaporation until the mass of specimens was kept constant under the condition of drying. Then the water vapours were sprayed to the surface of specimens by humidifiers until the process of infiltration stopped under the condition of wetting. That is one drying-wetting cycle so far. In this paper, 4 set of experiments under drying-wetting cycles were carried out and the cycle times were 1, 2, 3 and 4 respectively. Then 11 specimens sampled by cutting rings (61.8 mm × 20 mm (diameter × height)) in different volumetric water content were obtained in each process of drying and wetting respectively. The matric suction of each specimen was measured with filter paper of Whatman No. 42 and then the SWCCs were obtained under drying-wetting cycles. The corresponding air-entry values and residual values in different drying-wetting cycle times were calculated from SWCC. Ulteriorly, the different SWCCs obtained in different drying-wetting cycle times were fitted by the Fredlund SWCC model. Based on the above analysis, an SWCC model of expansive soil considering drying-wetting cycle effect was established finally. The results showed that: 1) With the increase of drying-wetting cycle time, the air-entry value of expansive soil was evidently reduced. Compared with the air-entry value (134.5 kPa) of expansive soil undergoing one drying-wetting cycle, the air-entry value was 58.5 kPa and reduced by 56.5% undergoing 4 drying-wetting cycles. The most effect of drying-wetting cycles on air-entry value occurred in the first cycle. 2) With the increase of drying-wetting cycle time, the residual value of expansive soil was also reduced. Compared with the residual value (1 040.5 kPa) of expansive soil undergoing one drying-wetting cycle, the residual value was 528.5 kPa and reduced by 49.2% undergoing 4 drying-wetting cycles. Moreover, the residual value is reduced evidently after undergoing one drying-wetting cycle and it cannot yet be stabilized with the increase of drying-wetting cycle time. That means the effect of drying-wetting cycles on ari-entry value is much greater than on residual value. 3) The fitted parameters in the SWCC model of expansive soil considering the effect of drying-wetting cycle have a good linear correlation with the drying-wetting cycle time. With the increase of drying-wetting cycle time, the soil air-entry value and change rate of water content reduce while the residual value increases gradually. The results can provide a reference for the further analysis on soil matric suction and its application in engineering. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:30
Main heading:Wetting
Controlled terms:Bandpass filters - Compaction - Cracks - Drying - Evaporation - Soil moisture - Soil testing - Soils - Water content
Uncontrolled terms:Drying-wetting cycle - Expansive soils - Filter paper method - Matric suctions - Soil-water characteristic curve
Classification code:483.1 Soils and Soil Mechanics - 703.2 Electric Filters - 802.3 Chemical Operations
Numerical data indexing:Mass_Density 1.68e+03kg/m3, Percentage 4.92e+01%, Percentage 5.65e+01%, Pressure 1.34e+05Pa, Pressure 4.05e+04Pa, Pressure 5.28e+05Pa, Pressure 5.85e+04Pa, Size 2.00e-02m, Size 4.00e-02m
DOI:10.11975/j.issn.1002-6819.2017.15.016
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 31>
Accession number:20174204272497
Title:Optimal design and experiment of hybrid-driven five-bar flower potted-seedling transplanting mechanism
Authors:Zhao, Xiong (1); Cui, Haiyang (1); Dai, Li (1); Xu, Yadan (1, 2); Wang, Chuan (1); Shen, Jin (1)
Author affiliation:(1) College of Mechanical Engineering and Automation, Zhejiang Sci-Tech University, Hangzhou; 310018, China; (2) College of Qingnian Automotive, Hangzhou Vocational and Technical College, Hangzhou; 310018, China
Corresponding author:Dai, Li(daili@zstu.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:34-40
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Flower potted-seedling transplanter is usually a complex system of cylinder, hydraulic rod and electromagnetic valve, and its high price brings impediment for its promotion. Utilizing a single mechanism to achieve the kinematics requirement of seedling transplanting can be very difficult. Hybrid-driven mechanism can not only have the high transmission efficiency and carrying capacity as the single degree-of-freedom mechanism, but can also have the high flexible degree as the multi degree-of-freedom mechanism. Aiming at simplifying the potted-seedling transplanting mechanism and adding the flexibility of kinematic design, a hybrid-driven five-bar mechanism was proposed to realize the flower potted-seedling transplanting. The trajectory of the mechanism was proposed according to the work requirements and a mathematical model of hybrid-driven five-bar flower potted-seedling transplanting mechanism was built. Aiming at the minimum angular velocity fluctuation of the variable speed motor, the parameters of the mechanism were optimized through genetic algorithm toolbox of MATLAB. The rack location of mechanism was set as (0, -150) and (-267.20, 61.87) based on the optimization results of genetic algorithm. The bar lengths of five-bar mechanism were 152.80, 324.55, 336.56, 100.40, 302.60 and 341.00 mm. A three-dimensional model of flower potted-seedling transplanting mechanism was built, the kinematic simulation of mechanism was carried out by ADAMS software, and the correctness of the mechanism's optimization results was verified through kinematic simulation. A control system of the hybrid-driven five-bar flower potted-seedling transplanting mechanism was designed and the position mode of servo motor was adopted in order to achieve the precise position control required by the mechanism. Meanwhile, the design of the control system realized the requirements of synchronous control and real-time match control in flower potted-seedling transplanting mechanism. The structures of the five-bar mechanism and transplanting arm mechanism were designed and the parts of these mechanisms were machined, and then a prototype was assembled to carry out the experiment research of flower potted-seedling transplanting. Through the experiment, the height of flower transplanting trajectory was measured as 265 mm. When the transplanting claw was picking up the potted-seedling, the azimuth angle was 140°, the swinging angle was 6.92° in the process of claw entering the potted-seedling, the swinging angle was 6.27° in the process of claw leaving the potted-seedling, and the width of buckle was less than 3 mm. When the transplanting claw was planting the potted-seedling, the azimuth angle was 90°, the swinging angle was 13.19° in the process of claw entering the potted-seedling, the swinging angle was 4.19° in the process of claw leaving the potted-seedling, and the vertical trajectory height was longer than 40 mm. The average successful rate of 5 transplanting experiments was 87.16% which indicated that hybrid-driven five-bar flower potted-seedling transplanting mechanism can realize the flower potted-seedling transplanting work. Meanwhile, the upright degree and success rate of picking up and planting the flower potted-seedling were ensured in the process of transplanting work. The application field of hybrid drive is extended in this article and a new choice for the design of automatic flower potted-seedling transplanting equipment is provided as well. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:25
