<RECORD 1>
Accession number:20152701006252
Title:Soil organic polluted matter phenol migration characteristics in modified loessial soil
Authors:Di, Xin (1); Meng, Zhaofu (2); Yang, Shuying (1); Cui, Xiaobo (1); Xiang, Wei (2); Ren, Wenli (2); Yang, Yali (1); Li, Wenbin (2); Wu, Qiong (2)
Author affiliation:(1) College of Science, Northwest A&F University, Yangling, China; (2) College of Resource and Environment, Northwest A&F University, Yangling, China; (3) Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, China
Corresponding author:Meng, Zhaofu
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:249-255
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In order to prevent and control longitudinal migration of pollutants in soil and protect the groundwater from pollution, saturated soil column transport experiments were conducted, and the software CXTFIT2.1 was used for fitting the parameters from the experiments. This study aimed to explore retarding effect of the cetyltrimethylammonium bromide (CTMAB) modified soil and raw soil on migration of phenol, and to investigate the effect of modification ratio, pH, ionic strength on phenol migration in soil column. The results showed that with the software CXTFIT2.1, the deterministic equilibrium CDE (EM) model can be used to simulate breakthrough curves of Cl<sup>-</sup>, and the deterministic non-equilibrium CDE (NEM) model can be used to simulate breakthrough curves of phenol well. Non-reactive Cl<sup>-</sup> was used to determine the soil column parameter dispersion coefficient when average pore water velocity v was fixed. Then the average velocity of pore water and dispersion coefficient were used to calculate the transport parameter retardation factor of the reactive solute phenol. Clay layer of Lou soil modified by CTMAB significantly enhanced the retardant ability of soil for phenol migration. The greater the modification ratio was, the later the flow time of phenol was, and the greater the retardation coefficient was. With the modification ratio increasing from 0 to 100%, the flow time of phenol was delayed by 3.90 to 82.65 pv, and the retardation coefficient increased from 0.48 to 12.51. So the increase of modified soil proportion can block phenol transportation, and increase the retention quantity of phenol. In other words, the retention ratio more than 25% modification ratio soil samples reached about 50% for phenol, while the retention ratios of CK and 10% modification ratio soil samples for phenol were only about 20%. The pH values ranging from 6.0 to 8.0 had almost no effects on blocking phenol migration in the modified soils. The flow time of phenol in raw soil remained at around 0.45 pv, and the retardation coefficient was about 2.00. The flow time of phenol in 100% modified soil remained at around 12.30 pv, and the retardation coefficient was about 60.50. The larger ionic strength was, the earlier the flow time of phenol was, and the smaller the retardation coefficient was. With the ionic strength increasing from 0.001 to 0.1 mol/L, the flow time of phenol in raw soil was advanced from 4.07 to 3.42 pv, and the retardation coefficient dropped from 0.56 to 0.37. The flow time of phenol in 100% modified soil was advanced from 130.47 to 55.27 pv, and the retardation coefficient dropped from 17.57 to 8.71. So the rise of ionic strength can decrease retardant ability of raw soil and 100% modified soil. Therefore, increasing ionic strength can promote the migration of phenol, and decrease retardant ability in raw soil and modified soil. The retarding effect of the 100% modified soil for phenol migration in neutral environment was best when ionic strength was 0.001 mol/L. This study has an important significance for the repair or control of the organic modified soil on soil and groundwater pollution. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:28
Main heading:Soil pollution
Controlled terms:Groundwater - Groundwater pollution - Ionic strength - Organic compounds - pH - pH effects - Phenols - Pollution - Pollution control - Soil pollution control - Soil surveys - Soils - Water
Uncontrolled terms:Cetyl trimethyl ammonium bromides - Cetyltrimethylammonium bromide - Dispersion coefficient - Migration - Parameter dispersion - Retardation factors - Transport experiments - Transport parameters
Classification code:444 Water Resources - 444.2 Groundwater - 454.2 Environmental Impact and Protection - 483.1 Soils and Soil Mechanics - 801.1 Chemistry, General - 801.4 Physical Chemistry - 804.1 Organic Compounds
DOI:10.11975/j.issn.1002-6819.2015.11.036
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 2>
Accession number:20152701006259
Title:Ripeness classification of Shajin apricot using hyperspectral imaging technique
Authors:Xue, Jianxin (1); Zhang, Shujuan (1); Zhang, Jingjing (1)
Author affiliation:(1) College of Engineering, Shanxi Agricultural University, Taigu, China
Corresponding author:Zhang, Shujuan
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:300-307
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Nondestructive detection of fruit ripeness is crucial for improving fruit's shelf life and industry production. Hyperspectral imaging is an emerging technique that integrates conventional imaging and spectroscopy to acquire both spatial and spectral information from a sample. It takes the advantages of the conventional RGB, near-infrared spectroscopy and multi-spectral imaging. In this work, hyperspectral imaging technology intended to determine a classifier that could be used for nondestructive classification for the ripeness of Shajin apricot. There were 480 Shajin apricot samples to be investigated, which were from an apricot planting garden in Xiaobai Village, Taigu County, and the samples were classified into 4 classes: unripe, mid-ripe, ripe and over-ripe according to the days after harvesting. Hyperspectral imaging technology with the band range of 400-1000 nm was used to evaluate nondestructively the ripeness of the Shajin apricot. The 480 RGB images were acquired for the apricot samples with 4 different ripeness classes (120 for each class). After acquiring hyperspectral images of Shajin apricot, the spectral data were extracted from the region of interests (ROIs). Using Kennard-Stone algorithm, all kinds of samples were randomly divided into training set (360) and test set (120) according to the proportion of 3:1. In this work, the soluble solid content (SSC) was chosen as an evaluation index of maturity for Shajin apricot. First of all, one-way analysis of variance (ANOVA) was used to evaluate the SSC of 480 samples of intact Shajin apricots at different ripeness stages. The results indicated that SSC presented significant differences among the different ripeness classes and had a increasing tendency along with the development of ripeness, which demonstrated that there was a high correlation between maturity and SSC with the correlation coefficient of 0.9386. Subsequently, based on the calculation of partial least squares regression (PLSR), 9 wavelengths at 434, 528, 559, 595, 652, 678, 692, 728 and 954 nm were selected as the optimal sensitive wavelengths (SWs), 6 statistical textural parameters of hyperspectral images including mean, contrast, correlation, energy, homogeneity and entropy were extracted by gray level co-occurrence matrix (GLCM) as the textural feature variables, and 6 statistical color indicators of hyperspectral images including mean values and standard deviations of R, G and B component image were extracted by RGB model as the color feature variables for the purposes of ripeness classification. Moreover, the ability of hyperspectral imaging technique to classify Shajin apricot based on ripeness stage was tested using the extreme learning machine (ELM) models. The ELM ripeness classification models were built based on the extracted SWs, texture, color, combination of SWs and texture, combination of SWs and color, combination of texture and color, combination of SWs, texture and color features, respectively. The results showed the correct discrimination rate was the highest for the prediction samples based on SWs and color features, and it reached 93.33%. The research reveals that the hyperspectral imaging technique together with suitable analysis model is a promising tool for rapid estimation of quality attribute and ripeness classification for Shajin apricot, which can provide a theoretical reference and basis for designing classification system of fruits in further work. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:27
Main heading:Analysis of variance (ANOVA)
Controlled terms:Algorithms - Color - Fruits - Image acquisition - Image processing - Imaging techniques - Infrared devices - Knowledge acquisition - Learning systems - Least squares approximations - Models - Near infrared spectroscopy - Nondestructive examination - Quality control - Spectroscopy - Textures
Uncontrolled terms:Extreme learning machine - Hyperspectral Imaging - Imaging processing - Ripeness - Shajin apricot
Classification code:421 Strength of Building Materials; Mechanical Properties - 723 Computer Software, Data Handling and Applications - 723.4 Artificial Intelligence - 741 Light, Optics and Optical Devices - 746 Imaging Techniques - 801 Chemistry - 821.4 Agricultural Products - 902.1 Engineering Graphics - 913.3 Quality Assurance and Control - 921.6 Numerical Methods - 922 Statistical Methods - 933 Solid State Physics
DOI:10.11975/j.issn.1002-6819.2015.11.043
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 3>
Accession number:20152701006248
Title:Control method for greenhouse climate based on temperature integration
Authors:Yuan, Hongbo (1); Li, Li (1); Wang, Junheng (1); Sigrimis, N.A. (3)
Author affiliation:(1) Key Laboratory on Modern Precision Agriculture System Integration Research of Ministry of Education, China Agricultural University, Beijing, China; (2) College of Mechanical and Electrical Engineering, Agricultural University of Hebei, Baoding, China; (3) Department of Agricultural Engineering, Agricultural University of Athens, Athens, Greece
Corresponding author:Li, Li
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:221-227
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In recent years, horticulture industry has been rapidly developed in China. The total area of cultivation is about 3.79 million hm<sup>2</sup> by the end of 2012, but the climate control methods in actual greenhouse production are still relatively simple. Although many of the advanced intelligent control algorithms have been studied, however, there are two problems of these intelligent algorithms: the first one is the intelligent algorithms depend on the model of the greenhouse at the time of the operation. The control effect is better, only if the greenhouse model is accurate, but the greenhouse is a multivariable complex system with high coupling, so it is difficult to obtain accurate models. In addition, there are many different types of greenhouse in China, and each greenhouse structure may not be exactly the same, so it is inconsistent with the theoretical model. The second problem of intelligent algorithms is a large number of calculations are performed; the requirement is high for greenhouse controller's processing capability and computing capability. The typical method for the climate control is to configure the static set point in actual greenhouse production, and the energy will be wasted because the static set point can not be automatically adjusted according to the external environment. In order to solve this problem, the greenhouse climate control method based on temperature integration was studied. When using this method, the first thing was to determine the expected average temperature, the maximum temperature and the minimum temperature in a certain period of time according to the type and growth stage of crop. Secondly, the actual average temperature of the current date would be calculated by the expected average temperature and the actual average temperature of previous day. Thirdly, the days were divided into N equal time intervals, and the length of each interval was int. The temperature set point of current time interval n would be calculated according to the actual average temperature and actual average temperature of previous n days, and the temperature set point contained 2 values: heating set point and cooling set point. Then the actual temperature of the time interval n and the temperature set point were compared. It would be heated if the actual temperature was lower than the heating set point, and the cooling would be operated if the actual temperature was higher than the cooling set point, otherwise no operation would be performed. Two comparative experiments were designed to verify this method using greenhouse simulation software, one experiment used the static set point to control the greenhouse temperature and the other experiment controlled it by temperature integration algorithm. In the greenhouse simulation program, a heater was for heating with the efficiency of 400 W/m<sup>2</sup>, a ventilation window for cooling, and the samples were collected once every 10 min which collected information such as time, internal temperature, humidity, heater working state and ventilation working state and a total of ten-day system simulation. The static set point temperature range was 16-25, the actual average temperature in greenhouse was 18.62 at the end of the simulation, and all of heating energy consumption was 167.39 GJ. The same temperature 18.62 was set as the expected temperature by the temperature integration algorithm for the control of greenhouse temperature. For the sake of obtaining the most solar radiation energy and reduce the heating energy, the maximum temperature was set to 30, the minimum temperature was 10 and the integral time was 2 days. The actual average temperature in the greenhouse was 20.21 and the total energy consumption for heating was 164.08 GJ by the temperature integration algorithm, and 98% of energy was used but the temperature of greenhouse was improved by 1.09 times through this method. The advantage of this method was proved by the more experiments in which the expected average temperatures were set to 17, 16 and 15, the actual average temperature in the greenhouse were corresponding to 19.67, 19.14 and 18.61 and the consumption of heater were 143.46, 126.07 and 107.85 GJ respectively. It can be seen by the results that the temperature integration algorithm has used only 64.43% of the energy but is able to achieve the same effect compared with the static set point method. Furthermore, the algorithm is simple and less calculation compared with the intelligent algorithms. Therefore, it can be used in common greenhouse controller and it has obvious energy-saving effect, but the greenhouse owners do not have to increase investment. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:29
Main heading:Greenhouse effect
Controlled terms:Algorithms - Climate control - Computer software - Controllers - Energy conservation - Energy utilization - Environmental testing - Greenhouses - Heating - Integration - Integration testing - Investments - Problem solving - Structural analysis - Temperature
Uncontrolled terms:Comparative experiments - Greenhouse climate control - Heating energy consumption - Integration algorithm - Intelligent Algorithms - Set-point temperatures - Temperature integration - Total energy consumption
Classification code:402 Buildings and Towers - 402.1 Industrial and Agricultural Buildings - 408.1 Structural Design, General - 451 Air Pollution - 454 Environmental Engineering - 525.2 Energy Conservation - 525.3 Energy Utilization - 641.1 Thermodynamics - 643.1 Space Heating - 723 Computer Software, Data Handling and Applications - 723.5 Computer Applications - 732.1 Control Equipment - 911.2 Industrial Economics - 921 Mathematics - 921.2 Calculus
DOI:10.11975/j.issn.1002-6819.2015.11.032
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 4>
Accession number:20152701006240
Title:Effect of low atmospheric pressure of plateau environment on air content and bubble stability of air-entrained concrete
Authors:Li, Xuefeng (1); Fu, Zhi (1)
Author affiliation:(1) Research Institute of Highway Ministry of Transportation, Beijing, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:165-172
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The effect of atmospheric pressure reduction of environment on air content and bubble stability of air-entrained concrete were experimentally studied using low-pressure test chamber to stimulate the plateau environment. Three different mixing proportions and three different levels of the initial air content of concretes were prepared for study, and four different common types of air-entraining admixture, saponin, alkyl sulfonate, abietic soap and polyether, were used in the experiments. The results indicated that the change of atmospheric pressure of environment had a significant impact on the performance of air-entraining admixtures. When the mix proportions of concrete and the amount of air-entraining admixtures took a certain value respectively, the air content of fresh concrete decreased linearly with the drop of atmospheric pressure. When the atmospheric pressure was 50 kPa, the air content of fresh concrete fell by roughly 20% to 49%. The higher the air content of fresh concrete mixed in normal atmospheric pressure, the faster the air content of fresh concrete decreased with the drop of atmospheric pressure. Among the four common types of air-entraining admixture used in the experiment, the air-entraining ability of saponin was the least influenced by the drop of atmospheric pressure and the abietic soap was the most. In addition, the bubble stability of fresh concrete mixed under low atmospheric pressure was poor than the one under the normal atmospheric pressure. The air content of the fresh concrete mixed under the low atmospheric pressure decreased more rapidly within 50-55 minutes after finish of the mixing and the spacing factor increased obviously as time went on. Besides, whatever the concrete was mixed under the low or the normal atmospheric pressure, the air content of fresh concrete decreased and the spacing factor of hardened concrete increased with vibration time extended from 0 second to 90 seconds, but it was more obvious within 30 seconds. Therefore, in order to meet the design requirements of air content of air-entrained concrete for different constructions in the plateau regions, the following measures were recommended: 1) the air-entraining admixture with good air entraining ability and foam stabilization performance should be chosen for the plateau environment, 2) according to different pressure conditions and types of air-entraining admixture, the dosages of air entraining admixture should be increased so that air content of concrete could fully meet the design requirements, and 3) during the construction in the plateau regions, the vibration time should be reduced with the precondition of the impaction of concrete if possible to avoid air content loss. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:23
Main heading:Pressure effects
Controlled terms:Air - Atmospheric pressure - Concrete additives - Concrete mixing - Concrete reinforcements - Concretes - Drops - Metabolites - Mixing - Stability
Uncontrolled terms:Air content of concrete - Air entraining admixtures - Air-entrained concrete - Bubble stability - Different pressures - Low atmospheric pressures - Normal atmospheric pressure - Spacing factor
Classification code:412 Concrete - 412.2 Concrete Reinforcements - 443.1 Atmospheric Properties - 801 Chemistry - 801.2 Biochemistry - 802.3 Chemical Operations - 804 Chemical Products Generally - 931 Classical Physics; Quantum Theory; Relativity - 931.1 Mechanics - 951 Materials Science - 961 Systems Science
DOI:10.11975/j.issn.1002-6819.2015.11.024
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 5>
Accession number:20152701006234
Title:Response of precipitation to ratio of canal to wells and its environmental effects analysis in combined well-canal irrigation area
Authors:Li, Ping (1); Qi, Xuebin (1); Magzum, Nurolla (4); Huang, Zhongdong (1); Liang, Zhijie (3); Qiao, Dongmei (4)
Author affiliation:(1) Farmland Irrigation Research Institute of CAAS, Xinxiang, China; (2) Institute of Water Resources and Hydro-electric Engineering, Xi'an University of Technology, Xi'an, China; (3) Agriculture Water and Soil Environmental Field Science Research Station of Xinxiang City Henan Province of CAAS, Xinxiang, China; (4) Key Laboratory of High-efficient and Safe Utilization of Agriculture Water Resources of CAAS, Xinxiang, China
Corresponding author:Qi, Xuebin
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:123-128
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The suitable ratio of canal to well in the combined well-canal irrigation area can contribute to safety of groundwater environment and sustainable regional agriculture production. In order to investigate the influence of canal-to-well ratio on regional soil salinity accumulation, dynamics of groundwater depth, and groundwater hydrochemical characteristics in combined well-canal irrigation area, this study was carried out in a typical area in the People's Victory Canal area in China. The agriculture water consumption and precipitation in the People's Victory Canal area from 1954 to 2014 were collected, and the canal-to-well ratio, dynamics of groundwater depth and hydrochemical characteristics of groundwater from 2008 to 2014 in the research area were analyzed. The relationships between precipitation, groundwater depth, groundwater hydrochemical characteristics and the canal-to-well ratio were explored. The results indicated that there was a significant positive correlation between canal-to-well ratio and annual precipitation in research area (P<0.05). The variation coefficient of groundwater depth in the upstream of branch canals was higher than that of downstream of branch canals. Accumulated variation in soil electrical conductivity at 0-100 cm depth of 2nd branch canal was less than that of 1st branch canal and 3rd branch canal by 4.77% and 5.55%, respectively. Compared with the year of 2013, the area of groundwater depth greater than 11 m in 1st branch canal, 2nd branch canal and 3rd branch canal during the wintering period of winter wheat in 2014 was increased by 31.78%, 25.07% and 40.81%, respectively. When the water consumption amount and method were same, the high canal-to-well ratio can result in a small increase of area with groundwater depth beyond 11 m, indicating that the high canal-to-well ratio can alleviate the deterioration of groundwater depth. Alkaline trend of groundwater during dry and normal seasons in the research area was obvious owing to unrestrained groundwater exploitation. Affected by climate change, the reduction of precipitation in the combined well-canal irrigation area was obvious. Meanwhile, average irrigation amount by canal in the past 5 years was 2.90×108 cm<sup>3</sup>, accounting for 75.52% of mean annual irrigation amount. On the other hand, ground water overdraft in the research area would be remained in order to ensure agricultural sustainable production, which would be bound to aggravate alkaline trend of groundwater and expand the range of deep groundwater zone. It could be concluded that the suitable ratio of canal to wells decreased the groundwater exploitation and alleviated the alkaline trend of groundwater environment, moreover, maintained the reasonable groundwater depth. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:16