Main heading:Mechanisms
Controlled terms:Agricultural machinery - Atmospheric movements - Bars (metal) - Computer software - Control systems - Degrees of freedom (mechanics) - Design - Genetic algorithms - Hydraulic machinery - Kinematics - Machine design - MATLAB - Optimization - Position control - Trajectories - Ultrasonic devices
Uncontrolled terms:Hybrid drive - Hybrid-driven mechanism - Multi degree-of-freedom - Parallel mechanisms - Reverse solution - Seedling transplanting - Single degree of freedoms - Three-dimensional model
Classification code:443.1 Atmospheric Properties - 535.1.2 Rolling Mill Practice - 601 Mechanical Design - 601.3 Mechanisms - 632.2 Hydraulic Equipment and Machinery - 723 Computer Software, Data Handling and Applications - 731.1 Control Systems - 731.3 Specific Variables Control - 753.2 Ultrasonic Devices - 821.1 Agricultural Machinery and Equipment - 921 Mathematics - 921.5 Optimization Techniques - 931.1 Mechanics
Numerical data indexing:Percentage 8.72e+01%, Size 2.65e-01m, Size 3.00e-03m, Size 3.03e-01m, Size 3.41e-01m, Size 4.00e-02m
DOI:10.11975/j.issn.1002-6819.2017.15.004
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 32>
Accession number:20174204272522
Title:Information integration management system for spiral bevel gear networked manufacturing process
Authors:Li, Jubo (1, 2); Gao, Zhenshan (1, 2); Li, Tianxing (1, 2); Yang, Jianjun (1, 2); Xu, Aijun (1, 2); Wang, Bin (1, 2)
Author affiliation:(1) School of Mechatronics Engineering, Henan University of Science and Technology, Luoyang; 471003, China; (2) Collaborative Innovation Center of Machinery Equipment Advanced Manufacturing of Henan Province, Luoyang; 471003, China
Corresponding author:Gao, Zhenshan(lygaozhenshan@163.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:227-236
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In order to more effectively support the information interaction and integration operation in spiral bevel gears networked manufacturing process, and implement the integrated management and control of manufacturing information data, we combined the characteristics of spiral bevel gears manufacturing process and information integration with management technologies, and proposed an architecture of information integration management system for spiral bevel gears networked manufacturing process in this paper based on the hierarchical thoughts. The architecture consisted of the access layer, management layer, information layer, activity layer, and resource layer which were integrated to form a whole information management system to realize the effective management and integration of entire manufacturing process form the initial spiral bevel gear orders to the final products delivery. Based on this and from the system overall operation perspective, the integration operation mode for spiral bevel gears networked manufacturing was established. Subsequently, according to the integration and sharing requirement of various information resources, the information description and integration framework of spiral bevel gear networked manufacturing process was set up based on the XML (extensible markup language) and Web service technologies, and the XML description, and Web service encapsulation mechanism of various information resources in spiral bevel gears networked manufacturing process were researched. Through making the XML Schema as the data exchange specification, the standard structures of manufacturing process information data were specifically defined, which mainly included the content, format, and attributes. According to the XML Schema standard specification definition, the XML document mapping conversion and Web service encapsulation of manufacturing process information data were finally achieved. Afterwards, by means of the Web service application integration mechanism, the information description and integration of whole spiral bevel gear networked manufacturing process was realized. Based on the service oriented architecture, the loosely-coupled and openness function model of information integration management system was built, which was divided into the application layer, interface layer, business layer, service layer, and system layer. Meanwhile, the information management and Web service called mechanism of entire function model, as well as the role of each layer and the logical relationship between the layers were elaborated. In Windows 2003 Enterprise Server, Microsoft Visual Basic.NET, and SQL Server 2005 development environment, and based on Browser/Server architecture pattern, the prototype system as well as the all corresponding function service and management interfaces of information integration management system were planned and developed. The information integration and unified management of entire spiral bevel gears networked manufacturing process were realized, which formed the gear order receipt, project planning, design and calculation of gears, process programming, task scheduling, procedure machining to the product delivery. Finally, through the enterprise application experiment of spiral bevel gears networked manufacturing, the validity of information integration management system in improving the production and management efficiency, shortening the gear production cycle, reducing the production costs were verified. Actual application results showed that the proposed architecture and implementation method of information integration management system were feasible and practical. It can effectively improve the operation and management efficiency of whole spiral bevel gears networked manufacturing process. Taking the networked manufacturing process of spiral bevel gear orders in this paper as an example, in the whole enterprise application test process, we compared with the traditional distributed manufacturing and information management mode. The productivity of application enterprise was increased about 8%, the management efficiency was improved around 25%, and the production costs were reduced more than 3%. This research presents an effective method for realizing the informatization and integration of spiral bevel gears networked manufacturing process. It may also provide a reference for the further research and application implementation of spiral bevel gears networked manufacturing mode. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:32