Main heading:Canals
Controlled terms:Agriculture - Climate change - Groundwater - Groundwater resources - Hydraulic structures - Hydrochemistry - Irrigation - Precipitation (chemical) - Rivers - Soils - Sustainable development
Uncontrolled terms:Agriculture productions - Canal irrigation - Groundwater environment - Groundwater exploitation - Hydrochemical characteristics - Soil electrical conductivity - Sustainable production - Variation coefficient
Classification code:407.2 Waterways - 441 Dams and Reservoirs; Hydro Development - 444.1 Surface Water - 444.2 Groundwater - 451 Air Pollution - 481.2 Geochemistry - 483.1 Soils and Soil Mechanics - 611 Hydroelectric and Tidal Power Plants - 802.3 Chemical Operations - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 821.3 Agricultural Methods - 911.2 Industrial Economics
DOI:10.11975/j.issn.1002-6819.2015.11.018
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 6>
Accession number:20152701006243
Title:Remote sensing identification method for paddy field in hilly region based on object-oriented analysis
Authors:Yi, Fengjia (1); Li, Rendong (1); Chang, Bianrong (1); Qiu, Juan (1)
Author affiliation:(1) Institute of Geodesy and Geophysics., Chinese Academy of Sciences, Wuhan, China; (2) Key Laboratory for Environment and Disaster Monitoring and Evaluation of Hubei Province, Wuhan, China; (3) Faculty of Earth Sciences, University of Chinese Academy of Sciences, Beijing, China
Corresponding author:Li, Rendong
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:186-193
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Identification of paddy fields in the hilly regions is important for policy making of food self-sufficiency in China. However, extracting image information using current image analysis techniques is difficult because of the unique terrain of hilly regions. The traditional pixel-based analysis of remotely sensed data is usually affected by pixel heterogeneity, mixed pixels, and spectral similarity, thus leading to the inaccurate identification of paddy fields in hilly regions. This study aimed to find other methods for accurate paddy field identification in hilly regions. The study area was Xiangtan City located in the mid-east of Hunan province, a good representative of hilly regions. In Xiangtan city, the land use change markedly increases with rapid economic development, leading to gradual decline of cultivated land. The Chinese environment and disaster mitigation satellite (i.e., HJ-1A/1B) image of the region was data source for land use map. The HJ-1A star was equipped with a charge-coupled device (CCD) camera and a hyperspectral imager, whereas the HJ-1B star was equipped with CCD and infrared (IR) cameras. The satellite observes the ground in widths of 700 km with a ground pixel resolution of 30 m by four multispectral imaging steps. The object-oriented image analysis technique is a new type of automatic technique under a computer environment. The information carrier used was multi-scale objects composed of multiple adjacent pixels containing rich semantic information. Image segmentation is an important classification step because high-precision remote sensing (RS) image classification depends on good segmentation. The multi-scale image segmentation algorithm was applied in the preliminary object extraction to fully interpret the RS images with the different spectral features, shape, and textural features of real ground targets. The configuration of multi-scale segmentation thresholds directly affected the integrity of features extracted from RS images. In this study, the cultivated and uncultivated lands were segmented with the scale of 40; then the cultivated land was further segmented under the scale of 30 and 20, respectively. By comparing and analyzing the segmentation results on the two scales, the optimal scales for the extraction of paddy fields in different regions were configured selectively. The phenomenon of different objects with the same spectral characteristics and same object showing different spectral characteristics may occur in the classification of RS images. The two phenomena pose challenges for RS image interpretation. In order to identify the information related with paddy field distribution in hilly regions, the key point is the RS identification between paddy field, dry field, forest and grassland. According to the classification features, k-nearest neighbor (KNN) classifier and decision tree classifier were employed to interpret the RS images of paddy field in hilly regions. The KNN classifier was improved by dividing the training samples into three sets. The result of the improved KNN classifier was better than that of traditional methods. The precision of the improved KNN classifier was 74.6%. However, the total precision and Kappa coefficient of the decision tree classifier were higher than the KNN classifier. The total identification precision of the former reached 90.25%, with commission error rate of 4.12%, omission error rate of 5.63%, and Kappa coefficient of 0.79. A comparison of the results of the two classifiers showed that the decision tree classifier is more suitable for paddy field identification based on object-oriented analysis in hilly regions. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:26
Main heading:Image classification
Controlled terms:Cameras - Charge coupled devices - Decision trees - Economics - Extraction - Feature extraction - Image analysis - Image processing - Image segmentation - Land use - Motion compensation - Nearest neighbor search - Pixels - Remote sensing - Semantics - Spectroscopy - Stars
Uncontrolled terms:Cultivated lands - Decision tree classifiers - Hilly region - Image recognization - K-nearest neighbors - Object oriented - Paddy fields
Classification code:403 Urban and Regional Planning and Development - 657.2 Extraterrestrial Physics and Stellar Phenomena - 714.2 Semiconductor Devices and Integrated Circuits - 716 Telecommunication; Radar, Radio and Television - 731.1 Control Systems - 741 Light, Optics and Optical Devices - 741.1 Light/Optics - 742.2 Photographic Equipment - 801 Chemistry - 802.3 Chemical Operations - 903.2 Information Dissemination - 922 Statistical Methods - 961 Systems Science - 971 Social Sciences
DOI:10.11975/j.issn.1002-6819.2015.11.027
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 7>
Accession number:20152701006257
Title:Drying characteristics and product quality of Lycium barbarum under stages-varying temperatures drying process
Authors:Wu, Zhonghua (1); Li, Wenli (1); Zhao, Lijuan (1); Shi, Jianfang (2); Liu, Qing (2)
Author affiliation:(1) College of Mechanical Engineering, Tianjin University of Science and Technology, Tianjin, China; (2) Department of Agricultural Processing, Chinese Academy of Agricultural Engineering, Beijing, China
Corresponding author:Shi, Jianfang
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:287-293
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Lycium barbarum is a kind of fleshy berry in bright red, which is one of the well-known traditional Chinese medicines with rich nutrients. Currently, Lycium barbarum is widely dehydrated using sun-drying. This method is simple and low-cost, which are its advantages. But the drying time is long and its application is limited by the climate and sanitary conditions. Also, the dried product quality is difficult to control. In this paper, the multi-stage varying temperature hot air drying was conducted on Lycium barbarum to shorten the drying time and improve the dried product quality. This drying method was successfully applied in the drying processing of rice, cherry tomatoes, honeysuckle, etc. First, the hot air drying characteristics of Lycium barbarum were investigated under constant air temperature (40, 50 and 60), relative humidity (40%, 50% and 60%) and material thickness (8, 24, and 40 mm); and the product quality was evaluated through polysaccharide content, color and rehydration ratio of dried Lycium barbarum. The hot air drying experiments were conducted in a lab-scale SY-5 type fruit and vegetable drying room in which the hot air temperature and humidity could be pre-scheduled by programming. The polysaccharide of dried Lycium barbarum was extracted through the ultrasonic-aided water extraction method and then, its percent content was measured using the phenol-sulfuric acid method. The color of dried product was evaluated using the image technology and its red, yellow and blue color value could be obtained. The rehydration ratio was judged through soaking the dried Lycium barbarum in hot water (80) for 20 min and then measuring the mass of water absorbed. Experimental results under the constant drying temperature and humidity conditions showed that the drying time of Lycium barbarum decreased largely from above 48 to 15 h with the increase of air temperature from 40 to 60, also decreased slightly with the increase of relative humidity. The improvement of air temperature had a negative effect on the product qualities such as color, but the relative humidity had a small positive effect on product quality. When air temperature increased from 40 to 60, the contents of Lycium barbarum polysaccharides decreased from 7.76% to 7.20%. The red color value reduced from 13.9 to 12.9, the rehydration ratio varied from 50.0% to 51.4%. Thus, the drying temperature is the governing parameter in the hot air drying of Lycium barbarum. Then, several multi-stage varying temperature drying processings of Lycium barbarum were conducted and their dried product qualities were compared. The optimum drying condition obtained for the multi-stage varying temperature drying technology was the drying temperature of 40 (6 h)-50 (6 h)-60, relative humidity of 40% and three-layer material thickness. Under the optimum drying condition, the dried Lycium barbarum had a red color value of 13.7, polysaccharide content of 9.77% and rehydration ratio of 51.6%. Finally, The drying time and the product quality of Lycium barbarum with/without pre-treatment using 3% alkali solution were also compared and it was found that pre-treatment with 3% alkali solution for 1 min could shorten the drying time from 28 to 25 h, improve the red color value from 13.7 to 15.4 and rehydration ratio from 51.6% to 55.4%, and meanwhile polysaccharide content slightly decreased from 9.77% to 9.23%. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:18
Main heading:Drying
Controlled terms:Atmospheric humidity - Atmospheric temperature - Chemicals removal (water treatment) - Color - Extraction - Fruits - Humidity control - Medicine - Processing - Quality control - Solar dryers - Temperature - Thermal processing (foods)
Uncontrolled terms:Drying characteristics - Fruit and vegetables - Governing parameters - Hot air drying - Lycium barbarum - Polysaccharide contents - Traditional Chinese Medicine - Water extraction methods
Classification code:402 Buildings and Towers - 443.1 Atmospheric Properties - 461.6 Medicine and Pharmacology - 641.1 Thermodynamics - 741.1 Light/Optics - 802.1 Chemical Plants and Equipment - 802.3 Chemical Operations - 803 Chemical Agents and Basic Industrial Chemicals - 804 Chemical Products Generally - 821.4 Agricultural Products - 822.2 Food Processing Operations - 913.3 Quality Assurance and Control - 913.4 Manufacturing
DOI:10.11975/j.issn.1002-6819.2015.11.041
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 8>
Accession number:20152701006249
Title:Effect of different lighting quality and intensities on quality of rice seedling by greenhouse stereoscopic nursing
Authors:Ma, Xu (1); Lin, Chaohui (2); Qi, Long (1); Jiang, Likai (2); Tan, Yongxin (2); Liang, Zhongwei (2); Lu, Fangyuan (2)
Author affiliation:(1) Key Laboratory of Key Technology on Agricultural Machine and Equipment, Ministry of Education, South China Agricultural University, Guangzhou, China; (2) College of Engineering, South China Agricultural University, Guangzhou, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:228-235
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The technique of greenhouse stereoscopic seedling nursing in rice seedlings has many benefits, such as achieving the efficient use of seedling land and promoting standard centralized rice seedling. However, since multiple layers of seedbeds are stacked together and block light from each other, the problem of insufficient lighting arises from greenhouse stereoscopic nursing. Therefore, artificial supplemental lighting technology needs to be applied in the greenhouse in order to improve the illumination conditions of the seedbed layers, thus to enhance the quality of rice seedlings. In this paper, the range of flux ratio of red to blue light required for rice seedlings growth optimally was determined based on fundamental findings of the plant optical theoretical analysis; the light intensity distribution inside the greenhouse was calculated based on the theory of illumination analysis; and the light environment among the layers of seedbeds inside the greenhouse was simulated using the Ecotect software. Simulation results showed that, without artificial supplemental lighting, except the top layer, the light intensity on each seedbed layer couldn't meet the requirements of the rice seedlings growth. Based on the theoretical analysis and simulation results, the effects of different artificial lighting conditions on the growth quality of rice seedling were studied. In the study, LED plant lights were adopted to provide supplemental lighting to all seedbed layers except the top layer, and orthogonal experimental design was implemented to study the effects of the flux ratio of red to blue light, the light intensity and the frame spacing among the seedbed layers on rice seedlings quality. Experimental results from this study showed that the lighting condition with a flux ratio of red to blue light of 10:1 and a light intensity of 2500 lx was beneficial to promoting rice stem elongation and growth; the lighting condition with a flux ratio of red to blue light of 8: 1 was beneficial to retaining dry matters in rice seedlings and ensuring the tangle of the roots; and the rice seedlings processed by the lighting with a flux ratio of red to blue light of 8:1 had a higher healthy index compared to the rice seedlings processed by the lighting with a flux ratio of red to blue light of 6:1 or 10:1. The analysis of this study showed that the order of significance of the aforementioned 3 factors' effects on the quality of rice seedlings was: flux ratio of red to blue light>light intensity>frame spacing. The best artificial lighting condition was shown to be with a flux ratio of red to blue light of 8:1, a light intensity of 2500 lx and a frame spacing of 45 cm. The conclusions of this study may serve as a technical reference for industrialized stereoscopic rice seedlings applications and provide guidance to the greenhouse stereoscopic rice seedling nursing. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:29
Main heading:Light emitting diodes
Controlled terms:Greenhouse effect - Greenhouses - Light - Lighting - Nursing - Quality control - Stereo image processing
Uncontrolled terms:Analysis and simulation - Artificial lighting - Blue light - Frame spacing - Illumination conditions - Light intensity - Light intensity distribution - Orthogonal experimental design
Classification code:402.1 Industrial and Agricultural Buildings - 451 Air Pollution - 461.7 Health Care - 707 Illuminating Engineering - 741.1 Light/Optics - 913.3 Quality Assurance and Control
DOI:10.11975/j.issn.1002-6819.2015.11.033
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 9>
Accession number:20152701006220
Title:Matching design and performance analysis for driving system of solar garden tractor
Authors:Zhang, Chao (1); Zhu, Sihong (1); Wang, Junyang (1); Gao, Huisong (1); Deng, Xiaoting (1)
Author affiliation:(1) College of Engineering, Nanjing Agricultural University, Nanjing, China; (2) Jiangsu Key Laboratory for Intelligent Agricultural Equipment, Nanjing, China
Corresponding author:Zhu, Sihong
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:24-30
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Solar garden tractor not only drives tractor, but also does some garden works, and its driving system has unique requirement. A design method for driving system of solar garden tractor was put forward, which included the overall design and the main parameters of the theoretical calculation. Firstly, for the wheel drive mode's power transmission chain was short, and its driving and braking force distribution could be controlled and optimized by the energy management and power system, which was helpful to improve the drive system's efficiency, extend operation time and increase mileage, the wheel drive mode was therefore chosen as solar tractor drive system. Secondly, the components of solar tractor included the hub motor, the moving motor, the reducer, the battery pack and the photovoltaic panel. In order to evaluate solar tractor's working capacity, the cumulative operation time throughout day was proposed as the evaluation index. The cumulative operation time throughout day referred to the sum of solar tractor working time in a day after the battery was fully charged. According to the principle of solar tractor, i.e. obtained total energy is equal to consumed energy by the tractor, calculate the cumulative operation time throughout day. The obtained total energy by solar tractor was composed of photovoltaic panel output total energy throughout day and battery rated output energy. Based on a large number of test and analysis on solar radiation intensity and environment temperature on horizontal plane in Nanjing, solar radiation intensity model and environment temperature model were established under cloudless weather throughout the day to describe climate change. According to the parameters of photovoltaic panel, solar radiation intensity and environment temperature, the photovoltaic panel's P-V output characteristic curve was obtained, and based on the peak power of photovoltaic panel, total output energy values of 4 photovoltaic panels were calculated to be 2976 and 1 536 W·h in summer and winter, respectively. Taking the design of solar garden tractor as an example, and combined with the Nanjing regional hourly meteorological variation, the daily generating capacity was predicted using photovoltaic panels in different seasons, and the relationships between the speed of tractor and accumulated operation time throughout day were calculated under the ramp transportation operation, ramp grass cutting operation, horizontal transportation operation and horizontal grass cutting operation working conditions. The results showed that, with the increase of operating speed, the trend of cumulative operation time throughout day was shortened, which was due to the decrease of the actual battery discharge capacity with the increase of discharge current. Under the same conditions, the cumulative operation time throughout the day in summer was longer than in winter. When the speed was 3 km/h, for tractor horizontal grass cutting operation with solar, the accumulated operation time throughout day was 14.5 h, and for without solar the time was 9.5 h. When the speed was 3 km/h, for tractor ramp grass cutting operation with solar, the accumulated operation time throughout day was 5.9 h, and under the same speed without solar, the accumulated operation time throughout day was 3.8 h. It was obvious that using photovoltaic panels greatly extended the tractor's accumulated operation time throughout day, which indicated that photovoltaic cell as garden tractor energy was feasible and also could meet the need of gardening works. The research results can be used for solar garden tractor driving system design and optimization, and provide the basis for the development of solar garden tractor. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:27
Main heading:Solar power generation
Controlled terms:Climate change - Climate models - Computer systems - Design - Drives - Electric batteries - Electric power transmission - Molecular physics - Photoelectrochemical cells - Photovoltaic cells - Solar energy - Solar radiation - Speed - Tractors (agricultural) - Tractors (truck) - Wheels
Uncontrolled terms:Braking force distribution - Design and optimization - Gardening - Meteorological variation - Power transmission chain - Solar radiation intensity - Theoretical calculations - Transportation operations
Classification code:408 Structural Design - 443 Meteorology - 451 Air Pollution - 601.2 Machine Components - 657.1 Solar Energy and Phenomena - 663.1 Heavy Duty Motor Vehicles - 702.1 Electric Batteries - 705 Electric Generators and Motors - 706.1.1 Electric Power Transmission - 722 Computer Systems and Equipment - 723 Computer Software, Data Handling and Applications - 741.3 Optical Devices and Systems - 921 Mathematics - 931.1 Mechanics - 931.3 Atomic and Molecular Physics
DOI:10.11975/j.issn.1002-6819.2015.11.004
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 10>
Accession number:20152701006258
Title:Measurement of transportation resonance frequency and its influence on qualities of muskmelon during storage
Authors:Cheng, Xu (1); Yang, Xiaoqing (1); Dong, Tongliga (1)
Author affiliation:(1) College of Food Science and Engineering, Inner Mongolia Agricultural University, Huhhot, China
Corresponding author:Yang, Xiaoqing
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:294-299
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Muskmelons, a typical fruit with excellent flavor produced in northwest of China, are always harvested from late July to mid-August. At time of harvest, it floods the local market. Transportation and circulation of the muskmelon outside the area are common and trucks are the most usual and important tools for the product transportation and distribution. However, the fruits are easily injured during the transportation because they contain high percentage of water in their fresh forms and are continuing to ripen during transportation resulting from their physiological function through post-harvest respiration. Injure of fruits caused by vibration during long distance transportation manifest typically itself in two aspects. One lies in acceleration due to vibration caused by repeated low-stress fatigue damage, the other is the vibration at resonant frequency, which is a special case in the random vibration. Resonant frequency is mainly affected by the damping force, followed with the object shape, mass and firmness and widely known to be harmful in most mechanical systems but few reports have been published about its harmfulness in fruits transportation. In addition, how to measure the resonant frequency and to further improve the accuracy of random vibration analysis of fruits transportation have not been reported. This study was to investigate the resonant frequency and to improve the accuracy of random vibration analysis in the vibration process through simulating actual transportation situation by the use of both window function and transferring analysis on the platform of DASP software, which enhanced useful information in signals and weaken those useless ones. The window functions essentially referred to limit the scope of signal and observation time, and data must be windowed in order to minimize spectrum leakage. To maximize the credibility of the data processing results and minimize errors due to spectrum leakage, Hanning window of DASP software was used in the test with the number of analysis points greater than 8192 and overlapping coefficient 31/32. Resonant frequency of sample, which can be detected repeatedly through Hanning window functions, was the one when the maximum acceleration transferring rate was achieved during the whole sweep frequency process with a value of 35.38 Hz. Meanwhile, resonant frequencies of different ripeness groups of muskmelons with firmness of (7-8.2)×10<sup>5</sup>, (5.4-6.8)×10<sup>5</sup> and (4.1-5.2)×10<sup>5</sup> Pa were achieved respectively with the value of 41.8-45.5, 36.2-38.87 and 33.25-36.8 Hz, showing significant positive correlation between resonant frequency and firmness of muskmelons with a correlation coefficient 0.9132. The study of the impact of both resonant frequency vibration and low frequency vibration on the qualities, such as firmness, soluble solid content (SSC) and damage volume rate (DVR), was carried out as well as the prediction model during storage. The low frequencies of 4 and 6 Hz were adopted in the test according to survey of truck transportation profiles combining with characteristics of muskmelons at the speed of 50-70 km/h in northwest of China. Methods were respectively used to determine the firmness, SSC and DVR. The results showed that the qualities of muskmelons always deteriorated during storage after vibration with prolonging vibration time under any vibration frequency. As both the firmness and SSC decreased, the DVR sharply increased. In addition, the DVR caused by vibration of resonant frequency was obviously greater than that of low frequency in the condition of long lasting time. Multiple linear regression models using storage time and quality parameters obtained showed better correlation (R<sup>2</sup>>0.95). This study demonstrated the feasibility of detecting the resonant frequency during fruits transportation vibration using window functions and of predicting shelf life of muskmelons postharvest, and also provides basic foundation for appropriate package avoiding resonant frequency in real transportation conditions. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:23
Main heading:Vibration analysis
Controlled terms:Automobile testing - Data handling - Digital storage - Energy storage - Fatigue damage - Fruits - Harvesting - Linear regression - Mass transportation - Natural frequencies - Regression analysis - Software testing - Transportation - Truck drivers - Truck transportation - Trucks
Uncontrolled terms:Correlation coefficient - Hanning window functions - Low-frequency vibration - Multiple linear regression models - Muskmelon - Physiological functions - Random vibration analysis - Vibration
Classification code:421 Strength of Building Materials; Mechanical Properties - 431 Air Transportation - 431.2 Passenger Air Transportation - 432 Highway Transportation - 433 Railroad Transportation - 433.2 Passenger Railroad Transportation - 434 Waterway Transportation - 434.2 Passenger Waterway Transportation - 662 Automobiles and Smaller Vehicles - 663 Buses, Tractors and Trucks - 663.1 Heavy Duty Motor Vehicles - 702 Electric Batteries and Fuel Cells - 711.1 Electromagnetic Waves in Different Media - 722.1 Data Storage, Equipment and Techniques - 723.2 Data Processing and Image Processing - 723.5 Computer Applications - 821.3 Agricultural Methods - 821.4 Agricultural Products - 922.2 Mathematical Statistics - 943.2 Mechanical Variables Measurements - 951 Materials Science
DOI:10.11975/j.issn.1002-6819.2015.11.042
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 11>
Accession number:20152701006236
Title:Determination of drip tapes layout parameters for irrigation of sugarcane in latosolic red soil in Guangxi Autonomous Region
Authors:Huang, Kai (1); Cai, Desuo (1); Pan, Wei (2); Guo, Jinchuan (2)
Author affiliation:(1) School of Civil Engineering, Guangxi University, Nanning, China; (2) Guangxi Institute of Hydraulic Research, Nanning, China
Corresponding author:Cai, Desuo
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:136-143
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Surface drip irrigation is commonly used for efficient water-saving irrigation in latosolic red soil of sugarcane fields in Guangxi Autonomous Region, China. Selection of appropriate layout parameters of drip tapes for irrigation in latosolic red soil of sugarcane fields has rarely been studied and it is important to improve irrigation quality and water use efficiency. The objectives of this study were: 1) to analyze the effects of the main technical parameters of drip tapes on the soil water movement and change in soil water content under drip irrigation; 2) to summarize the basic requirements of appropriately determining the main technical parameters of drip tapes; 3) to determine the appropriate design parameters of drip tapes for irrigation in latosolic red soil of sugarcane fields based on project cost, project management and operation patterns, and water demand of sugarcane crop in different growth stages. To address the above objectives, representative latosolic red soil sample was collected from sugarcane field in Guangxi. First, a laboratory experiment of water movement with surface drip irrigation was performed in soil columns under irrigation conditions with different emitter discharge rates and emitter spacing (30 cm vs. 1.38 L/h, 40 cm vs. 2.20 L/h, and 50 cm vs. 2.80 L/h, respectively). Changes in the surface ponding radius, wetted surface radius and vertical wetted depth were monitored during the experiment. Then, the main parameters for model building were from the physical properties of the soil and the results of the experiment. A model of soil water movement under double-point source of drip irrigation was built using HYDRUS-3D. Next, the effects of emitter spacing and emitter discharge rate on irrigation uniformity were analyzed using the HYDRUS-3D model. Appropriate parameters ranges for drip irrigation were determined based on the results of model analysis. Further, irrigation uniformity, project cost, project management and operation, and water demand of sugarcane crop at different growth stages were taken into consideration to determine appropriate design parameters of drip tapes for irrigation in latosolic red soil of sugarcane fields in Guangxi. The results showed that: 1) The simulation results of the Hydrus-3D model of soil water movement were reliable as compared with the experimental data, indicating the reliability of the model used for the following study; 2) Emitter spacing was the primary factor affecting irrigation uniformity; at the emitter discharge rate of 1.38 L/h, drip tapes with the emitter spacing of 30 cm yielded higher irrigation uniformity, compared with the larger emitter spacing (40 or 50 cm); 3) At the same emitter spacing, irrigation uniformity was improved with the higher emitter discharge rate; At the emitter spacing of 40 cm, drip tapes the higher rate (2.20 or 2.80 L/h) resulted in the higher irrigation uniformity. Given the slow water infiltration in latosolic red soil, we recommended to use drip tapes with lower emitter discharge rate on the premise of meeting the requirement of irrigation uniformity. Taking into account of project cost, project management and operation patterns and water demand of sugarcane, we suggested optimal layout parameters of drip tapes in latosolic red soil of sugarcane fields in Guangxi: emitter discharge rate 1.38 L/h, emitter spacing 30 cm, irrigation duration in the early and vigorous growth stage of sugarcane 3.5 and 6.5 h. This study provides guidance for drip irrigation project design in sugarcane fields. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:29
Main heading:Irrigation
Controlled terms:Costs - Crops - Discharge (fluid mechanics) - Project management - Soil moisture - Soils - Sugar cane - Water conservation - Water supply - Wetting
Uncontrolled terms:Different growth stages - Drip irrigation - Drip irrigation projects - Emitter spacing - Irrigation uniformity - Main technical parameters - Surface drip irrigations - Water-saving irrigation
Classification code:407 Maritime and Port Structures; Rivers and Other Waterways - 444 Water Resources - 446.1 Water Supply Systems - 483.1 Soils and Soil Mechanics - 821.3 Agricultural Methods - 821.4 Agricultural Products - 911 Cost and Value Engineering; Industrial Economics - 912.2 Management - 931.2 Physical Properties of Gases, Liquids and Solids
DOI:10.11975/j.issn.1002-6819.2015.11.020
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 12>
Accession number:20152701006230
Title:Evaluation method for irrigation-water use efficiency based on principle component analysis and Copula function
Authors:Li, Haoxin (1); Shao, Dongguo (1); Yin, Xi (1); Chen, Shu (1); Xu, Baoli (1)
Author affiliation:(1) State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, China
Corresponding author:Shao, Dongguo
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:96-102
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Water use efficiency is an important parameter used for assessing quality of irrigation water system. This paper proposed a principle component analysis (PCA)-Copula method to comprehensively evaluate irrigation water use efficiency. Six indexes including water utilization coefficient of canal system, ratio of effective irrigated farmland, irrigation water use of unit area, water utilization coefficient of field, ratio of grain crop and yield of unit irrigation water were selected to estimate the water use efficiency. These indexes were normalized using mean and standard deviation. Two mutually independent principal factors were extracted from the normalized indexes by principal component analysis, and then incorporated into the Copula function to evaluate water use efficiency. Two mutually independent factors rather than six indexes decreased the dimension of copula function and thus overcame the difficulty of parameter estimation for multivariate copula. Five types of marginal distribution functions, i.e., Normal distribution, Exponential distribution, Extreme Maximum Type I distribution, Extreme Minimum Type I distribution and Gamma distribution, were used to fit the principal factors and Kolmogorov-Smirnov test was utilized for estimating the fitness of marginal distribution function. Finally, Akaike Information Criterion (AIC) and root-of-mean-square error (RMSE) were used for the selection of marginal distribution. Seven irrigation districts were chosen as the case study and the evaluation results of proposed PCA-Copula evaluation method were compared with those of Entropy Value Method (EVM) and Mutation Theory Evaluation Method (MTEM). The water use efficiencies of 7 irrigation districts were evaluated and ranked by the three methods, respectively. The results showed that the Spearman's rank coefficients between the results of PCA-Copula and those of EVM and MTEM were 0.857 and 0.75, respectively, which were above the threshold value of 0.714 and illustrated that the results of PCA-Copula method is consistent with those of EVM and MTEM. And the correlation coefficients between the effective irrigation water utilization coefficient and the results based on the PCA-Copula method, EVM and MTEM were 0.875, 0.875 and 0.768, respectively, revealing that the PCA-Copula method and EVM are superior over MTEM. In addition, the value of water use efficiencies evaluated by PCA-Copula method was evenly distributed over [0, 1] with the difference between maxima and minima of 0.622, rather than concentrated near 0.1 (the difference between maxima and minima of 0.037 based on EVM) or 1 (the difference between maxima and minima of 0.024 based on MTEM), implying a higher resolution ratio of PCA-Copula method over the other two methods. Therefore, the PCA-Copula method can assess the irrigation water use efficiently and lead to great convenience to the practice of water resources management. The water use efficiencies of 7 irrigation districts have been all increased by adopting water saving irrigation. By using the proposed method, water use efficiency was highest and greatly improved by water saving strategy in Zhanghe irrigation district, followed by Dujiangyan district. And, the water use efficiency and improvement of Zekou district and Shimen district were relatively low, only better than Dongfeng district, Yahekou district and Pingyuan district. In addition, Partial correlation analysis was used between water use efficiency evaluation based on PCA-Copula method and irrigation scale, precipitation and irrigation cost and the results implied: 1) water use efficiency was increased with increasing irrigation scale; 2) water use efficiency was low for the area with high precipitation; and 3) water use efficiency increased with increasing irrigation cost. These implications can be used for the adjustment of water resources management policies. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:34
Main heading:Water resources
Controlled terms:Correlation methods - Cost benefit analysis - Distribution functions - Efficiency - Function evaluation - Irrigation - Mean square error - Normal distribution - Principal component analysis - Subirrigation - Water - Water conservation - Water supply
Uncontrolled terms:Akaike information criterion - Comprehensive evaluation - Copula functions - Irrigation water use efficiency - Mean and standard deviations - Principle component analysis - Water resources management - Water use efficiency
Classification code:444 Water Resources - 446.1 Water Supply Systems - 821.3 Agricultural Methods - 911 Cost and Value Engineering; Industrial Economics - 913.1 Production Engineering - 921.6 Numerical Methods - 922.1 Probability Theory - 922.2 Mathematical Statistics
DOI:10.11975/j.issn.1002-6819.2015.11.014
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 13>
Accession number:20152701006250
Title:Seedling effects of corncob and bagasse composting substrates in cucumber
Authors:Zhang, Shuo (1); Yu, Hongjun (1); Jiang, Weijie (1)
Author affiliation:(1) Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
Corresponding author:Jiang, Weijie
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:236-242
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The aim of this study was to obtain the optimum proportion of peat and vermiculite to composted corncob/bagasse for a good growing media in cucumber seedling. The corncob was common in the north of China, while the bagasse was common in the south of China. This experiment studied the influence of the physical and chemical properties of different treatments on cucumber seeding. Four treatments were set with corncob: T1 (all was corncob), T2 (corncob: vermiculite=1:1, v/v), T3 (corncob: peat=1:1, v/v) and T4 (corncob: vermiculite: peat=1:1:1, v/v). Bagasse was also used to set 4 treatments: T5 (all was bagasse), T6 (bagasse: vermiculite=1:1, v/v), T7 (bagasse: peat=1:1, v/v) and T8 (bagasse: vermiculite: peat=1:1:1, v/v). And we took 'Zhongnong 26' cucumber (Cucumis sativus L.) as experimental material and traditional commercial substrate as control. The experiment was carried out in the greenhouse of Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences from September to October in 2014.The parameters included bulk density, pH, electrical conductivity (EC), total porosity, water holding capacity, air filled porosity and nutrition content of different substrates, and cucumber height, stem diameter, ground fresh weight, ground dry weight, underground fresh weight, underground dry weight and seedling index. Bulk density, porosity and nutrition were determined by the methods of Bao and Lian. The pH value and EC were determined by IQ150 Portable pH/mV/thermometer measurement. The parameters of cucumber were determined by conventional method. The results indicated that: T4 and T6 could meet the requirement of cucumber seedling culture. The cucumber heights of T4 and T6 were 15.06 and 22.17 cm, respectively. The stem diameters of T4 and T6 were 4.03 and 3.97 mm, respectively. The ground fresh weights of T4 and T6 were 5.01 and 4.63 g, respectively. The dry weights of T4 and T6 were 0.94 and 1.19 g, respectively. T4 and T6 had a significant influence on the height and stem diameter of cucumber, which were better than the control. And the ground fresh weights and ground dry weights of T4 and T6 had no significant difference with the control. The underground fresh weights of T4 and T6 had no significant difference with the control, but T4 and T6 were significantly better than any other treatment. T6 had no significant difference on underground dry weight compared with the control. And the seedling index of T6 had no significant difference with the control. The seedling index of T4 had significant difference with the control (P<0.05), and was better than any other treatment which included corncob (P>0.05). The comprehensive evaluation coefficient of T6 was better than any other treatment and control. The comprehensive evaluation coefficient of T4 was better than any other treatment which included corncob, and there was no obvious difference between T4 and control. So we concluded that T4 and T6 were horticulturally acceptable as an alternative to commercial substrate for cucumber seedling culture. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:26
Main heading:Substrates
Controlled terms:Bagasse - Cloud seeding - Forestry - Growth (materials) - Nutrition - Peat - Porosity - Suspensions (fluids) - Wastes
Uncontrolled terms:Air-filled porosities - Comprehensive evaluation - Corncob - Cucumber - Electrical conductivity - Experimental materials - Physical and chemical properties - Water holding capacity
Classification code:443.3 Precipitation - 452.3 Industrial Wastes - 461 Bioengineering and Biology - 461.7 Health Care - 503 Mines and Mining, Coal - 524 Solid Fuels - 801 Chemistry - 804 Chemical Products Generally - 811 Cellulose, Paper and Wood Products - 821.0 Woodlands and Forestry - 931.2 Physical Properties of Gases, Liquids and Solids - 951 Materials Science
DOI:10.11975/j.issn.1002-6819.2015.11.034
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 14>
Accession number:20152701006239
Title:Effects of different grade drought on grain yield of spring maize in Northern China
Authors:Dong, Chaoyang (1); Liu, Zhijuan (1); Yang, Xiaoguang (1)
Author affiliation:(1) College of Resources and Environmental Science, China Agricultural University, Beijing, China; (2) Tianjin Climate Center, Tianjin, China
Corresponding author:Yang, Xiaoguang
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:157-164
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Maize planting in northern region of China plays a vital role in the crop production in China, and it occupies a large proportion in total grain production and planting area in China. Meanwhile, northern region of China is prone to drought and the drought normalization happens in this area seriously, which restricts the steady development of maize. The data used in this paper included daily weather data of 217 meteorological stations in the 14 provinces (municipalities, or autonomous regions) in northern region of China from 1961 to 2010 and crop, soil, field management data of spring maize. Based on the total precipitation during the growing season of spring maize we divided the study area into 6 precipitation zones (I-VI) with the interval of 100 mm, and then analyzed the effects of drought of different grades occurring in main growing stage on grain yield of spring maize in northern region of China by using the crop water deficit index as the agricultural drought index and the agriculture production systems simulator (APSIM) as the research method. The results showed that the yield reduction of spring maize caused by drought in northern region of China had a decreasing trend from west to east, and the precipitation distribution led to the differences of damage degree in each area directly. The precipitation during growing season of spring maize in Zone I located in western region (including Xinjiang, western Inner Mongolia and northern Gansu) was below 100 mm, and the natural precipitation couldn't meet the need of growth and development of spring maize, so the drought risk of planting spring maize under rainfed conditions in western oasis irrigated agricultural area was great, and it needed to energetically develop water-efficient irrigation in this area. While the precipitation during growing season of spring maize in Zone VI located in southeastern region (including Southern Jilin, eastern Liaoning, southern Henan and southern Shaanxi) was above 500 mm, and the natural precipitation could meet the requirements of spring maize growth and development basically, so production in eastern rainfed agricultural area would be less affected by drought, and it was difficult to reflect the influence of drought grade difference on production accurately. In addition, the ratio of the station with yield reduction had a decreasing trend with the increasing of yield loss degree; from jointing to tasselling stage, the yield reduction in northern region of China was between 0 and 50%, and there were 37.3% of stations with the yield reduction of between 0 and 10%, and only 4.1% of stations with the yield reduction of between 40% and 50%. Drought happening from jointing to tasselling stage of spring maize will cause serious influence on grain yield, and the yield reduction in this stage is higher than that from tasselling to maturity stage. Besides, the discrete degree of yield reduction in this stage is also higher than that from tasselling to maturity stage. The influence degree of drought of each grade on crop production is different; from jointing to tasselling stage, the interquartile ranges of yield reduction caused by drought are extreme drought (20.1%-33.6%), severe drought (12.0%-20.3%), moderate drought (6.3%-15.2%) and light drought (4.7%-11.6%), respectively. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:45
Main heading:Drought
Controlled terms:Agriculture - Crops - Cultivation - Grain (agricultural product) - Meteorology - Models