Main heading:Information management
Controlled terms:Architecture - Bevel gears - Computer aided manufacturing - Computer architecture - Cost reduction - Data encapsulation - Efficiency - Electronic data interchange - Electronic document exchange - Gear manufacture - Gears - Hypertext systems - Industrial research - Information analysis - Information retrieval - Information services - Integral equations - Manufacture - Networked control systems - Product design - Project management - Scheduling - Service oriented architecture (SOA) - Specifications - Testing - Web services - Websites - Windows operating system - XML
Uncontrolled terms:Browser/server architectures - Distributed manufacturing - Information integration - Information management systems - Integrated management and controls - Management systems - Manufacturing informations - XML (extensible markup language)
Classification code:402 Buildings and Towers - 601.2 Machine Components - 722.4 Digital Computers and Systems - 723 Computer Software, Data Handling and Applications - 731.1 Control Systems - 902.2 Codes and Standards - 903 Information Science - 912.1 Industrial Engineering - 912.2 Management - 913.1 Production Engineering - 913.4 Manufacturing - 921.2 Calculus
Numerical data indexing:Percentage 2.50e+01%, Percentage 3.00e+00%, Percentage 8.00e+00%
DOI:10.11975/j.issn.1002-6819.2017.15.029
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 33>
Accession number:20174204272523
Title:Design and implementation on real-time monitoring system of laying hens environmental comfort based on LabVIEW
Authors:Bai, Shibao (1, 4); Teng, Guanghui (1, 2, 3); Du, Xiaodong (1, 2, 3); Du, Xinyi (1, 2, 3)
Author affiliation:(1) Key Lab of Agricultural Engineering in Structure and Environment, Ministry of Agriculture, Beijing; 100083, China; (2) College of Water Conservancy and Civil Engineering, China Agricultural University, Beijing; 100083, China; (3) Beijing Engineering Research Center on Animal Healthy Environment, Beijing; 100083, China; (4) Big Herdsman Machinery Co., LTD, Qingdao; 266108, China
Corresponding author:Teng, Guanghui(futong@cau.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:237-244
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Living in a comfortable environment during the period of egg production will enable laying hens to achieve their genetic potential. With the development of the poultry industry to larger scale, the air quality in laying house has become the most important factor affecting the health level and production performance of laying hens. Because of the complexity of environmental factors, such as temperature, relative humidity, wind speed, and concentration of CO<inf>2</inf>and NH<inf>3</inf>, it is difficult to describe the level of the environmental comfort quantitatively. In this study, the real-time system of monitoring environment comfort for laying hens was established by the following methods. Firstly, the comfort thresholds of temperature, relative humidity, wind speed, and concentration of CO<inf>2</inf>and NH<inf>3</inf>for laying hens were established respectively by investigating relevant references. The results showed that the temperatures for comfortable zone (CZ), less comfortable zone (LCZ) and uncomfortable zone (UZ) were 18-21℃, 13-18 or 21-26℃, and <5℃ or >30℃ respectively. As for the RH, the temperatures for these 3 zones were 60%-70%, 40%-60% or 70%-72%, and <40% or >72% respectively. The ranges of wind speed for CZ, LCZ and UZ in winter were 0.1-0.2 m/s, 0-0.1 or 0.2-0.25 m/s and >0.25 m/s respectively, and in summer were 0.5-1.5 m/s, 0.25-0.5 or 1.5-2.5 m/s and <0.25 or >2.5 m/s respectively. And the concentrations of CO2 for these 3 zones were <1 500, 1 500-4 000, and >4 000 mg/m3 respectively; the concentrations of NH<inf>3</inf>were <15, 15-20, and >25 mg/m<sup>3</sup>, respectively. Secondly, the theory of fuzzy comprehensive evaluation was used for data fusion of the environment factors, and AHP (analytic hierarchy process) was applied to determine the weight of the environment factors in winter and summer. The results showed that the weight set of temperature, relative humidity, wind speed, concentration of CO<inf>2</inf>and NH<inf>3</inf>in winter was 0.428 6, 0.151 1, 0.049 5, 0.282 8, and 0.087 9, respectively, and in summer was 0.432 6, 0.241 8, 0.102 9, 0.081 3, and 0.141 4, respectively. Thirdly, a real-time data collection and analysis system of laying house environment was built through the LabVIEW platform, and the real-time environmental comfort evaluation was presented in this system. Lastly, a new method named comfort time proportion method was developed to collect the statistic data of environmental comfort during feeding period. On the basis of the platform of Agricultural Internet constructed by Key Laboratory of Agriculture Engineering in Structure and Environment, Ministry of Agriculture, the laying houses in the Huangshan Deqingyuan Poultry company and in the Shangzhuang Experimental Station of China Agricultural University were selected as the environmental data acquisition node, and then the real-time monitoring system of environmental comfort for laying hens was tested and verified. Compared with the single environment factor, the system can reflect the environmental comfort of the house more comprehensively. And the environment comfort of the laying house in Deqingyuan was better than that in Shangzhuang Experimental Station in winter. The outcomes of this paper will be helpful for evaluating the environment comfort for laying hens. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:29
Main heading:Monitoring