Uncontrolled terms:Agriculture productions - Field management data - Grain yield - Growth and development - Meteorological station - Northern China - Precipitation distribution - Spring maize
Classification code:443 Meteorology - 444 Water Resources - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 902.1 Engineering Graphics
DOI:10.11975/j.issn.1002-6819.2015.11.023
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 15>
Accession number:20152701006245
Title:Progressive approach for risk prediction of rangeland locust hazard in Xinjiang based on remotely sensed data
Authors:Zhang, Xianfeng (1); Rao, Junfeng (1); Pan, Yifan (1)
Author affiliation:(1) Institute of Remote Sensing and GIS, Peking University, Beijing, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:202-208
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Locust hazard is one of the major disasters for farming and animal husbandry in Xinjiang, China. Currently locust disaster monitoring mainly relies on the limited observatory field sites and is not efficient due to Xinjiang's remote geographic location, vast area and inadequate technological support. Fortunately, remote sensing technique offers a valuable tool for locust hazard monitoring and prediction in a large area such as Xinjiang. This study presents a progressive modeling approach for locust hazard risk prediction of the rangeland in Xinjiang. The underlying thought is that the model is to be built based on the key 3 growth stages of locust, namely oviposition, incubation and development, and these processes are heavily affected or even determined by the locust habitats which can be resolved into some key ecological and environmental factors, such as land surface/air temperature, rainfall, soil moisture, soil type, vegetation type and coverage, geographic altitude. The suitability of locust habitat is assessed for these 3 stages using satellite remote sensing data, adopting locust oviposition suitability indicator (OSI), incubation suitability indicator (ISI) and development suitability indicator (DSI). The 3 types of suitability indicators are created mainly based on the derivatives from Terra/MODIS remote sensing data, digital elevation model (DEM) data and ground measured ancillary data. The OSI is created by the weighted combination of 3 sub-indices: soil type factor, soil moisture factor and vegetation factor for oviposition. The ISI is formed from the multiplication of land surface temperature factor and soil moisture factor. And geographic altitude factor, vegetation coverage factor in development stage and vegetation type factor are used to generate the DSI by a weighted combination. Each factor is normalized to the score from 1 to 10, indicating the degree of suitability of this factor. The number 1 represents least suitability and 10 most suitability. Afterwards, the 3 indicators OSI, ISI and DSI are incorporated into locust risk index (LRI) in a multiplicative manner, which is used as a quantitative index to assess the locust hazard risk spatially. The historical data of locust hazard and in-situ measurement data of locust density in 2014 are used to calibrate the model, and consequently the resultant LRI can be further classified into 4 risk levels: low, low-moderate, moderate-high, and high when LRI is less than 100, >100-200, >200-300 and greater than 300, respectively, which can be empirically used to represent the potential severity of locust disaster in the next few months. Considering the variations and interannual fluctuation, a progressive strategy is proposed and incorporated into the modeling process. Two types of modification are applied to the primary model prediction, i.e. oviposition modification and third-instar modification. This strategy allows to making use of the dynamic data acquired by satellite remote sensors, and periodically updates the habitat factors input of the model through quantitative inversion of remotely sensed data. Therefore, the modeled LRI can better reflect the incoming locust hazard possibility and provide more accurate prediction than conventional single input-output model run. The model is subsequently utilized to assess and predict the risk of the locust hazard in the rangeland of Xinjiang in 2010 and 2014. The result indicates that the proposed progressive strategy for the locust hazard risk can reflect the variability of the key habitat factors that affect the locust population development. It also shows that the progressive approach can avoid inaccuracy of one-time prediction, and the modeled results are well correlated to the actual locust hazard severity degree which is classified based on the in-situ measurements of locust density. On the basis of the validation between the modeled risk levels and in-situ measured locust disaster severity classes, the results indicate that approximately 74.4% of the sample sites are completely fallen into the same level, and 94.9% of the samples are different within one level. Thus, the model is useful for early warning of locust hazard and the disaster prevention and relief in Xinjiang area. The model can also be localized and applied in other arid areas of the world. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:22
Main heading:Risk assessment
Controlled terms:Arid regions - Atmospheric temperature - Disaster prevention - Disasters - Ecosystems - Forecasting - Hazards - Moisture - Pest control - Remote sensing - Soil moisture - Soils - Surface measurement - Surveying - Vegetation
Uncontrolled terms:Digital elevation model - Habitat factors - Interannual fluctuations - Land surface temperature - Quantitative retrieval - Remote sensing techniques - Satellite remote sensing data - Technological supports
Classification code:405.3 Surveying - 443 Meteorology - 443.1 Atmospheric Properties - 444 Water Resources - 454.3 Ecology and Ecosystems - 483.1 Soils and Soil Mechanics - 731.1 Control Systems - 803 Chemical Agents and Basic Industrial Chemicals - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 914.1 Accidents and Accident Prevention - 921 Mathematics - 943.2 Mechanical Variables Measurements
DOI:10.11975/j.issn.1002-6819.2015.11.029
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 16>
Accession number:20152701006242
Title:Simulated runoff processes on colluvial deposits of Liantanggang Benggang and their water distributions
Authors:Liu, Xilin (1); Tang, Chuan (2); Zhang, Dalin (1)
Author affiliation:(1) School of Geography and Planning, Sun Yat-sen University, Guangzhou, China; (2) State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:179-185
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Slope runoff of colluviums is the premise for gully runoff erosion, and is the main mode of the sheet-flow erosion in Benggang basin. Studies on characteristics of slope runoff and sediment transportation mechanism in Benggang basin are important for understanding Benggang erosion process and for erosion prevention and control. In this study, an artificial rainfall simulation experiment was carried out in field to investigate the slope runoff process and soil moisture distribution in Benggang basin. Liantanggang Benggang in Wuhua County of Guangdong Province was taken as the study area. In this area, 7 different colluvial deposits were selected including old and new deposits. The 7 deposits had slope of 4°-48°. The old deposits were developed for more than 5 years with dark color and the new deposits were less than 5 years with pale red color. In general, the structure was more stable in the old deposits than the new deposits. These 7 deposits were used for observations of runoff time under the artificial rainfall simulation. A portable rainfall simulator was used with rainfall duration from 0.6 to 60 min and rainfall amount from 2.4 to 60 mm. A total of 28 simulated rainfall experiments were preformed in the field, and the runoff time as well as soil moisture were observed and measured. The results showed that: 1) A negative power function could describe the relationship between the rainfall intensity and slope runoff (P<0.01), and the runoff time decreased rapidly with the increase of rainfall intensity; 2) A negative logarithmic function could reveal the relationship between runoff time and initial soil water content in depth of 10 cm for the old colluviums; 3) Based on the initial soil water content and rainfall intensity, the 3D surface model may be used to estimate the runoff time of the colluviums; 4) When the rainfall intensity reached 3.5 mm/min or above, the runoff time showed a linearly negative correlation with the slope of the colluviums, and the runoff time became shorter with increasing slopes. 5) After runoff of the colluviums, soil moisture was obviously different between the old and new deposits at the depth of 10 cm, and the soil moisture was over 20% in the old colluviums, and less 20% in the new colluviums; and 6) In the end of precipitation and after 24 h of rainfall, the wetting depth of the new colluviums were higher than that of the old colluviums, indicating that the instable depth of the new colluviums is larger than that of the old colluviums when rainfall occurs. The results provide rich information for understanding slope runoff process and method for erosion forecast in Benggang basin. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:11
Main heading:Runoff
Controlled terms:Deposits - Erosion - Moisture - Precipitation (meteorology) - Rain - Soil moisture - Soils - Water supply systems
Uncontrolled terms:Artificial rainfall simulations - Artificial simulation - Benggang - Colluvial deposits - Logarithmic functions - Negative correlation - Slope - Soil moisture distribution
Classification code:407 Maritime and Port Structures; Rivers and Other Waterways - 443.1 Atmospheric Properties - 443.3 Precipitation - 444.1 Surface Water - 446.1 Water Supply Systems - 483 Soil Mechanics and Foundations - 483.1 Soils and Soil Mechanics - 532 Metallurgical Furnaces - 612 Engines - 617 Turbines and Steam Turbines
DOI:10.11975/j.issn.1002-6819.2015.11.026
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 17>
Accession number:20152701006226
Title:Analytical methods and verification for determining slip factor at impeller outlet of centrifugal pumps as turbines
Authors:Shi, Guangtai (1); Yang, Junhu (2); Miao, Senchun (2)
Author affiliation:(1) School of Energy and Power Engineering, Xihua University, Chengdu, China; (2) School of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou, China
Corresponding author:Yang, Junhu
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:66-73
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:A centrifugal pump can be operated in its reverse rotational direction as a turbine-a prime motor, and its impeller is a kind of centripetal impeller. It can convert the high pressure energy of a fluid into the rotational mechanical energy of the rotor to drive a generator to generate electricity or drive a working machine, realizing an energy recycling of the high pressure fluid. It is well-known that the slip phenomenon exists in turbomachinery, such as hydraulic turbine, steam turbine, roto-dynamic pumps and compressors. This is also true for a centrifugal pump as turbine. The slip velocity may be smaller in a hydraulic turbine than a centrifugal pump. However, this is not the case for a centrifugal pump as turbine because its number of blades is much less compared with the hydraulic turbine. The constraint ability of blade is less for fluid giving rise a smaller slip factor. In addition, a slip factor is the key parameter to estimate the turbine output power based on its existing geometry and designed flow condition to check if its output power has met the requirement by end-users. Unfortunately, this topic is not well documented currently. In this paper, we put forward an analytical method to accurately determine the slip factor at the impeller outlet in a centrifugal pump as turbine in order to predict the turbine performance correctly. Firstly, the relative eddy flow in an impeller passage with closed inlet and outlet was analyzed for a centrifugal pump in its turbine mode. Secondly, three assumptions were made for the induced velocity by the eddy on the blade pressure side, then the slip velocities and the corresponding slip factors at the impeller outlet under these assumptions were derived analytically. Finally, the slip factor formulas were validated by means of the theoretical heads of ten centrifugal pumps as turbines based on their experimental data. Two cases, namely, the slip factors at both impeller inlet and outlet, and the slip factor at the impeller outlet alone, were studied, respectively. It was identified that the slip factor formula based on the second assumption, in which the ratio of the induced velocity on the blade pressure side over the slip velocity on the impeller outlet was equal to the ratio of the areas of two triangles with the pressure side and impeller outlet as one curved edge respectively, was subject to a very good accuracy. Moreover, it was unnecessary to include the slip factor at the impeller inlet when predicting the theoretical head of a pump as turbine. The influence factors of the slip on the centripetal impeller outlet of hydraulic turbine have the entrance and outlet diameter of impeller, entrance and outlet blade angle of blade and the number of blades. The research results improved the accuracy for predicting the performance of hydraulic turbine by the theoretical method, and this kind of method will be convenient and efficient when scholars predict the performance of hydraulic turbine, and may save the cost of research. The results provide a base for more accurately predicting the performance of a pump as turbine by making use of analytical methods. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:24
Main heading:Turbine components
Controlled terms:Centrifugal pumps - Digital storage - Flow measurement - Forecasting - Hydraulic machinery - Hydraulic motors - Hydraulic turbines - Impellers - Pumps - Steam turbines - Turbomachine blades - Velocity
Uncontrolled terms:Generate electricity - High-pressure fluids - Pump as turbine - Relative eddy - Rotational directions - Slip factor - Theoretical head - Theoretical methods
Classification code:601.2 Machine Components - 617 Turbines and Steam Turbines - 618.2 Pumps - 632.2 Hydraulic Equipment and Machinery - 722.1 Data Storage, Equipment and Techniques - 921 Mathematics - 931.1 Mechanics - 943.2 Mechanical Variables Measurements
DOI:10.11975/j.issn.1002-6819.2015.11.010
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 18>
Accession number:20152701006246
Title:Three-dimensional reconstruction and its precision evaluation of plant architecture based on multiple view stereo method
Authors:Hu, Pengcheng (1); Guo, Yan (1); Li, Baoguo (1); Zhu, Jinyu (2); Ma, Yuntao (1)
Author affiliation:(1) College of Resources and Environmental Sciences, China Agricultural University, Beijing, China; (2) Institute of Vegetables and Flowers, Chinese Academy of Agricultural Science, Beijing, China
Corresponding author:Ma, Yuntao
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:209-214
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Plant architecture is an important determinant of the canopy light interception and photosynthesis. Therefore, effective and nondestructive methods for obtaining plant architecture can help us understand the relationships between plant physiological processes and morphogenesis. Digital camera technology has become relatively ubiquitous and inexpensive, leading to a recent surge in utilizing plant imaging to capture data. Therefore, a three-dimensional (3-D) reconstruction of plant architecture based on these photographed image sequences can be realized. However, the accuracy evaluation of reconstruction is always determined from visual effect and or from 1-D or 2-D measured data. In this study, image sequences were obtained around experimental plants (e.g. egg plant, sweet pepper and cucumber) by slightly moving a commercial camera for image generation so that each neighboring image pair shared short baseline. Structure from motion (SFM) method was applied to produce a set of sparse point cloud based on plant image sequences. As the sparse point cloud was inadequate for the reconstruction of complicated plant architecture, multiple-view stereo (MVS) method was further used to produce dense and accurate point cloud based on the output of SFM. Software Bundler and CMVS were applied to implement the SFM and MVS methods, respectively. Bundler takes a set of images as input, and produces a 3D reconstruction of sparse scene geometry and camera parameters as output. CMVS takes a set of images and camera parameters (the output of Bundler) as input, and outputs a set of dense points with geometry details. Once original point cloud has been obtained, point cloud processing procedures were conducted to refine point cloud, including deleting noise points and scaling to the actual size of experimental plants. In order to obtain point cloud of individual blade, segmentation of point cloud of plants was conducted based on region growing segmentation algorithm. Once point cloud of individual blade was obtained, Poisson surface reconstruction algorithm was used to reconstruct each leaf. Before accuracy evaluation, point cloud of individual leaf blade and corresponding laser scanning point cloud were aligned to the same 3-D coordinate system using the Iterative Closest Point algorithm. Then, comparison on 3-D scale based on Hausdorff distance was made between point cloud data obtained from plant image sequences and referenced point cloud data with laser scanning on individual leaf blade level. Furthermore, phenotypic attributes, such as leaf blade width, leaf blade length and blade area were extracted based on data from image sequences and from laser scanning methods. Besides, these attributes of each blade were manually measured. Finally, comparisons were made for blade area, blade length and blade maximum width between data from the image sequence-based model, laser scanning based model and manually measured data. The results showed that high accuracy of 3-D reconstruction was obtained based on plant image sequence method. Hausdorff distances of experimental plants were ranged from 0 to 10 mm, and most of the values were less than 4.0 mm. There was a good agreement between measured and calculated blade area, blade length and maximum width with R<sup>2</sup>>0.95 for blade area, RMSE<4.5 mm for blade width, and RMSE<5.6 mm for blade length. There was no significant difference for each attribute between measured and calculated data (ANOVA, P>0.05). A key advance of the current 3-D reconstruction of plant architecture is the capability to non-destructively capture plant traits with high accuracy. This advance permits time-series measurements that are necessary to follow the progression of growth and stress on individual plants, and will play an important role in related research fields, such as plant phenotyping, genetic breeding, interactions between plant phenotype and environment. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:34
Main heading:Stereo image processing
Controlled terms:Algorithms - Computer vision - Geometry - Image processing - Image reconstruction - Image segmentation - Iterative methods - Laser applications - Pilot plants - Scanning - Stereo vision - Surface analysis - Surface reconstruction
Uncontrolled terms:Image sequence - Iterative closest point algorithm - Multiple views - Plant phenotyping - Surface reconstruction algorithms - Three dimensional - Three-dimensional (3-D) reconstruction - Three-dimensional reconstruction
Classification code:402.1 Industrial and Agricultural Buildings - 423 Non Mechanical Properties and Tests of Building Materials - 741 Light, Optics and Optical Devices - 744.9 Laser Applications - 921 Mathematics - 921.6 Numerical Methods - 951 Materials Science
DOI:10.11975/j.issn.1002-6819.2015.11.030
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 19>
Accession number:20152701006255
Title:Monitoring effects of ecosystem restructuring project for returning grain plots to forestry in Wuchuan county of Inner Mongolia based on RS and GIS
Authors:Wang, Fangtian (1); An, Pingli (1); Cai, Lujia (1); Huang, Xinxin (1); Hao, Jinmin (1)
Author affiliation:(1) College of Resources and Environmental Sciences, China Agricultural University, Beijing, China
Corresponding author:An, Pingli
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:269-277
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In order to monitor effects of ecosystem restructuring project under the government Grain for Green program, this paper, based on the MODIS NDVI time series data and land use change data, explored the regional land use change and consequently vegetation coverage change in Wuchuan county, Inner Mongolia, by using linear regression and remote sensing interpretation. Results showed that from 2000 to 2013, the annual maximum NDVI of study area was not improved progressively at all. But the vegetation coverage change of the whole area showed obvious spatial difference, the vegetation coverage with significant (P<0.05) increase accounted for 33.55% of the total study area, while significant (P<0.05) decrease of vegetation cover area was 30.15%, and the degraded area of the whole area mainly distributed in the northeast of Wuchuan county. The results also showed that from 1999 to 2010, generally speaking, the area of cultivated land in the studied area decreased by 18809.29 h<sup>2</sup>, which was mainly distributed in slope between 2° and 15° or altitude between 1500 m and 2000 m above sea level, and the proportion of returning farmland to forest and grass increased with slope and altitude within certain range. Overall a majority of steep slope land had been returned to forest and grass. Compared with 1999, there were 13873.48 hm<sup>2</sup> of the cultivated land converted to grassland, and at the same time, 5429.81 hm<sup>2</sup> of cultivated land converted to forests. In addition, in the area under Grain for Green program, the areas with degraded vegetation coverage accounted for 20.98%, and those with improved vegetation coverage accounted for 43.89%. In the area without the program, the areas with degraded vegetation coverage accounted for 29.34%, and the percentage of areas with improved vegetation coverage was 34.12%. In all, the vegetation coverage of the area under the program has been better than the area without the program since 2000.Last, from the specific land use change type, in the area under the program, the vegetation coverage of grassland returned from cropland experience improvement, the improved areas and degraded areas accounted for 34.65% and 30.45% of the total area in "cropland-grass" area. The degradation area is 4224.20 hm<sup>2</sup>, and mainly distributed in slope between 2°and 15° slope or altitude between 1500 m and 1750 m. By contrast, both of the vegetation coverage of forest returned from grassland and cropland experienced great improvement, and the improved proportions respectively accounted for 49.39% of the "cropland-forest" area and 51.14% of the "grass-forest" area. Among which, the improved areas of the forest returned from cultivated land mainly distributed in slope between 2° and 6° or altitude between 1500 m and 1750 m, and the improved areas of forest returned from grass mostly located in slope between 6°and 15°or altitude between 1750 m and 2000 m. Furthermore, in non-ecological area, vegetation coverage of the areas in "cropland-cropland" region, "forest-forest" region and "grass-forest" region experienced great improvement, the proportions of vegetation coverage improved areas among these land use type changes were separately 38.48%, 46.14%, 38.80%. While in other regions of non-ecological area, the vegetation coverage of the areas in "grass-grass" region, "grass-cropland" region and "grass-sand" region degraded markedly, and the proportions of degraded areas among those land use type changes were separately 31.06%, 35.79%, 62.61%. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:30