Controlled terms:Agriculture - Air quality - Atmospheric humidity - Carbon dioxide - Data acquisition - Data fusion - Houses - Interactive computer systems - Internet of things - Real time systems - Temperature - Wind
Uncontrolled terms:AHP (analytic hierarchy process) - Design and implementations - Environmental comfort - Fuzzy comprehensive evaluation - LabViEW - Laying hens - Real time data collections - Real time monitoring system
Classification code:402.3 Residences - 443.1 Atmospheric Properties - 451.2 Air Pollution Control - 641.1 Thermodynamics - 722.4 Digital Computers and Systems - 723 Computer Software, Data Handling and Applications - 723.2 Data Processing and Image Processing - 804.2 Inorganic Compounds - 821 Agricultural Equipment and Methods; Vegetation and Pest Control
Numerical data indexing:Percentage 6.00e+01% to 7.00e+01%, Percentage 7.00e+01% to 7.20e+01%, Velocity 1.00e-01m/s to 2.00e-01m/s, Velocity 1.50e+00m/s to 2.50e+00m/s, Velocity 2.00e-01m/s to 2.50e-01m/s, Velocity 5.00e-01m/s to 1.50e+00m/s
DOI:10.11975/j.issn.1002-6819.2017.15.030
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 34>
Accession number:20174204272517
Title:Improving effect of hydraulic characteristics of nature-like fishway with pools and cobblestone weirs
Authors:Li, Guangning (1); Sun, Shuangke (1); Liu, Haitao (1); Zhang, Chao (1); Zhao, Guixia (2); Zheng, Tiegang (1)
Author affiliation:(1) State Key Laboratory of Simulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing; 100038, China; (2) State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin; 300072, China
Corresponding author:Sun, Shuangke(sunshuangke@126.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:184-189
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The nature-like fish way is one of the most promising layouts of fish pass structures, its remarkable characteristics are that the individual cobblestone weirs from local river bed substrates are adopted in the fishway construction to imitate as closely as possible the flow pattern of Natural River. Therefore it has higher running efficiency for fish migration than traditional technical fishways. In order to identify the differences of the hydraulic characteristics between the nature-like fishway and the traditional fishway, we conducted comparative studies. The three-dimensional mathematical models of the fishways with cobblestone weirs and water proof weirs were developed respectively. The cobblestone weirs had porosity about 12%. It was defined as the ratio of pervious area to total area of the vertical section along with the longitudinal direction. Each mathematical cobblestone feature was defined as obstacles with special shapes as the natural one. The gaps between the cobblestones allowed water to pass through existing calculation elements. A hydraulic model of the fishway with cobblestone weirs was designed based on the law of gravity similarity at a scale of 1: 5. The fishway structure of the model test was consistent with the mathematical model. The water depth and velocity at typical measurement points were recorded. The results were used to verify the numerical model. In the scenario that the fish way upstream and downstream water depth was 1.4 m, the hydraulic characteristics in the fish ways, such as flow pattern, flow velocity, turbulence kinetic energy, and flow rate were compared. The results showed that the currents coming from the cobblestone gaps improved the flow dynamics conditions in the pools. The velocity distributions of the gaps in the staggered weirs appeared as the velocities of the surface were smaller than the bottom; the velocities of the sides were smaller than that of the middle. Obviously, using permeable weir fishway, the abundance of velocity distribution for fish was quite obvious, and the velocity distribution of impervious weir fishway was close to uniform. Turbulence in the mainstream can attract fish back to migration, the turbulence kinetic energy (TKE) was considered as a potential index to assess the suitability of the fishway structure. The turbulent intensity preferred by fish may depend on their swimming capabilities. In the fishways with cobblestone weirs, the TKE had greatly increased; the TKE on the surface was higher than that near the bottom. As the water surface of each of the pool was kept at the same level, the water consumption flow is very different between the impervious weir and cobblestone weir fishway. The consumption flow of the impervious weir fishway was Q=1.39 m<sup>3</sup>/s, while the consumption flow of the cobblestone weir fishway was Q=2.86 m<sup>3</sup>/s, which was increased to about twice. Thus, the nature-like fishways with cobblestone weirs needed more water flow in operating. The flow pattern of the nature-like fishway was rich and varied, and it was closer to the natural river; environment. As such it provided abundant hydrodynamic conditions for different types of migration fish. The effecting factors on the hydraulic characteristics of the nature-like fishway were analyzed, such as partition type, bottom slope, and different operation depth and so on. In general, the simulation technique of nature-like fishway was still at the exploratory stage, and the study should be further developed with a consideration with special life habits of migratory fish. The approach used in this paper can provide reference for the hydraulic design and optimization of nature-like fishway. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:31
Main heading:Rivers
Controlled terms:Buoyancy - Computer simulation - Fish - Fisheries - Fishways - Flow of water - Flow patterns - Flow rate - Flow velocity - Hydraulic models - Hydraulic structures - Kinetic energy - Kinetics - Lakes - Numerical models - Turbulence - Velocity - Velocity distribution - Weirs
Uncontrolled terms:Consumption flow - Hydraulic characteristic - Hydrodynamic conditions - Longitudinal direction - Simulation technique - Three-dimensional mathematical models - Turbulence kinetic energy - Turbulent intensities
Classification code:441.1 Dams - 631 Fluid Flow - 632.1 Hydraulics - 723.5 Computer Applications - 921 Mathematics - 922.2 Mathematical Statistics - 931.2 Physical Properties of Gases, Liquids and Solids
Numerical data indexing:Percentage 1.20e+01%, Size 1.40e+00m
DOI:10.11975/j.issn.1002-6819.2017.15.024
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 35>
Accession number:20174204272513
Title:Slope instability evaluation method using finite element method of strength reduction and displacement rate
Authors:Jiang, Shenghua (1); Wang, Shiji (1); Li, Weiqing (1); Bao, Anhong (1)
Author affiliation:(1) College of Engineering and Technology, Southwest University, Chongqing; 400715, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:155-161
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Finite element method of strength reduction is an important and effective measure to evaluate the stability safety of geotechnical engineering. Also, finite element method of strength reduction is widely used in slope stability computation, and failure criterion using deformation has obvious significance in aspects of physical and engineering meaning. However, there is no consensus among researchers regarding location selection of critical points, step-size of strength reduction, determination from horizontal displacement, vertical displacement and total displacement. Also, there is no consensus with regard to how to judge the limit state of slope when there is no obvious knee point on the curve of displacement versus strength reduction factor. The strength reduction of variable step-size is proposed in the paper. The curves of displacement, displacement rate versus strength reduction factor, are calculated automatically with the main program of Fortran and subroutine program of ANSYS software. The knee point on curve of displacement rate versus strength reduction factor is chosen as the failure criterion, and the sensitivity and location range of critical points are also studied. When strength reduction factor is 1.42, there is definite and specific knee point on curve of horizontal displacement rate, vertical displacement rate and total displacement rate of slope top versus strength reduction factor, which shows displacement rate is more accurate and sensitive than displacement in terms of slope failure criterion. When the critical point is in the vicinity of slope top and it is not located in plastic zone or sliding soil mass, there is also abrupt turning on the curve of displacement rate versus strength reduction factor with oscillation phenomenon although the critical points are relatively far from the slope point; and the corresponding safety factor is also about 1.42. Eighteen critical points are selected from different locations of slope, and by means of curves of horizontal displacement rate, vertical displacement rate and total displacement rate versus strength reduction factor, 54 safety factors are obtained. Consequently, the mean value of 54 safety factors is 1.420 and the variation coefficient is 0.005 3, which show that different critical points have nearly same safety factors and there is little difference between safety factors judged by horizontal displacement rate, vertical displacement rate or total displacement rate. When the distance from critical point to slope top is smaller than 20 m, about the height of slope, the total displacement of critical point is larger than 12 mm and the total displacement rate is large, which indicate that the critical points have high sensitivity. When the distance from critical point to slope top is larger than slope height, the total displacement of critical point ranges from 5 to 18 mm but the total displacement rate decreases drastically, which show that the critical points are also not sensitive either. Considering the influence of boundary range and the critical points' sensitivity, it is suggested that the distance from the critical points to slope top should be less than the slope height. The step-size of strength reduction should be decreased gradually and small step-size should be used when the slope deformation is close to instable sliding. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:30
Main heading:Finite element method
Controlled terms:Boundary conditions - Deformation - Failure (mechanical) - Geotechnical engineering - Location - Models - Safety engineering - Safety factor - Slope stability - Stability - Subroutines
Uncontrolled terms:Displacement rate - Horizontal displacements - Oscillation phenomenon - Slope stability computations - Strength reduction factors - Strength reduction method - Variation coefficient - Vertical displacements
Classification code:406.2 Roads and Streets - 409 Civil Engineering, General - 481 Geology and Geophysics - 723.1 Computer Programming - 914 Safety Engineering - 914.1 Accidents and Accident Prevention - 921.6 Numerical Methods
Numerical data indexing:Size 1.20e-02m, Size 2.00e+01m, Size 5.00e-03m to 1.80e-02m
DOI:10.11975/j.issn.1002-6819.2017.15.020
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 36>
Accession number:20174204272496
Title:Development of 2ZXM-2 automatic plastic film mulching plug seedling transplanter for vegetable
Authors:Li, Hua (1, 2); Cao, Weibin (1); Li, Shufeng (1); Liu, Jiaodi (1); Chen, Bangbang (1); Ma, Xiaoxiao (1)
Author affiliation:(1) College of Mechanical and Electrical Engineering, Shihezi University, Shihezi; 832003, China; (2) The State Key Laboratory of Mechanical Transmissions, Chongqing University, Chongqing; 400044, China
Corresponding author:Cao, Weibin(Wbc828@163.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:23-33
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Xinjiang has the adequate light and large temperature difference between day and night, and its unique light and heat resources are very suitable for crop growing, such as tomato and pepper; the planting area and productivity of Xinjiang have been ranked the first in China for many years. But due to special climatic conditions in Xinjiang area, crops are generally transplanted on the plastic film, and also need to lay a drip belt. In recent years, Xinjiang has begun to vigorously promote the crop transplanting technology, and the transplanting area of tomato and pepper has continued to increase. However, at present, there are no automatic vegetable transplanting machines available in Xinjiang, and the seedlings transplanting work basically relies on manual operation; some transplanters used are mainly semi-automatic machines, which still need manual work to pick up seedlings and drop seedlings, and also need laying the film and drip irrigation before transplanting, as well as the additional press and soil covering operations after the transplanting. Therefore, it is very important and urgent to study the multi-functional automatic transplanter for plug seedling in Xinjiang. In this paper, the 2ZXM-2 automatic plastic film mulch