Main heading:Land use
Controlled terms:Ecology - Ecosystems - Forestry - Geographic information systems - Monitoring - Rain - Remote sensing - Sea level - Vegetation
Uncontrolled terms:Cover - Degradation areas - Grain for green projects - Monitoring effect - Remote sensing interpretation - Spatial differences - Vegetation coverage - Wuchuan county
Classification code:403 Urban and Regional Planning and Development - 443.3 Precipitation - 454.3 Ecology and Ecosystems - 471.1 Oceanography, General - 723.3 Database Systems - 731.1 Control Systems - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 821.0 Woodlands and Forestry - 941 Acoustical and Optical Measuring Instruments - 942 Electric and Electronic Measuring Instruments - 943 Mechanical and Miscellaneous Measuring Instruments - 944 Moisture, Pressure and Temperature, and Radiation Measuring Instruments
DOI:10.11975/j.issn.1002-6819.2015.11.039
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 20>
Accession number:20152701006218
Title:Design and experiment on critical component of cultivator for straw returning in paddy field and dry land
Authors:Zhang, Xiumei (1); Zhang, Jumin (1); Xia, Junfang (1); Zhang, Shun (1); Zhai, Jianbo (1); Wu, Hao (1)
Author affiliation:(1) College of Engineering, Huazhong Agricultural University, Wuhan, China; (2) College of Mechanical Engineering, Wuchang Institute of Technology, Wuhan, China
Corresponding author:Xia, Junfang
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:10-16
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:As the main producing area of rice, the Yangtze River basin usually had various multiple cropping systems, such as rape-rice, wheat-rice, green manure-rice, the double cropping of rice, triple-cropping. Rice is planted immediately after the harvest of the previous crop. So the straws are buried in the field in a busy harvesting and planting season. Crop residues incorporated in farmland by mechanical technique can improve soil physics properties and fertility, increase the yield and farm income. Straw returning to field practice can reduce the problem of crop residue burning and also the amount of chemical fertilizer application. Based on our previous research on the 1GMC-70, the cultivator for high stubble returning in paddy field, a new roller of cultivator for straw returning both in paddy field and dry land was designed. The helical rotary blades, bent blades and the IIT245 rotary blade were the main tillage parts of the machine, and its power consumption was an important technical parameter to consider for the overall performance. The former two types of blade are used to cut soil, while the latter one to bury straw. In this study, based on the roller structural and working principle of the main parts of the cultivator, the parameters of key components were tested for the rotary blades IIT245 and spiral blades. Furthermore, their interrelationships and interactions were analyzed in detail. An advisable arrangement of rotary blades IIT245 fixed on the rotor was provided. The tillage width was 2000 mm. The rotor speed was 335 rev/min. The forward velocity was 0.7 to 1.1 m/s. The lower forward velocity was used in dry land, while the higher forward velocity was for wet land tillage. Experiments of crop straw burying rotary tillage were conducted repeatedly both in wet land and dry land. The field test showed when tillage in fields of soil compaction value under 1260 kPa at about 150 mm depth, the cultivator could realize the straw mulching and returning, soil crashing, and surface leveling at the same time. In details,, in the dry land and paddy field, the tillage depth of this cultivator was 151.2-173.8 mm and 181.6-200.4 mm, stability of tillage depth was 92.4%-93.4% and 92.4%-94.8%, field surface roughness was less than 12 mm, vegetation coverage rate was 90.6%-97% and 96.3%-96.4%, and soil crushing rate was 64.5%-90.2% and 87.3%-89.6%. The field test indicated that the cultivator possessed both the advantages of traditional rotary tiller for soil tillage and the developed products by our research group for high straw burying. The advantages included wide tillage width, deep tillage depth, high straw burying rate, high operational efficiency, easy tillage operation. In addition, it could also cut down on tillage time and save labors, which showed great superiority in the field of the straw returning back to farmland machine. Results of the research indicate the working qualities of cultivator met the agro-technical requirement of rice and wheat sowing and transplanting. It was suitable for tillage in middle and lower reaches of Yangtze River, where the principal crop rotation was wet land rice after dry land crop annually. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:23
Main heading:Agricultural machinery
Controlled terms:Agricultural wastes - Agriculture - Crops - Cultivation - Design - Farms - Fertilizers - Machine design - Manures - Rollers (machine components) - Soil mechanics - Soil testing - Soils - Straw - Surface roughness - Turbomachine blades
Uncontrolled terms:Crop residue burning - Dry land - Middle and lower reaches of yangtze rivers - Multiple cropping systems - Operational efficiencies - Roller - Soil tillage - Technical requirement
Classification code:408 Structural Design - 483.1 Soils and Soil Mechanics - 601 Mechanical Design - 601.2 Machine Components - 618 Compressors and Pumps - 804 Chemical Products Generally - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 931.2 Physical Properties of Gases, Liquids and Solids
DOI:10.11975/j.issn.1002-6819.2015.11.002
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 21>
Accession number:20152701006235
Title:Improvement of Hargreaves method for reference evapotranspiration in hilly area of central Sichuan Basin
Authors:Li, Chen (1); Cui, Ningbo (1); Wei, Xinping (1); Hu, Xiaotao (3); Gong, Daozhi (4)
Author affiliation:(1) State Key Laboratory of Hydraulics and Mountain River Engineering & College of Water Resource and Hydropower, Sichuan University, Chengdu, China; (2) Provincial Key Laboratory of Water-Saving Agriculture in Hill Areas of Southern China, Chengdu, China; (3) Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F University, Yangling, China; (4) State Engineering Laboratory for Efficient Water Use and Disaster Loss Reduction of Crops, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agriculture Science, Beijing, China
Corresponding author:Cui, Ningbo
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:129-135
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Reference crop evapotranspiration (ET<inf>0</inf>) is an important part of water cycle and water balance. Accurate estimation of ET<inf>0</inf> becomes vital in planning and optimizing irrigation schedules and irrigation systems management. Numerous methods have been proposed for estimating ET<inf>0</inf>, among which Penman-Monteith (P-M) model recommended by Food and Agriculture Organization of the United Nations (FAO) in 1998 since it provids the highest accurate results across the world wherever in an arid or humid environment. But the main problems computing ET<inf>0</inf> by P-M model are its complicated nonlinear process and requirements of many climatic variables. Thus, there is an urgent need to develop a much simpler and more appropriate model in areas with limited data, such as the Hargreaves-Samani (HS) method, which is modified in this paper. In order to obtain more accurate HS model of ET<inf>0</inf> in hilly area of central Sichuan Basin, 3 parameters (including temperature index, temperature coefficient and temperature constant) were calibrated based on Bayesian Theory using daily meteorological data from 1953 to 2002. Then, the daily and monthly ET<inf>0</inf> from 2003 to 2013 were computed by the modified HS model, original HS model and PM model. Compared with the value recommended by FAO (the temperature index, temperature coefficient and temperature constant are 0.0023, 0.5 and 17.8, respectively), the 3 parameters obtained from the modified HS model were much smaller, and increased by latitude (0.00213, 0.46 and 16.5 in north zone, 0.00217, 0.44 and 16.36 in central zone, 0.00212, 0.44 and 16.21 in south zone). The ET<inf>0</inf> calculated by PM model was taken as the standard, the relative error of modified HS model decreased form 14.2%-60.9% to -1.1%-33.4% in north, 40.6%-92.6% to 16.9%-61.1% in central, 31.3%-96.0% to 8.5%-64.4% in south, and 32.1%-82.7% to 9.5%-52.6% in whole hilly area of central Sichuan Basin. Through the correlation analysis, the slope of regression curve between ET<inf>0</inf> calculated by PM model and ET<inf>0</inf> calculated by modified HS model were 1.16 in north (R<sup>2</sup>=0.91), 1.02 in central (R<sup>2</sup>=0.88), 0.99 in south (R<sup>2</sup>=0.88), and 1.13 in whole hilly area of central Sichuan Basin (R<sup>2</sup>=0.91), respectively. The trend analysis based on monthly ET<inf>0</inf> showed that the trend of ET<inf>0</inf> based on modified HS model was the same as that from PM model, which performed as the downwards Quadratic parabola in one year but increasing slightly in years from 2003 to 2013. The relative error of ET<inf>0</inf> obtained from the modified and original HS model was above zero, and the former was smaller. Therefore, the modified Hargreaves-Samani model based on Bayesian Theory is more adaptive and accurate, and can be used as a simple method for the calculation of ET<inf>0</inf> in hilly area of central Sichuan Basin. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:26
Main heading:Computation theory
Controlled terms:Decision theory - Estimation - Evapotranspiration - Irrigation - Meteorology - Models
Uncontrolled terms:Bayesian theory - Central Sichuan Basin - Food and agriculture organizations - Hargreaves - Penman Monteith - Reference crop evapotranspirations - Reference evapotranspiration - Temperature coefficient
Classification code:443 Meteorology - 444.1 Surface Water - 821.3 Agricultural Methods - 902.1 Engineering Graphics - 921 Mathematics
DOI:10.11975/j.issn.1002-6819.2015.11.019
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 22>
Accession number:20152701006238
Title:Effects of drought stresses and times on compensation effect after re-watering in soybean
Authors:Wang, Libin (1); Zu, Wei (1); Dong, Shoukun (1); Liu, Lijun (1); Xu, Yahui (1); Li, Xuening (1)
Author affiliation:(1) College of Agriculture, Northeast Agricultural University, Harbin, China
Corresponding author:Dong, Shoukun
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:150-156
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:As a kind of abiotic stress, drought stress is a common phenomena existing in the plant growth environment. Although drought could cause negative effects such as plant damaged, it also have a positive compensation effect or super compensation effect on physiological and biochemical metabolism during plant growth and development in a short re-watering period after certain drought stress condition, which could make up the loss or damage. Compensation effect, as an important self-regulation mechanism during plant defense responses or resistant to damage, was widely existed in plants and became an important physiological basis for available water regulation and water-saving high-efficiency agriculture realization. At present, drought is the universal phenomenon in spring, of which it in summer and spring-summer has been common and occurred more frequently and the degree was aggravated in recent years in our country. Therefore, in order to explore the metabolic of growth compensation effect and metabolic compensation effect on soybean drought stress and re-watering and establish the best water-saving irrigation mode, we analyzed the effect of drought stress and re-watering on growth, osmotic regulation, endogenous hormone regulation and anti-oxidation system during different stress periods, stress levels and processing times by weighing control the water content, with Sui Nong 14 as experimental material. The results showed that, plant height and leaf area of soybean were inhibited by drought stress, and the decreasing range was 12.50%-39.74%, 21.71%-52.87% and 16.93%-36.27%, 27.99%-47.80% in seeding stage and flowering stage at 0 d re-watering, respectively. The content of praline, soluble sugar and MDA were increased by 46.97%-131.57%, 99.56%-139.37%, 6.64%-22.82% and 31.68%-136.30%, 32.63%-184.51%, 15.82%-100.75% in seeding stage and flowering stage at 0 d re-watering, respectively. The activity of SOD was increased with a decreasing tendency under 10d severe drought stress. The content of ABA was increased, with GA and ZR decreasing, IAA decreased in seedling stage and increased in flowering period. After re-watering, the daily increasing of plant height and leaf area showed a rapid growth in short-term with the over growth compensation effect, metabolic indices in moderate drought stress and 5 d drought stress treatments returned to control levels with a equal or approximately equal metabolic compensation effect; of which these in serious drought stress and 10 d drought stress treatments were showed an approximately equal or partial metabolic compensation effect. This implied that the occurrence of compensation effect under drought stress after re-watering was conditional. The severe drought stress or long time drought stress could decreased the compensation effect and damaged the plant at last, while the appropriate drought treatments in seedling period could improve drought adaptability and compensation effect under once again the drought stress in flowering. Therefore, a moderate drought resistance exercise should be carried out in seedling stage in order to improve the adaptability with drought environment in the late growing, but not suitable for severe drought stress especially for long time. A best water-saving irrigation mode should be established by reasonable utilization of plant drought compensation effect mechanism so that it could be provide a theoretical for the analysis of compensation effect mechanism and cultivation techniques of drought resistance and high yield on soybean. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:27
Main heading:Drought
Controlled terms:Ablation - Cultivation - Growth (materials) - Irrigation - Metabolism - Physiological models - Physiology - Plants (botany) - Seed - Stresses - Water conservation - Water resources
Uncontrolled terms:Compensation effects - Drought stress conditions - Experimental materials - Physiological and biochemical metabolisms - Re-watering - Self-regulation mechanisms - Soybean - Water-saving irrigation
Classification code:421 Strength of Building Materials; Mechanical Properties - 444 Water Resources - 461.1 Biomedical Engineering - 461.9 Biology - 641.2 Heat Transfer - 821.3 Agricultural Methods - 821.4 Agricultural Products - 951 Materials Science
DOI:10.11975/j.issn.1002-6819.2015.11.022
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 23>
Accession number:20152701006244
Title:Early recognition of winter wheat area based on GF-1 satellite
Authors:Wang, Limin (1); Liu, Jia (1); Yang, Fugang (1); Fu, Changhong (1); Teng, Fei (1); Gao, Jianmeng (1)
Author affiliation:(1) Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:194-201
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:GF-1 Satellite is the first one of the high resolution satellite series in China. Since its launch on April 26, 2013, GF-1 Satellite has provided a large amount of satellite data with high spatial resolutions of 2, 8 and 16 m, and it has become one of the major data sources for agricultural remote sensing monitoring in China. By taking WFV (wide field view) Sensor carried on GF-1 Satellite with the spatial resolution of 16 m as its major data source, using the data of 4 time phases, i.e. October 2, October 17, November 07 and December 05, 2013, and taking the objects after multi-resolution segmentation as its basic classification units, the paper extracts the winter wheat area by employing hierarchical decision tree classification method, and verifies the accuracy of the classification result by using the ground sample data. The result shows that, the total winter wheat area in Shunyi District, Beijing City is 7095 hm<sup>2</sup>, with the overall classification accuracy of 96.7% and mapping accuracy of 90.0%. Accuracy of other unclassified types is 97.3%, with the Kappa coefficient of 0.8. The sowing period of winter wheat in the study area is classified into 4 sowing types: Early sowing (October 1st-5th), mid-term sowing (October 6th-10th), mid-late sowing (October 11th-15th) and late sowing (October 16th-20th). It is found that the NDVI (normalized difference vegetation index) values of winter wheat in above 4 sowing periods show a changing pattern of high-low-secondary high-high, which is closely associated with the development features of winter wheat. The higher the NDVI value on October 2nd, the later the sowing period of winter wheat will be, and the higher the NDVI value on December 5th, the earlier the sowing period will be. The change of NDVI value of late sowing winter wheat is the most significant. Under the support of ground training samples, the threshold range of NDVI is classified, and the 4 winter wheat's sowing periods, i.e. early, mid-term, mid-late and late sowing are corresponding to different NDVI levels. With the NDVI values of different levels not overlapping, the paper calculates 32 parameters of 4 types, such as the reflectivity in Waveband 1-4, the sum total of the reflectivity of Waveband 1-4, the ratio between Waveband 4 and 3 and the ratio between Waveband 3 and 2.The threshold values of the 32 parameters are sequentially screened by employing decision tree classification method. Decision tree process includes the following steps: 1) To set up step length of 32 parameters; 2) To randomly select 10% of the step length combination; 3) To calculate the decision results of each combination; 4) To verify the accuracy of the results by relying on 10 training samples; 5) To select the combination with the highest accuracy as the threshold value of a decision tree node. Multi-temporal remote sensing data provided by GF-1/WFV can reliably reflect the changing law of winter wheat development. By data layering, the ground object types which are easy to be confused with winter wheat, such as grass lawn and peach tree, can be effectively eliminated, and the data can be taken as the foundation for accurate extraction of winter wheat area. Thus, GF-1/WFV has great development and application potential in remote sensing monitoring operations for crop area. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:39
Main heading:Crops
Controlled terms:Data mining - Decision trees - Reflection - Remote sensing - Sampling - Satellites - Trees (mathematics)
Uncontrolled terms:Decision tree classification - Development and applications - GF-1 - Hierarchical decision trees - Multi-temporal remote sensing - Normalized difference vegetation index - Recognition - Winter wheat areas
Classification code:655.2 Satellites - 711 Electromagnetic Waves - 723.3 Database Systems - 731.1 Control Systems - 801 Chemistry - 821.4 Agricultural Products - 921.4 Combinatorial Mathematics, Includes Graph Theory, Set Theory
DOI:10.11975/j.issn.1002-6819.2015.11.028
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 24>
Accession number:20152701006223
Title:CFD simulation and validation of trajectory and deposition behavior of droplets around target affected by air flow field in greenhouse
Authors:Wang, Jingxu (1); Qi, Lijun (1); Xia, Qianjin (2)
Author affiliation:(1) Department of Engineering, China Agricultural University, Beijing, China; (2) Department of Engineering Mechanics, Tsinghua University, Beijing, China
Corresponding author:Qi, Lijun
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:46-53
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The trajectory and adhesion behavior of droplets in air-assisted pesticide spraying in greenhouse are closely related with several factors: the velocity field and pressure field of the airflow, the droplets properties (such as droplet size, initial velocity), the spraying angle, as well as the target parameters (such as shape, size and position). This study explored the conditions that influenced the droplets carried by airflow, with a keen emphasis on whether it could touch, instead of going around, and stay on the target. A CFD (computational fluid dynamics) model was introduced for droplet trajectory simulation in an airflow field, in which droplets were traced by discrete phase particle tracking method. A computation region of 1600, 720 and 1000 mm respectively in streamwise, spanwise and normalwise was established. A target with the dimension of 120 mm×120 mm×30 mm was placed 400 mm above ground and 840 mm away from the left boundary of the computational domain. To simplify computational complexity, only half of the computational region (1600 mm×360 mm×1000 mm) was computed since the whole region was symmetric on both sides of the sprayer in streamwise. The grid number of the actual computation domain was about 0.36 million. A local mesh encryption method was applied around the target in order to increase the resolution of the simulation. The particle diameters involved in this simulation were 10, 30, 40, 50, 60, 70, 80 and 100 μm; and the injection angles were adjusted to 90°, 75°, 60°, 45°, 30° and 15° respectively. A discrete phase boundary condition was set which trapped the droplets on the ground (wall) or the target surfaces. The rest of boundaries for discrete phase were set to boundary condition of droplet escaping. The influences of droplet velocity, droplet size and injection angle on deposition rate were evaluated by the CFD simulation and the experiments proved that: the condition of a droplet touching and adhering on target was that the maximum moving time of droplets in x and y direction should be simultaneously longer than the maximum moving time of droplets in z direction in the region around the target. There was a region below the target where droplets could not reach while spraying, and the length of the region was related to spraying angle. The adhesion behavior of droplets was affected by air velocity and droplet size. When the droplet size was 50 μm and spraying angle was 60°, the larger the spraying velocity, the lower the deposition rate. The comparison of the deposition rates from simulations and experiments proves that the experiment data agree well with the data from simulation, so the simulation can be taken as reliable and valid measure in droplet deposition evaluation under greenhouse condition. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:31