plug seedling transplanter for tomato and pepper was developed to replace the manual operation and semi-automatic machines transplanting. The mechanism mainly consisted of the frame, the laying film device, the soil covering and pressing mechanism, the automatic seedling pick-up mechanism, the planting mechanism and the automatic seedling feeding system which can feeding seedlings accurately for the pick-up mechanism. The transplanter designed not only can complete automatic seedling transplanting and soil covering and pressing at one time, it can also lay drip irrigation belt and plastic film at the same time. With the 2ZXM-2 automatic plastic film mulch plug seedling transplanter, it is very convenient to complete the multi-channel working procedure of transplanting, and it can also be applied to the transplanting of different crops. In order to verify the performance of automatic transplanter, the test prototype was made and the pepper field transplant experiment was carried out in the Key Laboratory for Xinjiang Production and Construction Corps Agricultural Machinery. The test results showed that when the speed of the machine was 2.8 km/h, the theoretical plant spacing was 20 cm, and the transplanting frequency reached 62 plants/(min·row), the qualified rate of seedlings was 96.3%, the leakage rate of seedlings was 2.8%, the seedling injury rate was 1.25%, the qualified rate of transplanting depth was 93.5%, the qualified rate of the plant spacing was 94.7%, the spacing variation coefficient was 7.9%, and the qualified rate of transplanting achieved 93.4%. Meanwhile, in the process of transplanting test, the drip irrigation pipe was laid and had not been damaged and bent at all again, and the performance of mulch film laying and soil covering was also excellent; by statistics and calculation, the flattening degree of plastic film lighting surface reached 98.2%, the qualified rate of plastic film lighting surface width achieved 97.8%, and the average mechanical damage degree of film surface was only 3.4 mm/m<sup>2</sup>. Therefore, the performance indices of 2ZXM-2 automatic plastic film mulch plug seedling transplanter can perfectly meet the agronomic requirements of pepper seedling transplanting. In conclusion, the research for this transplanter not only provides some theoretical basis and reference for the study of automatic dry land transplanter in China, and it also has important significance for the development of mechanized seedling transplanting technology in Xinjiang. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:31
Main heading:Seed
Controlled terms:Agricultural machinery - Agriculture - Automation - Crops - Cultivation - Fruits - Irrigation - Lighting - Pickups - Plastic films - Plastic pipe - Soils - Testing - Transplants - Vegetables
Uncontrolled terms:Drip irrigation pipes - Plastic film mulching - Plug seedling - Seedling transplanting - Seedlings transplanting - Semi-automatic machines - Temperature differences - Transplanting machine
Classification code:462.4 Prosthetics - 483.1 Soils and Soil Mechanics - 731 Automatic Control Principles and Applications - 817.1 Polymer Products - 821 Agricultural Equipment and Methods; Vegetation and Pest Control
Numerical data indexing:Percentage 1.25e+00%, Percentage 2.80e+00%, Percentage 7.90e+00%, Percentage 9.34e+01%, Percentage 9.35e+01%, Percentage 9.47e+01%, Percentage 9.63e+01%, Percentage 9.78e+01%, Percentage 9.82e+01%, Size 2.00e-01m, Velocity 7.78e-01m/s
DOI:10.11975/j.issn.1002-6819.2017.15.003
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 37>
Accession number:20174204272507
Title:Development of real-time and automatic measuring equipment for runoff and sediment
Authors:Zhan, Xiaoyun (1, 2); Guo, Minghang (1, 2); Zhao, Jun (1, 2); Zhao, Xianghui (3)
Author affiliation:(1) State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Northwest A&F University, Yangling; 712100, China; (2) Institute of Soil and Water Conservation, CAS&MWR, Yangling; 712100, China; (3) Xi'an San Intelligent Technology Co,LTD, Xi'an; 710075, China
Corresponding author:Zhao, Jun(zhaojun629@vip.sina.com)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:112-118
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Monitoring processes of runoff and sediment are the foundation of the dynamic assessment of soil erosion. Runoff volume and sediment concentration are 2 important hydrodynamic parameters to forecast slope runoff variation, reveal soil erosion mechanism and find out movement rule of soil in the field. However, the equipment which can be used widely to monitor precisely the runoff volume and sediment concentration at the same time is lacking. In view of the inaccuracy or the lack of equipment for automatic monitoring of runoff and sediment processes, real-time and automatic measuring equipment with high precision was explored in this study. The equipment could be applied to multi-scenario, including runoff plot and watershed. In our study, firstly, through the integration of signal sensing and automatic control technology, physical characteristics driving the operation of the equipment were extracted and converted into TT&C signals to automatically monitor runoff and sediment yield processes. On the one hand, continuous flow of runoff and sediment was discretized by optimizing the design of equipment overall structure and the functional unit. On the other hand, optical material of sampling device was used and the most reasonable shape and surface treatment of sampling device was designed, to reduce the influences of sediment adhesion and deposition on the accuracy and precision of measurement. Finally, based on "internet+" framework, a cloud station/data management platform was established, including station management, data integration, calculation and analysis, and application service. The equipment was able to get the values of runoff volume and sediment concentration synchronously, which overcame the limitation of tradition method. Furthermore, the reliability and applicability of the equipment were validated by the simulation experiment, and the results showed that the relative error of sediment concentration was averaged as 3.67%. Specifically, the relative error was averaged as 7.00%, when the sediment concentration was less than10 kg/m<sup>3</sup>, and when the sediment concentration varied from 20 to 90 kg/m<sup>3</sup>and from 100 to 300 kg/m<sup>3</sup>, the averaged relative errors were 3.10% and 2.61% respectively. The relative error greater than 10% accounted for only 3.70% of the total samples, while the relative error of the remaining 96.3% was less than 10%. The results also showed that the slope of linear regression between measured and actual sediment concentration was close to 1, and the coefficient of determination was up to 0.997. The research demonstrates that the equipment can detect precisely the dynamic processes of runoff volume and sediment concentration. We also monitored the dynamic process of runoff volume and sediment concentration through soil bin simulation experiment, and found that runoff volume varied from 19 to 127 L/s, with an average of 75.5 L/s, sediment concentration ranged from 4.6 to 275.1 kg/m<sup>3</sup>, and sediment concentration in the single rainfall was, on average, 88.6 kg/m<sup>3</sup>. The finding demonstrates that the equipment is capable of monitoring the large variation of runoff and sediment concentration, and can be used to complex field observations, and therefore, the self-designed equipment for auto-sampling water from runoff has a good prospect. This research can provide new techniques and methods for water and soil loss study, and promote the automation and informatization in water and soil loss monitoring. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:29
Main heading:Runoff
Controlled terms:Automation - Data integration - Dynamics - Equipment - Erosion - Errors - Information management - Sedimentation - Sediments - Soils - Surface treatment
Uncontrolled terms:Accuracy and precision - Automatic control technologies - Automatic monitoring - Coefficient of determination - Hydrodynamic parameters - Physical characteristics - Runoff and sediment yields - Sediment concentration
Classification code:442.1 Flood Control - 483 Soil Mechanics and Foundations - 483.1 Soils and Soil Mechanics - 723.2 Data Processing and Image Processing - 731 Automatic Control Principles and Applications - 802.3 Chemical Operations - 901 Engineering Profession
Numerical data indexing:Mass_Density 2.00e+01kg/m3 to 9.00e+01kg/m3, Mass_Density 4.60e+00kg/m3 to 2.75e+02kg/m3, Mass_Density 8.86e+01kg/m3, Percentage 1.00e+01%, Percentage 2.61e+00%, Percentage 3.10e+00%, Percentage 3.67e+00%, Percentage 3.70e+00%, Percentage 7.00e+00%, Percentage 9.63e+01%, Mass_Density 1.00e+02kg/m3 to 3.00e+02kg/m3
DOI:10.11975/j.issn.1002-6819.2017.15.014
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 38>
Accession number:20174204272524
Title:Thermal performance experiment for multiple clamber trough solar air collector with dual collector tubes for solar greenhouse
Authors:Chen, Chao (1); Zhang, Mingxing (1); Zheng, Hongfei (2); Li, Na (1); Ma, Xinglong (2); Ling, Haoshu (1); Ma, Caiwen (3); Zou, Ping (3)
Author affiliation:(1) College of Architecture and Civil Engineering, Beijing University of Technology, Beijing; 100124, China; (2) School of Mechanical Engineering, Beijing Institute of Technology, Beijing; 100081, China; (3) Institute of Agricultural Mechanization, Xinjiang Academy of Agricultural Science, Urumqi; 830091, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:245-252
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Because of its simple structure, pipeline without cracking in winter and other advantages, solar air collectors are getting more and more applications in industry, agriculture and residence. However, air has the disadvantages of small specific heat and density, so how to increase the collector efficiency and heat collection of air collectors has become the focus of research on solar air collectors. In recent years, multi-surface condenser air collector has gradually developed, which has the advantages of small size, easy installation and maintenance management, and high outlet temperature. Our research team has put forward a multi-chamber trough solar air collector with single collector tube. However, it has the shortcomings of low air flow and low heat collection efficiency however. In order to improve solar greenhouse solar energy utilization, this study proposed a new type of multi-chamber trough solar air collector with dual collector tubes to improve the collector performance. This collector is combined with the heat storage ventilation wall of solar greenhouse with solar active-passive "triple" structural phase change to constitute the active solar thermal storage system, which is used in Urumqi solar greenhouse. Based on the theory of optics and heat transfer, the experiment was designed and carried out to investigate the influence discipline of different parameters on thermal performances and optical performances for multi-chamber trough solar air collector with dual collector tubes. The parameters include the structure size (the relative position and the length of double collector tubes), air velocity inside the collector, inlet air temperature, and solar radiation. The test instruments include air collector, temperature sensor, flowmeter and data collection system. The experiment results illustrate that the collector performance of the double-tube collector is better than that of the single tube collector. Compared with the single collector tube concentrator, the air flow of the dual increased by 100%, the heat collection per unit area of the dual increased by 16%, and the heat collection efficiency of the dual increased by 9% (the heat collection efficiency of the dual was 44%-52% without tracking in winter). The relative position of double collector tubes, air velocity inside the collector and inlet air temperature were discussed in the study. The relative position 1 of double collector tubes is the best and the best air flow rate in the tube is 1.8-2.0 m/s. The collector was also applied to the solar greenhouse in Urumqi, and the results illustrate that: From November 2015 to February 2016, when the collector length is 16 m and the air velocity inside the concentrator is 2.0 m/s, the heat collecting system can provide solar thermal energy of about 50-65 MJ/day for solar greenhouse on the condition of sunny days, 35-45 MJ/day on the condition of cloudy days and 20-25 MJ/day on the condition of overcast days which have weak solar radiation. The heat collecting system can provide solar thermal energy of about 5 325 MJ for solar greenhouse by active heat storage of the wall in whole winter. This study can provide the reference for the thermal performance optimization of the collector and the new technical support for the efficient use of solar energy in solar greenhouse. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:29