Main heading:Drops
Controlled terms:Adhesion - Air - Boundary conditions - Computational fluid dynamics - Deposition - Deposition rates - Drop formation - Flow fields - Fluid dynamics - Greenhouses - Trajectories - Velocity
Uncontrolled terms:CFD (computational fluid dynamics) - Computation domains - Computational domains - Deposition behavior - Deposition distribution - Droplet trajectories - Greenhouse conditions - Simulation
Classification code:402.1 Industrial and Agricultural Buildings - 404.1 Military Engineering - 617 Turbines and Steam Turbines - 631.1 Fluid Flow, General - 804 Chemical Products Generally - 813.1 Coating Techniques - 921 Mathematics - 931.1 Mechanics - 931.2 Physical Properties of Gases, Liquids and Solids
DOI:10.11975/j.issn.1002-6819.2015.11.007
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 25>
Accession number:20152701006228
Title:Design of axial-flow impeller guide cone and simulation on hydraulic performance of its passage
Authors:Yang, Minguan (1); Meng, Yu (1); Li, Zhong (2); Gao, Bo (1); Ni, Dan (1)
Author affiliation:(1) Department of Energy and Power Engineering, Jiangsu University, Zhenjiang, China; (2) Eindhoven University of Technology, Eindhoven, Netherlands
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:81-88
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Axial flow pumps have advantages of large capacity and low head and the impeller is an important component of axial-flow pump. Guide cone is usually installed on the top of impeller and its appropriate design can enhance flow quality of pump inlet, lower turbulivity, make velocity steady, and so on. To meet with engineering demands, find feasible design and investigate the internal flow characteristics of guide cone, we designed different types of guide cones installed on the impeller. Based on three dimensional incompressible Navier-Stokes equation and k-Ε turbulent model, SIMPLEC algorithm was applied to solve a discretization governing equation, five different types of guide cones were designed with contraction curves such as Witozinsky, Bicubic, Fifth degree polynomial curves. The CFD method was used to simulate 3D flow field of guide cone. In order to verify the feasibility of simulation models, the guide cones were installed on the impeller and the simulated head and efficiency values were obtained using simulation method same as the flow field simulation of guide cone. Meanwhile, a laboratory test was performed on a DN200 test bench to measure the pumping head, discharge, and other parameters for calculation of head and efficiency. Results showed that the simulated and measured head and efficiency had relative error less than 4%, indicating the feasibility of the simulation method for flow field simulation of guide cones. Simulation on flow velocity of guide cones suggested three flow processes: 1) flow velocity is even in inlet passage and slightly increased; 2) the flow velocity starts to increase and change its direction in contraction passage of guide cone flow field; and 3) the flow field contraction becomes slow in the outlet passage of guide cone. Hydraulic loss of different guide cones varied. The head loss of circular cone was lower than the others. In the sharp contraction cross section of guide cone passage, the uniformity of axial velocity distribution was low, but the velocity weighted average drift angle and radial velocity gradient was high. The rectification capability was better when the contraction at outlet section of guide cone flow field was slow and gentle. Taking into account of uniformity of axial velocity, velocity weighted average drift angle, and the others, the guide cone based on Witozinsky curve had the best rectification capacity and better flow field uniformity. When the length of guide cone was 0.25-0.8 times as impeller diameter, increasing cone length could decrease the hydraulic loss and velocity weighted average drift angle, and improve flow field quality of cone. The results above in combination with practical application, we suggested that the optimal length of the guide cone was 0.5-0.6 times as impeller diameter. This study is helpful to design hydraulic models of high-efficient axial-flow pumps. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:18
Main heading:Computational fluid dynamics
Controlled terms:Axial flow - Cyclone separators - Design - Efficiency - Flow fields - Flow velocity - Hydraulic models - Impellers - Navier Stokes equations - Polynomial approximation - Pumps - Statistical methods - Three dimensional computer graphics - Velocity - Velocity distribution
Uncontrolled terms:Axial-velocity distribution - Fifth degree polynomials - Flow field simulation - Guide cone passages - Hydraulic performance - Incompressible Navier Stokes equations - Internal flow characteristics - Simulation
Classification code:408 Structural Design - 601.2 Machine Components - 618.2 Pumps - 631 Fluid Flow - 631.1 Fluid Flow, General - 632.1 Hydraulics - 723.5 Computer Applications - 802.1 Chemical Plants and Equipment - 913.1 Production Engineering - 921.6 Numerical Methods - 922.2 Mathematical Statistics - 931.1 Mechanics
DOI:10.11975/j.issn.1002-6819.2015.11.012
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 26>
Accession number:20152701006254
Title:Influence of biomass component interaction on product characteristics during hydrothermal treatment
Authors:Gao, Ying (1); Wu, Ke (1); Yuan, Qiaoxia (1); Chen, Hanping (2); Wang, Xianhua (2); Yang, Haiping (2)
Author affiliation:(1) Engineering Technology Academy, Huazhong Agriculture University, Wuhan, China; (2) State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan, China
Corresponding author:Yuan, Qiaoxia
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:262-268
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The interaction among three biomass components (hemicellulose, cellulose, and lignin) in autoclave was studied in detail on the basis of the extreme vertices of a constrained region. Such interaction was found to have a distinct effect on product yield and characteristics. The yield of heavy oil was highest when the mixing proportion of the three components was 0.2:0.4:0.4 at 40.10 wt.%, and was lowest when the mixing proportion was 0.65:0.25:0.1 at 28.20 wt.%. When the mixing proportions were 0.3:0.2:0.5 and 0.2:0.3:0.5, the yield of the solid residue was as high as 14.00 wt.%. In the mixing experiment of the three components, when the cellulose proportion was high, the heavy oil and solid residue yields were low, whereas those of light oil and gas were high, which indicated that cellulose was first hydrolyzed into sugar products through hydrothermal conversion. The comparison results of the mixing and single-component experiments showed that when cellulose, hemicellulose, and lignin were mixed in different proportions to form biomass, the yield of heavy oil increased, whereas that of solid residue decreased. The yields of light oil and gas were between those of cellulose and lignin. Results of gaseous products show that products from cellulose hydrolysis could promote hemicellulose hydrolysis and generate large amounts of CO<inf>2</inf>. The interaction between cellulose and hemicellulose under different mixing proportions increased the CO<inf>2</inf> yield compared with that of the single component. Relatively, the influence on CO, CH<inf>4</inf>, and CnHm was weak. The lignin content, as well as the low cellulose and hemicellulose contents, inhibited the acid and ketones in light oil. High lignin content could promote the hydrolysis of cellulose and hemicellulose to produce acids, and the interaction among the three components inhibited the generation of acids. In addition, the lignin proportion also affected the relative acids. When the lignin proportion was greater than 0.4, the inhibition effect of the interaction on the acids weakened. In addition, the interaction among cellulose, hemicellulose, and lignin inhibited the production of acid compounds in heavy oil and promoted phenolics. The acid in the heavy oil of lignin was mainly homovanillic acid about 9.07%. When lignin, hemicellulose, and cellulose were mixed with certain proportions, the acid in the heavy oil reduced. After mixing, the homovanillic acid was highest at only 2.4%, which indicated that the interaction among the three components inhibited the generation of acids in heavy oil, thus, improving the heavy oil quality. The interaction among the three components promoted a series of hydrolysis product reactions, such as polymerization and condensation, to generate char, thus resulting in a high degree of aromatization. The hemicellulose in the mixed proportion slightly influenced the infrared absorption peak of the char. The absorption peaks under the 1-11 mixing proportions were stronger than that of the single hemicellulose. Hemicellulose was hydrolyzed completely at 200 to 230 to generate gas and liquid products with CO<inf>2</inf> and small molecular oxygen compounds as the primary outcomes, namely, sugars, acids, aldehydes, and phenols. These compounds had certain promoting functions in the hydrolysis of cellulose and lignin, and caused new condensation and polymerization on hydrolysis products to generate a solid residue. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:29
Main heading:Heavy oil production
Controlled terms:Biomass - Cellulose - Condensation - Crude oil - Hydrolysis - Ketones - Light absorption - Lignin - Mixing - Molecular oxygen - Oil wells - Polymerization
Uncontrolled terms:Extreme vertices - Hemicelluloses - Hydrothermal treatments - Interaction - Three component
Classification code:512.1.1 Oil Fields - 512.1.2 Petroleum Deposits : Development Operations - 523 Liquid Fuels - 525.1 Energy Resources and Renewable Energy Issues - 741.1 Light/Optics - 802.2 Chemical Reactions - 802.3 Chemical Operations - 804.1 Organic Compounds - 804.2 Inorganic Compounds - 815.1.1 Organic Polymers - 815.2 Polymerization
DOI:10.11975/j.issn.1002-6819.2015.11.038
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 27>
Accession number:20152701006256
Title:Suitability evaluation method and application for land reclamation to grassland in Xinjiang coal mines
Authors:Zhang, Zizhao (1); Guo, Ruiqing (1); Zhou, Tiansheng (2); Zhu, Jianhua (3); Xian, Quan (4)
Author affiliation:(1) School of Geological and Mining Engineering, Xinjiang University, Urumqi, China; (2) Yili Institute of Geo-Environment Monitoring, Yining, China; (3) Office of Market Project Management, Xinjiang Institute of Geo-Environment Monitoring, Urumqi, China; (4) No. 1 Hydrogeology & Engineering Geology Exploration Team of Xinjiang Geology and Mineral Bureau, Urumqi, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:278-286
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Nowadays, a large number of land reclamation projects have been carried out or in the process of construction in coal mining areas of Xinjiang, and it is necessary to build up classification index and discriminant model to evaluate the suitability of land reclamation, for reducing the destruction of land and sustaining the development of coal mine. This article focused on the research of the theory of suitability evaluation of land reclamation and established a discriminant model that was used for the evaluation of coal mining areas in Xinjiang. The main type of destructed land in Xinjiang was grassland and bare land, so the land reclamation suitability evaluation was aimed at grassland. The results of land reclamation evaluation were divided into the most suitable, moderately suitable, barely suitable and unsuitable. One of the core issues of land reclamation is to construct evaluation index system. Taking 15 coal mines in Xinjiang as the research subjects, based on Bayes discrimination analysis, the factors of suitability evaluation of land reclamation of mines were analyzed; combined with the characteristics of land destruction and ecological geography of coal mines in Xinjiang, 7 factors such as the slope of land reclamation unit after land destruction, the depth of land destruction or the deposit amount of land occupancy, the guaranteed rate of soil for land reclamation, the clay content in soil, the thickness of topsoil, river runoff for irrigation of land reclamation unit and the content of organic matter in soil were selected as the evaluation factors. Each evaluation factor quantization value was taken from the measured value and the related report data. The 76 land reclamation units of 15 coal mines were used as the study samples. The Q clustering analysis method was used to classify 76 samples. The clustering analysis used the method of average connection to define the distance of categories for merging samples, and the distance was measured by the squared Euclidean distance. The results showed that the best plan was the 4 categories. Compared with the code, the classification results of this method were more realistic and accurate. By taking the 76 land reclamation units of 15 coal mines in Xinjiang as the training samples, the Bayes discriminant model for suitability evaluation of land reclamation of coal mining areas in Xinjiang was established. This model was composed of 4 discriminant functions. Every sample was tested by using the resubstitution method, and the correct rate was equal to 98.7%. The discriminant model was applied to 2 coal mines in Xinjiang. The results showed that the classification results were entirely consistent with the neural network method and the combination of factor and clustering analysis. The classification results complied with the classification result range of the code and were more accurate and realistic. The results of the modelling test and calculation have proved that the structure of Bayes discriminant is stable, and the discriminant effect is ideal. This model has strong analysis ability for suitability evaluation of land reclamation in coal mining areas of Xinjiang. The biggest difference between the results of evaluation model and the code was that results of evaluation model are more specific and detailed than that of code, especially in barely suitable category and unsuitable category. The classification results of this model are more accurate. This evaluation model can be widely used in suitability evaluation for land reclamation of coal mining areas in Xinjiang. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:35
Main heading:Land reclamation
Controlled terms:Classifiers - Clay deposits - Cluster analysis - Coal - Coal deposits - Coal mines - Coal reclamation - Coal research - Codes (symbols) - Factor analysis - Land use - Reclamation - Soils
Uncontrolled terms:Classification index - Classification results - Discriminant functions - Evaluation index system - Grassland - Neural network method - Squared euclidean distance - Suitability evaluation
Classification code:442.2 Land Reclamation - 452.4 Industrial Wastes Treatment and Disposal - 482 Mineralogy - 483.1 Soils and Soil Mechanics - 503 Mines and Mining, Coal - 503.1 Coal Mines - 505.1 Nonmetallic Mines - 524 Solid Fuels - 723 Computer Software, Data Handling and Applications - 723.2 Data Processing and Image Processing - 802.1 Chemical Plants and Equipment - 922 Statistical Methods - 922.2 Mathematical Statistics
DOI:10.11975/j.issn.1002-6819.2015.11.040
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 28>
Accession number:20152701006241
Title:Simulated experiment for preventing slope soil erosion using corn stalk juice as soil amendment
Authors:Wei, Xia (1); Li, Xungui (1); Huang, Chihua (2)
Author affiliation:(1) College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, China; (2) Agronomy Dep., Purdue Univ. and USDA-ARS National Soil Erosion Research Lab., 275 S Russell St, West Lafayette; Indiana, United States
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:173-178
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Although polyacrylamide and other manufactured soil amendments have been effective in runoff and sediment reduction, there is a need to seek natural products that may provide the same soil conservation benefits. In the process of developing green biomass utilization, such as fiber extraction, the plant juice becomes a natural byproduct because only water is used in the extraction. In this research, corn stalk juice was tested for its effects on runoff generation intensity and sediment yield intensity. The experimental design involved four simulated rainfall intensities (25, 50, 75, and 100 mm/h), four diluted corn stalk juice concentrations (10%, 25%, 50%, and 75%), and two diluted corn stalk juice amounts (400 and 800 g) on four 0.5-m-long, 0.2-m-wide, and 0.1-m-deep soil boxes set at 5% slope. Experiments were conducted at the USDA-ARS National Soil Erosion Research Lab. Surface soil (0-10 cm) of a Crosby-Miami complex alfisol with 20% clay, 66% silt and 14% sand was from the Purdue Animal Science Research and Education Center in West Lafayette, Indiana. The test soil was air-dried, crushed and then passed through an 8-mm sieve. The corn stalk juice used in this study was extracted from field corn plants grown at Purdue Agronomy Farm at West Lafayette, Indiana. A 100-min continuous rainstorm was applied. The storm consisted of four intensity sequences: 50 mm/h for 60 min, 25 mm/h for 20 min, 75 mm/h for 10 min and 100 mm/h for 10 min. Runoff samples were collected in 1-liter HDPE bottles every 5 min during the two lower intensity rains and every 3 min during the two higher intensity rains. Time to fill the runoff bottle was recorded. After each run, the sample bottles were weighed immediately to obtain the runoff rate. Approximately 5 mL of saturated alum solution was added to the sample bottles to flocculate the suspended sediment. After settling overnight, the excess water was poured off the bottles. The bottles were placed in the oven set at 105 for at least 24 h or until the sediments were dried. Dry weights were then taken to calculate the sediment delivery rate and concentration. The results showed that all kinds of diluted corn stalk juice applications and concentrations reduced runoff generation intensity and sediment yield intensity. Sediment reduction benefit was greater than the corresponding runoff reduction benefit under the same diluted corn stalk juice application and concentration. When diluted corn stalk juice application was 400 g, runoff reduction ratio was 31.243%, 31.685%, 34.595%, 39.475% and sediment reduction ratio was 23.167%, 41.993%, 37.918%, 64.606% with diluted corn stalk juice concentration increasing from 10% to 25%, 50% and 75%, respectively. When diluted corn stalk juice application was 800 g, runoff reduction ratio was 37.583%, 56.433%, 63.170%, 76.360% and sediment reduction ratio was 48.214%, 77.219%, 88.572%, 95.539% with diluted corn stalk juice concentration increasing from 10% to 25%, 50% and 75%, respectively. The relationships of runoff generation intensity and diluted corn stalk juice concentration, sediment yield intensity and diluted corn stalk juice concentration were both established as decreasing exponential function when diluted corn stalk juice application and rainfall intensity were both same. The relationship between sediment yield intensity and rainfall intensity was established as increasing power function when diluted corn stalk juice application and concentration were both same. However, the relationship between runoff generation intensity and rainfall intensity was relatively complex. When diluted corn stalk juice application amount was 400 g, the relationship between runoff generation intensity and rainfall intensity was established as a significant increasing linear function. When diluted corn stalk juice application amount was 800 g, the relationship between runoff generation intensity and rainfall intensity was established as a significant increasing exponential function. This research can provide a new idea for prevention and control of soil erosion by water, and provide a new method for the prevention and control of water erosion desertification. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:16
Main heading:Soil conservation
Controlled terms:Bottles - Erosion - Exponential functions - Extraction - Rain - Runoff - Sediments - Soil conditioners - Soil structure interactions - Soils - Storms - Suspended sediments
Uncontrolled terms:Conservation benefits - Corn stalk - Juice concentrations - Prevention and controls - Runoff and sediments - Simulated experiments - Simulated rainfall - Soil and water loss
Classification code:443.3 Precipitation - 444.1 Surface Water - 483 Soil Mechanics and Foundations - 694.2 Packaging Materials - 802.3 Chemical Operations - 921 Mathematics
DOI:10.11975/j.issn.1002-6819.2015.11.025
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 29>
Accession number:20152701006221
Title:Design of automatic and uniform feeding system carried by workboat and effect test for raising river crab
Authors:Sun, Yueping (1); Zhao, Dean (1); Hong, Jianqing (1); Zhang, Jun (1); Li, Fazhong (1)
Author affiliation:(1) School of Electrical and Information Engineering, Jiangsu University, Zhenjiang, China; (2) School Key Laboratory of Facility Agriculture Measurement and Control Technology and Equipment of Machinery Industry, Jiangsu University, Zhenjiang, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:31-39