Main heading:Collector efficiency
Controlled terms:Air - Applications - Atmospheric temperature - Concentration (process) - Digital storage - Energy utilization - Greenhouses - Heat storage - Heat transfer - Solar collectors - Solar energy - Solar heating - Solar radiation - Specific heat - Temperature - Thermal energy - Thermal load - Tubes (components)
Uncontrolled terms:Air collectors - Concentrating performance - Data collection system - Focus of researches - Heat collection - Inlet air temperatures - Maintenance management - Solar thermal energy
Classification code:443.1 Atmospheric Properties - 451.2 Air Pollution Control - 525.3 Energy Utilization - 619.1 Pipe, Piping and Pipelines - 641.1 Thermodynamics - 641.2 Heat Transfer - 657.1 Solar Energy and Phenomena - 702.3 Solar Cells - 722.1 Data Storage, Equipment and Techniques - 804 Chemical Products Generally - 821.6 Farm Buildings and Other Structures
Numerical data indexing:Energy 5.32e+09J, Percentage 1.00e+02%, Percentage 1.60e+01%, Percentage 4.40e+01% to 5.20e+01%, Percentage 9.00e+00%, Size 1.60e+01m, Velocity 1.80e+00m/s to 2.00e+00m/s, Velocity 2.00e+00m/s
DOI:10.11975/j.issn.1002-6819.2017.15.031
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
<RECORD 39>
Accession number:20174204272518
Title:Analysis of spatio-temporal distribution of drought characteristics based on SPEI in Inner Mongolia during 1960-2015
Authors:Zhang, Xuting (1); Pan, Xuebiao (1); Xu, Lin (1); Wei, Pei (1); Yin, Ziwei (1); Shao, Changxiu (1)
Author affiliation:(1) College of Resources and Environmental Sciences, China Agricultural University, Beijing; 100193, China
Corresponding author:Pan, Xuebiao(panxb@cau.edu.cn)
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:33
Issue:15
Issue date:August 1, 2017
Publication year:2017
Pages:190-199
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Grassland animal husbandry and rainfed farming are two pillar industries in Inner Mongolia agriculture, and they are vulnerable to natural disasters, especially drought. Analysis of spatio-temporal distribution of drought characteristics in Inner Mongolia is important for local government to tackle climate change. In order to define the spatiotemporal distribution of drought characteristics and its response to climate change in Inner Mongolia at different time scales, monthly data from 46 meteorological stations for the period 1960-2015 were selected in this study, including monthly sunshine hours, wind speed at 10m height, mean temperature, maximum temperature, minimum temperature, precipitation, relative humidity, station pressure and so on. The standardized precipitation evapotranspiration index (SPEI) was established using precipitation and potential evapotranspiration (ET<inf>0</inf>) data at different time scales, in which ET<inf>0</inf>was calculated by FAO Penman-Monteith equation instead of Thornthwaite formula. In order to find out the drought characteristics, Mann-Kendall test, drought indices, climate tendency rate, empirical orthogonal function (EOF) analysis and rotated empirical orthogonal function (REOF) analysis were carried out on the precipitation, ET<inf>0</inf>and SPEI. Considering of the pacific decadal oscillation (PDO), the correlation of SPEI with PDO index in Inner Mongolia was also discussed. The results of this research showed that from the inter-annual changes, it showed a humid trend with an abrupt change in 1976 in Inner Mongolia. On the other hand, from the seasonal perspective, it was getting wet in spring (P<0.05) and winter, and there was a drought trend in summer and autumn. The drought coverage appeared as the features of the local and domain drought at the annual scale, and the intensity of drought were light and moderate mainly. Spatially, the western regions had a humid trend, but it was drier in the eastern part of Inner Mongolia on the contrary. Most regions were getting dry in summer (P<0.05) and autumn, and wet in spring and winter. According to the strength of arid sensitivity in Inner Mongolia, it can be divided into 4 sub-regions: Western region (I sub-region), central region (II sub-region), north district in the northeastern region (III sub-region) and south district in the northeastern region (IV sub-region). Drought in I and II sub-regions was gradually alleviated, III and IV sub-regions showed a trend of getting dry. A 12-month-scale SPEI exhibited positive correlation with PDO index since 1960. When it was negative in PDO index, there was quite dry period in Inner Mongolia, otherwise a humid trend. According to the correlation of PDO index with SPEI, it could further prove that there was a significant positive correlation (P<0.05) between PDO index and SPEI, in other words, pacific decadal oscillation had great positive influence on climate and drought characteristics in Inner Mongolia. The record events of the typical drought duration, scale and intensity in yearbook were basically the same with characteristics of calculated SPEI in this paper, which showed SPEI and drought events had good agreement. SPEI could well reflect typical historical drought events, and it had an indicative effect on drought to some extent in Inner Mongolia. The results of this research could be used in assessing the hydrothermal condition scientifically in Inner Mongolia, and could also provide theoretical basis for forecasting and preventing drought disaster. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
Number of references:30
Main heading:Climate change
Controlled terms:Agriculture - Difference equations - Disaster prevention - Disasters - Drought - Evapotranspiration - Orthogonal functions - Precipitation (chemical) - Wind
Uncontrolled terms:Eastern part of inner mongolia - Empirical Orthogonal Function - Empirical orthogonal function analysis - Pacific decadal oscillation - Penman-Monteith equations - Potential evapotranspiration - Spatiotemporal distributions - SPEI
Classification code:443.1 Atmospheric Properties - 444 Water Resources - 802.3 Chemical Operations - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 914.1 Accidents and Accident Prevention - 921 Mathematics - 921.6 Numerical Methods
Numerical data indexing:Size 1.00e+01m
DOI:10.11975/j.issn.1002-6819.2017.15.025
Database:Compendex
Compilation and indexing terms, Copyright 2017 Elsevier Inc.
期刊信息
- 主管单位 中国科学技术协会
- 主办单位 中国农业工程学会
- 主编 朱明
- 总编/社长 王应宽
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