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In order to solve the feeding problem in river crab aquaculture such as high labor intensity, low automation and non-uniform feed distribution, an automatic air propeller driven feeding system carried by a workboat and uniform feeding method was proposed. The system is mainly composed of a workboat driven by air propellers, automatic feeding device, ARM (advanced RISC machine) main controller, GPRS (general packet radio service) communication module and GPS (global positioning system) navigation device. A air propeller driven device was designed to solve the effect of waterweeds intertwine with underwater propellers of common workboat on sailing, and an automatic feeding device equipped with the flow velocity controllable bait feeder, distance adjustable thrower and quantity of feed in the bin measurable device was designed to solve the problem of non-uniform distribution of the feed. The ARM S3C2440 was used for the control system which could perform automatic uniform feeding by receiving task information through the GPRS communication module M590, modeling for the thrower of the automatic feeding device, motion of the feed particle and cumulative distribution of feed on the water, creating a target function for cumulative distribution density, using genetic algorithm (GA) to solve the optimal operation parameters such as flow velocity of the feeder, speed of the rotary table, feed sector angle, speed of the workboat and distance between adjacent feeding travel of trajectory planning which optimal value of distance between adjacent feeding travel was 8.21 m, feed sector angle was 80°, the workboat speed above and below the feeding travel were both 0.43 m/s, flow velocity of the feeder was 32.01 g/s, speed of the rotary table was 1480 r/min when the expected value of distribution density was 9 g/m<sup>2</sup>, and implementing trajectory tracking by GPS navigation device BD982. We conducted simulation of oblique throwing movement, feed average cumulative distribution density and distribution density variance, feeding contrast test between feeding device and artificial on the ground and feeding test on pond respectively. The results showed that the automatic feeding system can obtain good uniform feeding effect by working with the optimal operation parameters. The feed distribution uniformity of the automatic feeding system carried by workboat can be increased by three times than that with the artificial feeding, compared with the feed distribution density set value, the feed average distribution density relative error was 5.11%. In order to adapt the river crabs nocturnal habits, the automatic feeding can be performed in the night, one automatic feeding system carried by workboat could fine management about 6.67 hm<sup>2</sup> crab pond which was equivalent to feeding with five rural labor force so that it would save manpower and increase efficient utilization of the feed. The automatic feeding system carried by workboat could make the feed utilization rate improved by more than 15%, resulting feed saving by more than 15% and crab output per unit area increased by more than 20%. At the same time, the automatic feeding system carried by workboat could perform timing; quantitative and uniform feeding which ensured that river crabs grow with equal size, as such improved the production and aquaculture area use efficiency. This research provides technology reference for further study of automatic uniform feeding on the whole pond in river crab aquaculture and other aquaculture needing for feeding along the pond or on the whole pond. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:31
Main heading:Feeding
Controlled terms:Air - Air navigation - Aquaculture - Automation - Cultivation - Emergency traffic control - Equipment - Flow velocity - Genetic algorithms - Global positioning system - Lakes - Materials handling equipment - Models - Navigation - Navigation systems - Propellers - Radio communication - Radio navigation - Rivers - Shellfish - Target tracking - Tracking (position)
Uncontrolled terms:Advanced RISC machines - Automatic feeding systems - Cumulative distribution - Distribution uniformity - Feeding system - GPRS (general packet radio service) - Gps (global positioning system) - Non-uniform distribution
Classification code:407 Maritime and Port Structures; Rivers and Other Waterways - 407.2 Waterways - 431.5 Air Navigation and Traffic Control - 461.9 Biology - 631 Fluid Flow - 671.2 Ship Equipment - 691.1 Materials Handling Equipment - 691.2 Materials Handling Methods - 716.2 Radar Systems and Equipment - 716.3 Radio Systems and Equipment - 723 Computer Software, Data Handling and Applications - 731 Automatic Control Principles and Applications - 731.2 Control System Applications - 732 Control Devices - 804 Chemical Products Generally - 821.3 Agricultural Methods - 901 Engineering Profession - 902.1 Engineering Graphics - 921 Mathematics
DOI:10.11975/j.issn.1002-6819.2015.11.005
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 30>
Accession number:20152701006227
Title:Analysis on transient characteristics of tip leakage vortex in axial flow pump using large eddy simulation
Authors:Zhang, Desheng (1); Shi, Lei (1); Chen, Jian (1); Geng, Linlin (1); Wu, Suqing (1)
Author affiliation:(1) Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:74-80
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Numerical analysis of the unsteady flow in an axial flow pump was conducted to understand deeply the characteristics of turbulence in the tip region via LES (large eddy simulation) in ANSYS CFX. Such an understanding was critical to predict and eventually control cavitation and noise as well as vibration in liquid handling systems such as pumps and propellers, and improve their performance. Compared with the conventional numerical methods, LES provided the most promising and feasible alternative to compute the unsteady velocity and pressure fields. In this paper, LES method with large mesh-size requirement was used for studying the transient characteristics of the tip leakage flow and leakage vortex. Some significant conclusions were obtained by the simulation. The responsibility of different flow rate for variation of average head and efficiency calculated by LES had little discrepancy with the experimental values in the low-head axial flow pump model, especially at flow rate condition. A combination of the time-domain and frequency-domain graphs of pressure difference coefficient and leakage velocity coefficient at different chord sections were presented in this paper. It was found that the mutual promotion and restriction relationship between pressure difference and leakage velocity in the tip region was obvious, which led to the unsteady characteristics of the tip leakage flow. The tip leakage dynamics mentioned above could help others understand the underlying mechanisms of low-pressure fluctuations and tip-leakage vortex oscillations. Then, different types of tip vortexes were seen according to three-dimensional structure of leakage vortex, including the corner vortex generated by the flow separation near the pressure side, separated vortex shed from the tip into the shear layer, tip leakage vortex A formed due to the interaction between the leakage flow and the mainstream, as well as the swirl in the tip clearance. The main leakage vortex strip absorbed vortex filaments shed from the tip in the shear layer, which could provide the power for the generation of the main tip leakage vortex. The main leakage vortex was separated from the shear layer, meanwhile there was the phenomenon of "pinch off", and the main leakage vortex strip was shortened gradually because of the dissipation of its movement and the integration of the mainstream. Due to the faster transient change of the small-scale vortex in the gap compared with the tip leakage vortex, the re-generation cycle of vortex filaments in shear layer was shortened, and then the secondary leakage vortex strip was created above the main vortex strip. From the in-plain leakage vortex structure with mean streamlines and vorticity contours, it could be seen that the separation vortex in shear layer constantly was separated and then rolled up by the leakage vortex with the increasing of chord coefficient, which could drive the main leakage vortex to move forward, however, the vorticity of the main leakage vortex decreased during the moving process towards the pressure surface of the neighboring blade and the counter-rotating induced vortexes were generated constantly, at the same time, the scope of the main leakage vortex expanded a lot, and a large fraction of the wake downstream of the leakage vortex were produced, which could affect the flow field in the passage and enhance the instability of the flow field. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:20
Main heading:Vortex flow
Controlled terms:Axial flow - Flow fields - Flow rate - Flow separation - Frequency domain analysis - Large eddy simulation - Leakage (fluid) - Numerical methods - Pumps - Shear flow - Time domain analysis - Turbulent flow - Vorticity
Uncontrolled terms:Axial-flow pump models - Feasible alternatives - Leakage vortex - Pressure difference coefficient - Three-dimensional structure - Tip - Transient characteristic - Unsteady characteristics
Classification code:452.3 Industrial Wastes - 617 Turbines and Steam Turbines - 618.2 Pumps - 631 Fluid Flow - 631.1 Fluid Flow, General - 921 Mathematics
DOI:10.11975/j.issn.1002-6819.2015.11.011
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 31>
Accession number:20152701006232
Title:Distributed modeling of soil water-salt dynamics and crop yields based on HYDRUS-EPIC model in Hetao Irrigation District
Authors:Hao, Yuanyuan (1); Xu, Xu (1); Ren, Dongyang (1); Huang, Quanzhong (1); Huang, Guanhua (1)
Author affiliation:(1) Center for Agricultural Water Research in China, China Agricultural University, Beijing, China; (2) Chinese-Israeli International Center for Research and Training in Agriculture, Beijing, China
Corresponding author:Huang, Guanhua
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:110-116
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Soil moisture and salinity are two key factors for crop production in arid irrigation districts. It is critical to modify soil water-salt dynamics and crop growth on a regional scale for the sustainable agriculture. In this paper, a distributed agro-hydrological model that well considers the spatial variability of soil and hydrological factors was developed to simulate soil water movement, solute transport and crop growth process on the regional scale. Jiefangzha Irrigation System (JIS) of the Hetao Irrigation District was selected as the study area. The JIS was divided into 201 homogeneous simulation units based on the combinations of weather-soil-crop-irrigation. In this way, the one-dimensional agro-hydrological model-HYDRUS-EPIC (HYDRUS-1D coupled with EPIC crop growth module), was used and expanded to the regional scale. Field experiments were conducted in 2012 and 2013. The dataset of soil moisture, soil solute concentration, leaf area index (LAI) and crop yield were collected at 40 monitoring points, and used for model calibration and validation. Simulated soil moisture and salinity concentration in the root zone showed good agreement with the measured values. During the calibration process, root mean square error (RMSE), mean relative error (MRE) and coefficient of determination (R<sup>2</sup>) for soil moisture were 0.03 cm<sup>3</sup>/cm<sup>3</sup>, 0.3% and 0.67, respectively. For salinity concentration, RMSE, MRE and R<sup>2</sup> were 2.72 g/L, -13.5% and 0.53.LAI and crop yields were fitted well with the observations. MRE values for the estimated and measured LAI and crop yields were 1.0% and 1.1%, and R<sup>2</sup> were both larger than 0.90 for these two items. During the validation process, RMSE, MRE, and R<sup>2</sup> were 0.04 cm<sup>3</sup>/cm<sup>3</sup>, 2.6%, 0.57 for soil moisture, and 2.62 g/L, -4.5%, 0.51 for salinity concentration, respectively. And MRE and R<sup>2</sup> were 9.1%, 0.88 for LAI, and -1.9%, 0.92 for crop yields. These results showed that the distributed agro-hydrological model was able to simulate the soil water flow, salt transport, and crop growth process in JIS with accuracy. The calibrated and validated model was then applied to predict spatial distribution of soil moisture, salinity concentration, crop evaporation and crop yields of the study area in present irrigation water management practices. Effective saturation and salinity concentration in the root zone were chosen to represent soil water and salinity stress on crop growth. Results showed that effective saturation ranged from 0.44 to 0.90 with an average of 0.7 for the JIS. In most areas, soil water could meet crop water consumption needs. In the areas where groundwater depth (GWD) was less than 1.3 m, root water uptake was limited due to waterlogging. The average salinity concentration in the root zone varied from 3.1 g/L in the northwest to 13.5 g/L in the northeast with an average of 6.4 g/L for the whole district. High soil salinity concentration limited crop production seriously. Corresponding to the spatial distribution of salinity concentration in the root zone, crop relative yield (ratio of actual yield and average yield of JIS) ranged from 0.33 to 1.33.The results suggested that for the northeastern part, where GWDs were larger than 2.0 m, more irrigation was needed for leaching salt. It was also better to plant more salt tolerant crops in these areas. In northwestern and southwestern parts, shallow groundwater levels intensified water logging or salinity accumulation problems. The study indicated that it is better to keep the groundwater depth not shallower than 1.3 m for maintaining the crop yields. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:22
Main heading:Crops
Controlled terms:Agriculture - Climate models - Cultivation - Flow of water - Groundwater - Groundwater resources - Hydrology - Industrial plants - Irrigation - Mean square error - Models - Moisture - Moisture determination - Plants (botany) - Soil moisture - Soils - Solute transport - Spatial distribution - Water management - Water supply
Uncontrolled terms:Coefficient of determination - Hetao irrigation districts - HYDRUS-EPIC - Irrigation districts - Irrigation water management - Model calibration and validation - Shallow groundwater levels - Soil solute concentrations
Classification code:402.1 Industrial and Agricultural Buildings - 443 Meteorology - 443.1 Atmospheric Properties - 444 Water Resources - 444.2 Groundwater - 446 Waterworks - 446.1 Water Supply Systems - 461.9 Biology - 471 Marine Science and Oceanography - 483.1 Soils and Soil Mechanics - 631.1.1 Liquid Dynamics - 731.1 Control Systems - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 902.1 Engineering Graphics - 921 Mathematics - 944.2 Moisture Measurements
DOI:10.11975/j.issn.1002-6819.2015.11.016
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 32>
Accession number:20152701006222
Title:3D reverse engineering design on seed tube based on Geomagic Design software
Authors:Liu, Lijing (1); Yang, Hui (3)
Author affiliation:(1) Chinese Academy of Agricultural Mechanization Sciences, Beijing, China; (2) Mordern Agricultural Equipment Co., Ltd., Beijing, China; (3) Shandong Changlin Deutz-Fahr Machinery Co., Ltd., Linshu, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:40-45
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In order to improve the performance of seed tube and solve the problem of bad uniformity of seed spacing caused by unreasonable seed tube structure, this study introduced a method of applying reverse engineering design software Geomagic Design to design seed tube. Reverse engineering is a kind of technology that builds engineering model of products or parts according to prototypes of current products or parts, and then analyzes and improves them. As a new product design method, it plays an important role in absorbing advanced manufacturing technology at home and abroad, shortening product development cycle and reducing production cost. Seed tube is mainly applied in precision planter, which is used to shorten the distance between metering point and dropping point, reduce seed horizontal speed variance between different metering speeds and reduce seed bounce in dropping and falling processes, in order to realize zero-speed dropping seed and make sure of good uniformity of seed spacing. The length of linear part, the angle between linear part and horizontal direction, the curvature of arc part, the central angle of arc part, the cross-sectional area and the smooth degree etc all have significant impact on seed dropping performance. The imported curve-type seed tube was scanned by non-contact laser scanning method of three-coordinate measuring instrument and the three-dimensional (3D) point clouds were obtained. The front and back of the seed tube were scanned respectively in order to get the complete point cloud data; to make the point clouds better matched with the scanned seed tube, unrelated scanned data were deleted through 3D reverse engineering software Geomagic Design, data preprocessing like reducing noise, merging, simplifying, alignment etc. was done, and then the mesh data of seed tube were got. Through the application of 3D reverse engineering software Geomagic Design, based on the mesh data, and by the application features design tools in "design" interface, coordinate system, tube body, semicircle groove, hanger and strip rib and other features were created one by one, and the 3D geometrical model of seed tube was re-built. Error analysis for the re-built 3D geometrical model and the mesh data was done in "measure" interface, and different colors were used to distinguish different errors. If there were large errors, then back to "design" interface and adjust the corresponding features to reduce error and optimize 3D model. The seed tube was trial-produced according to the engineering drawings which were generated from the optimized 3D geometric model. According to the national standard GB/T 20865-2007, the test was done with Fengmei 2BQX-6 corn no-tillage precision seeder, and the performances were compared among the trial seed tube, imported seed tube and without seed tube. Taking the qualified rate of seed number and the no-seed rate in seed channel as the test indices, make a continuous measurement of 100 segments, and the theoretical length of a segment was 250 mm. The results showed that the qualified rates of seed number in seed channel for the trial seed tube, imported seed tube and without seed tube were 95%, 97% and 67% respectively; the no-seed rates in seed channel were 3%, 3% and 33% respectively. It can draw the conclusions that seed tubes can effectively improve seeding quality, and the performance of the trial seed tube is good and equivalent to the imported seed tube. This research can be successfully applied on seed tube design. Applying reverse engineering for designing the seed tube can shorten the design time and reduce the design cost compared with theoretical study and experimental study. The built 3D geometric model provides a certain reference for the improvement and optimization of seed tube. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:26
Main heading:Seed
Controlled terms:Application programs - Cost engineering - Cost reduction - Data reduction - Design - Error analysis - Errors - Geometry - Models - Product design - Product development - Reverse engineering - Software design - Three dimensional computer graphics - Tubes (components)
Uncontrolled terms:Advanced manufacturing technologies - Continuous measurements - Engineering design softwares - Geomagic - Geometrical modeling - Product development cycle - Three dimensional - Threedimensional (3-d)
Classification code:616.1 Heat Exchange Equipment and Components - 723 Computer Software, Data Handling and Applications - 821.4 Agricultural Products - 902.1 Engineering Graphics - 911 Cost and Value Engineering; Industrial Economics - 911.2 Industrial Economics - 913.1 Production Engineering - 921 Mathematics - 921.6 Numerical Methods
DOI:10.11975/j.issn.1002-6819.2015.11.006
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 33>
Accession number:20152701006217
Title:Review on management-induced nitrous oxide emissions from paddy ecosystems
Authors:Xue, Jianfu (1); Pu, Chao (1); Zhang, Ran (1); Zhao, Xin (1); Liu, Shengli (1); Chen, Fu (1); Zhang, Hailin (1)
Author affiliation:(1) Key Laboratory of Farming System, College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
Corresponding author:Zhang, Hailin
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:1-9
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Climate change, as one of the most important environmental issues, has become an increasing global concern to scientists, policy makers, and the public. Paddy soils are a dominant source of N<inf>2</inf>O emissions. Agricultural management practices (e.g., water regime, fertilizers management, tillage) have important impacts on N<inf>2</inf>O emissions due to the changing microenvironment of paddy fields that can affect the processes of soil nitrification and denitrification. This paper summaried current literatures on the influence of these practices on N<inf>2</inf>O production and emission and their corresponding mechanisms in rice fields. At present, the generation and the pathway of N<inf>2</inf>O emission from paddy soils are clarified. Nevertheless, the current information on the action of farming management practices on N<inf>2</inf>O indirect emission is limited. The fertilizer application rate, the various types of fertilizers, and the varying timing and placement of application have a significant effect on the N<inf>2</inf>O emissions of paddy fields due to the different supplementation of nitrate and ammonium substrate in the processes of nitrification and denitrification. Generally, N<inf>2</inf>O emissions increase with increasing nitrogen (N) fertilizer rate. Previous studies showed that applying N fertilizer deeper can decrease N<inf>2</inf>O emissions compared to surface application. Water regime exerts substantial influence on N<inf>2</inf>O emission through the changes in oxidation and reduction in paddy soil layers during rice cropping. The mid-season aeration and drying-wetting alternation can stimulate N<inf>2</inf>O generation and emissions from paddy soils. Tillage and residue management practices can also affect nitrification and denitrification due to the change of soil characteristics. However, cultivation patterns do not have significant impacts on N<inf>2</inf>O emissions from paddy fields in current studies. Further research is needed to study the long-term effects of cultivations on N<inf>2</inf>O emissions. Most studies showed that N<inf>2</inf>O emissions decrease by incorporating biochar into paddy soils, but inconsistent results have also been reported. In addition, models (e.g., DNDC, CENTURY) are good options to simulate the effects of alternative agricultural practices on N<inf>2</inf>O emission from paddy fields and to identify potential strategies for climate change mitigation. In addition, the different effect of farming management practices on N<inf>2</inf>O emission may be presented based on the difference of many factors (e.g., climate conditions, soil types). An immense challenge to find ways to reduce N<inf>2</inf>O emission from paddy soils lies ahead for the scientific community and policy makers. Researchable priorities should be: 1) to implement exhaustive research on mechanisms that new agricultural management practices affect N<inf>2</inf>O generation and its emission pathways; 2) to assess effect of agricultural practices on the direct and indirect N<inf>2</inf>O emissions from paddy fields and their mechanisms; 3) to make in-depth studies on characteristics of N<inf>2</inf>O emission in technologies with integration of various farming practices; and 4) to simulate and forecast impacts of agricultural practices on N<inf>2</inf>O emissions in paddy ecosystems. Integrated farming approaches that exert a crucial role in the reduction of N<inf>2</inf>O emissions from paddy soils are necessary to be explored to mitigate the consequences of climate change on our planet. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:75
Main heading:Climate change
Controlled terms:Agricultural machinery - Agriculture - Climate models - Climatology - Cultivation - Decision making - Denitrification - Ecology - Ecosystems - Fertilizers - Irrigation - Nitrification - Nitrogen fertilizers - Nitrogen oxides - Soils
Uncontrolled terms:Agricultural management practice - Climate change mitigation - Fertilizer applications - Nitrification and denitrification - Nitrous oxide - Nitrous oxide emissions - Oxidation and reduction - Paddy fields
Classification code:443 Meteorology - 451 Air Pollution - 454.3 Ecology and Ecosystems - 483.1 Soils and Soil Mechanics - 802.2 Chemical Reactions - 804 Chemical Products Generally - 804.2 Inorganic Compounds - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 912.2 Management
DOI:10.11975/j.issn.1002-6819.2015.11.001
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 34>
Accession number:20152701006225
Title:Chaotic characteristic analysis of tool wear acoustic emission signal
Authors:Guan, Shan (1); Peng, Chang (1)
Author affiliation:(1) School of Mechanical Engineering, Northeast Dianli University, Jilin, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:60-65
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In metal cutting process, surface quality and dimensional accuracy of the work piece is affected by cutting-tool wear condition. So it is important to study the cutting-tool wear, especially in automation production. Cutting-tool wear is a complex process; it is affected by various factors like cutting parameters, material characteristics and cutting environment, etc. Metal cutting is a nonlinear system; there are a lot of non-stationary signals used in condition monitoring and fault diagnosis. Vibration, force and acoustic emission (AE) are the typical signal type widely used in cutting-tool wear research. In this paper, we chose AE signal to be the carrier in analyzing cutting-tool wear. AE is the class of phenomena where transient elastic waves are generated by the rapid release of energy when the materials are distorted or under the outside load. The AE signal produced by cutting -tool wear is high-frequency and the bandwidth is nearly 50 kHz-1 MHz, so it can weaken the influence of low-frequency noise like mechanical noise and ambient noise. The measured signal sometimes contains high-frequency noise. In this paper, chaos theory was used in analyzing the nonlinear characteristics of the AE signal. Chaos theory is sensitive to noise; therefore, noise reduction was done with the method based on empirical mode decomposition and wavelet (EMD-Wavelet) before computing. The signal were decomposed into several intrinsic mode functions which was from high-frequency to low-frequency by use of EMD, then it was used to determine the noise dominated intrinsic mode functions based on consecutive mean square error (CMSE) proposed by Boudraa and then restrained them. A new signal were reconstructed by adding the rest intrinsic mode functions together and a further and last de-noising was using wavelet to processing the new one in order to get more pure signal. Before extracting the chaotic character, an important step was to reconstruct a phase space from the de-noised signal. To get the phase space vector, two key parameters, delay time and embedding dimension, had to be determined. Method based on mutual-information was utilized in computing delay time and Cao method for embedding dimension. After reconstructing the phase space, the chaos attractor was presented which can obviously reflect the cutting-tool wear condition. The structure of the attractor differed with tool wear. In order to prove the effect of noise reduction, a comparison was done between attractors another one reconstructed from original signal. The attractor reconstructed from the purified signal was smoother than the noisy signal. To get accurate result, the correlation dimension was computed. The result showed that seemingly random AE signal has internal ordered state and there was a certain correspondence between the correlation dimension and tool wear. So the chaos character can be used in cutting-tool wear identification and the result can offer a reference for cutting-tool wear condition monitoring. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:14
Main heading:Cutting tools
Controlled terms:Acoustic emission testing - Acoustic noise - Bandwidth - Chaos theory - Computation theory - Condition monitoring - Cutting - Elastic waves - Fault detection - Functions - Mean square error - Metal analysis - Metal cutting - Phase space methods - Signal denoising - Signal processing - Tools - Vector spaces - Wavelet decomposition - Wear of materials
Uncontrolled terms:Acoustic emission signal - Attractor - Correlation dimensions - De-noising - Empirical Mode Decomposition - Nonlinear characteristics - Phase space reconstruction - Tool wear condition monitoring
Classification code:421 Strength of Building Materials; Mechanical Properties - 422 Strength of Building Materials; Test Equipment and Methods - 422.2 Strength of Building Materials : Test Methods - 531 Metallurgy and Metallography - 603 Machine Tools - 604.1 Metal Cutting - 605 Small Tools and Hardware - 706 Electric Transmission and Distribution - 716.1 Information Theory and Signal Processing - 731.1 Control Systems - 751 Acoustics, Noise. Sound - 801 Chemistry - 921 Mathematics - 921.3 Mathematical Transformations - 951 Materials Science
DOI:10.11975/j.issn.1002-6819.2015.11.009
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 35>
Accession number:20152701006260
Title:Changes of ultraweak photon emission of corn during germination under NaCl stress
Authors:Xi, Gang (1); Zhao, Yanyan (1); Liu, Kai (1); He, Ruirui (1)
Author affiliation:(1) Department of Applied Physics, Institute of Science, Xian University of Technology, Xi'an, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:308-314
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Biological ultraweak photon emission is divided into spontaneous photon emission and delayed photon emission. It is very important life information from living cells. The study of the ultraweak photon emission about germinating crop seeds is possible to provide a new method of sensitive, fast and nondestructive evaluation of the cell metabolism and functional status. The analysis technology of biological ultraweak photon emission plays an important role in many aspects such as the germination mechanism of seeds, the evaluation of salt tolerance and the identification of crop germplasm. In order to reveal the biological significance of the ultraweak photon emission from germinating corn seeds under salt stress, some corn seeds were placed in different concentrations of NaCl solution, and the changes of ultraweak photon emission in germinating corn seeds under the NaCl stress of different concentrations were studied in this paper. The results showed that the seed fresh quality and spontaneous photon emission from germinating corns in control group were gradually growing in the process of corn seed germination, and there was a positive correlation between the changes of seed quality fresh and spontaneous photon emission (correlation coefficient was 0.9614); the changes of spontaneous photon emission and fresh quality of germinating corn seed also showed a positive correlation under the NaCl stress of 50, 100 and 150 mmol/L (correlation coefficients were 0.9582, 0.9406 and 0.9389 respectively). The study also showed that NaCl stress inhibited the growth of the seed fresh quality and the increase of spontaneous photon emission in corn seeds during germination, and the higher the concentration of NaCl, the stronger the inhibition. The change of the spontaneous photon emission provides the information about the decrease of respiration metabolism and DNA synthesis in germinating corn under the stress of NaCl according to the biological significance of spontaneous photon emission. The study also showed that the delayed photon emission of germinating corn excited by blue LED had changed under NaCl stress, and in the control group, the kinetic parameters such as initial photon number and coherence time about delayed photon emission of germinating corn gradually increased with the germination time, and the integral strength of delayed photon emission of corn seeds increased rapidly in 2 days after absorption, then held steady. It was also found that NaCl stress inhibited the increase of the initial photon number and coherence time about delayed photon emission of germinating corn, and caused the integral strength of delayed photon emission from germinating corn seeds to decrease, the greater the concentration of NaCl, the smaller the integral strength of delayed photon emission. The changes of the kinetic parameters of delayed photon emission about germinating corn seeds showed that NaCl stress could cause reactive molecules in seeds cells to reduce, organization and metabolic order to become disordered, and cell function to decrease. These research results provide a reference for explaining the response mechanism about the germination of corn under salt stress. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:37
Main heading:Photons
Controlled terms:Cells - Crops - Cultivation - Cytology - Kinetic parameters - Metabolism - Nondestructive examination - Photonics - Physiology - Quality control - Salts - Seed - Stresses
Uncontrolled terms:Corn seeds - Germination - Photon emissions - Salt tolerance - Spontaneous photon emission
Classification code:421 Strength of Building Materials; Mechanical Properties - 461.2 Biological Materials and Tissue Engineering - 461.9 Biology - 712 Electronic and Thermionic Materials - 717 Optical Communication - 744 Lasers - 804.1 Organic Compounds - 821.3 Agricultural Methods - 821.4 Agricultural Products - 913.3 Quality Assurance and Control - 931 Classical Physics; Quantum Theory; Relativity - 931.3 Atomic and Molecular Physics
DOI:10.11975/j.issn.1002-6819.2015.11.044
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 36>
Accession number:20152701006247
Title:Probability locality preserving discriminant projections for plant recognition
Authors:Zhang, Shanwen (1); Wang, Xianfeng (1); Wang, Zhen (1); Zhang, Qiang (2)
Author affiliation:(1) Department of Engineering and Technology, Xijing University, Xi'an, China; (2) College of Plant Protection, Northwest A&F University, Yangling, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:215-220
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Study on the classification and recognition methods of plant species by using plant leaf images plays an important role in protecting plant species and ecological environment. Designing a computer-aided plant recognition system is necessary and useful since it can facilitate plants recognition and classification, and understanding and managing plant species. Compared with other plant recognition methods, such as cell and molecule biology methods, plant recognition and classification based on leaf image processing is becoming a popular trend. In protecting plant perspective, leaf images have been used by plant protection researchers to diagnose plant diseases and this method has been proven to be reliable for years. Each kind of plant leaf has its own features and carries large significant information that can be used to recognize and classify the origin or the type of plant. Leaf shape is a prominent feature that most people use to recognize and classify a plant. The features, such as leaf area, perimeter, diameter, physiological length and physiological width, are basic geometry information that can be extracted from the leaf shape. In addition, leaf color, textures and vein pattern are also considered as important classifying features. All these features are useful for recognizing and classifying plant. Because of the complex and diversity of plant leaf images and the differences between within-class leaf images, many classification and recognition methods that use color, shape and texture of the leaves cannot meet the need of the plant automatic identification system. The feature extraction and dimensional reduction is a key step to plant classification. The classical linear dimensional reduction methods can not effectively applied to leaf image processing because the plant leaf images are general nonlinear data. Manifold learning based recognition methods have been successfully applied to face recognition. Based on manifold learning, a probability locality preserving discriminant projections (PLPDP) method was proposed for plant recognition in this study. The method was to learn a linear transformation, and focuses only on the pairwise points where the two points were neighbors to each other. First, the classification probability of each sample was computed, and the weighted matrix was defined by local information, label information and classifying probability. Then objective function was redefined. Then, through minimizing the function, an optimal projection matrix could be preserved in the low-dimensional feature space, such as the distribution information contained in the original data. Compared with the popular dimensionality reduction methods, such as linear discriminant analysis (LDA), locality preserving projections (LPP), discriminant LPP (DLPP) and supervised LPP (SLPP), the proposed method took three kinds of information into account (i.e., local information, label information and classifying probability) and refined the weighted matrix, which not only contained neighborhood information of samples, but also could reflect the probability from which a sample was correctly classified when its K-nearest-neighbors were selected. After projection, the neighborhood relationship of the intra-class samples which possessed more classification probability could be preserved, and the considered pairwise points in within-class were as close as possible, while those in between different classes were as far as possible, in which the global optimum could be effectively obtained. Finally, the experimental results on the public plant leaf image database demonstrate the superiority of the proposed algorithm compared with other algorithms. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:21
Main heading:Classification (of information)
Controlled terms:Automation - Discriminant analysis - Face recognition - Feature extraction - Image classification - Image processing - Image retrieval - Linear transformations - Mathematical transformations - Matrix algebra - Nearest neighbor search - Physiology - Plants (botany) - Probability - Textures
Uncontrolled terms:Automatic identification system - Classification and recognition - Dimensionality reduction method - Linear discriminant analysis - Locality preserving projections - Locality-preserving - Neighborhood information - Plant recognition
Classification code:461.9 Biology - 716 Telecommunication; Radar, Radio and Television - 716.1 Information Theory and Signal Processing - 731 Automatic Control Principles and Applications - 732 Control Devices - 741 Light, Optics and Optical Devices - 921.1 Algebra - 921.3 Mathematical Transformations - 922 Statistical Methods - 922.1 Probability Theory - 933 Solid State Physics
DOI:10.11975/j.issn.1002-6819.2015.11.031
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 37>
Accession number:20152701006231
Title:Spatio-temporal distribution of cropland water use efficiency and influential factors in middle and east of China
Authors:Qiu, Kuanbiao (1); Cheng, Junfeng (2); Jia, Baoquan (3)
Author affiliation:(1) Key Laboratory of Soil and Water Conservation and Desertification Combating, College of Soil and Water Conservation, Beijing Forestry University, Beijing, China; (2) Shaanxi Qianweizhihui National Wetland Park Management Office, Baoji, China; (3) Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China; (4) Key Laboratory of Tree Breeding and Cultivation, State Forestry Administration, Beijing, China; (5) Research Centre of Urban Forestry, State Forestry Administration, Beijing, China
Corresponding author:Jia, Baoquan
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:103-109
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Water use efficiency (WUE) of vegetation is an important parameter coupling the carbon cycle with water flux in the terrestrial ecosystem, as far as to the whole earth. Under the background of climate change, WUE is likely sensitive to the climatic factors. But for cropland, cultivation, as well as the climate change, also exerts great influences on the long-term WUE. However, questions are still remained about the spatio-temporal distribution of WUE and its affecting factors, for example what factors significantly affect the cropland WUE inter-annual variations and whether the effects of these factors vary with different regions at regional scale. Therefore, in order to obtain the change characteristics of WUE and the influential factors, this study focused on the application of data from moderate-resolution imaging spectroradiometer (MODIS), estimated the cropland WUE, analyzed the spatio-temporal patterns and evaluated the effects of climate change and two kinds of cultivation, irrigation and fertilization in the cropland in the middle of east of China. The cropland multiyear averaged WUE and its dynamics were evaluated in five regions that were delineated according to the dynamics of crop planting structure including: Region I representing the area where the crop was dominated by wheat and corn with rapidly expanding maize planting area, Region II where the crop was dominated by wheat and corn with expanding planting area, Region III where the crop was dominated by wheat and rice with expanding planting, Region IV where the crop was dominated by rice with expanding rice planting area and Region V dominated by rice with shrinking rice planting area. Results showed that multiyear averaged WUE was the largest in the North China Plain, Shandong Peninsula and the coast region in Jiangsu, with an average value of 2.0 g/kg, while in the Northeast China Plain and Hilly Region of Southeastern, the multiyear averaged WUE was approximately below 1.5 g/kg. Generally, multiyear averaged WUE was higher in the northern dryland field rather than in the southern paddy field. During the period from 2003 to 2012, the cropland WUE had an increasing trend in the middle and east of China. Compared to the southern paddy field, the northern dryland field had a larger rise. The largest increasing trend was found in the North China Plain where the cropland WUE increased by 0.02 g/kg per year. The cropland WUE showed a decreasing trend in the Hilly Regions of Southeast, area between Yangtze River and Huaihe River and Sanjiang plain with the largest decreasing amplitude approximately -0.007 g/kg per year. Generally, the increasing trend was more prevalent in the northern dryland field rather than in the southern paddy field. Correlation analysis showed that precipitation, effective irrigated area and fertilization were significantly (P<0.05) correlated with WUE inter-annual variation in Region II, solar radiation and precipitation in Region III and annual average temperature in Region IV. For Region II, due to the high co-linearity between precipitation with effective irrigated area and fertilization, the effects of irrigation and fertilization seem to be negligible for the inter-annual variation of cropland WUE. In the northern dryland field, precipitation was the main factor, while precipitation and annual average temperature were the main factors in the southern paddy field. In the northern dryland field, precipitation significantly controlled cropland evapotranspiration, while in the southern paddy field, the gross primary productivity was strongly regulated by annual average temperature. It is indicated that the different effects of climate on cropland WUE in the middle and east part of China, which will be of great importance on the rational utilization of water resource and the sustainable development of ecological environment in cropland. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:26
Main heading:Climate change
Controlled terms:Carbon - Crops - Ecology - Efficiency - Image reconstruction - Irrigation - Plants (botany) - Radiometers - Satellite imagery - Sustainable development - Water resources - Water supply
Uncontrolled terms:Cropland - Fertilization - Gross primary productivity - Middle and east of China - Moderate resolution imaging spectroradiometer - Spatiotemporal distributions - Spatiotemporal patterns - Water use efficiency
Classification code:443 Meteorology - 444 Water Resources - 446.1 Water Supply Systems - 451 Air Pollution - 454.3 Ecology and Ecosystems - 461.9 Biology - 741 Light, Optics and Optical Devices - 804 Chemical Products Generally - 821.3 Agricultural Methods - 821.4 Agricultural Products - 911.2 Industrial Economics - 913.1 Production Engineering - 944.7 Radiation Measuring Instruments
DOI:10.11975/j.issn.1002-6819.2015.11.015
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 38>
Accession number:20152701006224
Title:Effect of mechanical compaction on soil micro-aggregate composition and stability of black soil
Authors:Lu, Qianqian (1); Wang, Enheng (1); Chen, Xiangwei (1)
Author affiliation:(1) College of Forestry, Northeast Forestry University, Harbin, China; (2) Open and Key Laboratory of Northeastern Forest Silviculture, Harbin, China
Corresponding author:Chen, Xiangwei
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:54-59
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Aggregates are secondary particles formed through the combination of mineral particles glued by organic and inorganic substances. Soil compaction caused by mechanical tillage practices mainly affects its structure and function by the dispersing, braking, re-proportioning, re-arranging and re-combining aggregates. Although mechanical compaction was reported to reduce the proportion of soil water stable aggregate with size smaller than 0.25 mm, how further impact of mechanical compaction on composition and stability of soil micro-aggregate is still unknown. Comparing to the study of soil macro-aggregates, research on soil micro-aggregates can contribute to a better understanding of disperse strength and structural performance of primary aggregates under particular conditions. Based on the cropland soil in the typical black soil region of Northeast China, the influence of mechanical compaction on soil micro-aggregate composition and stability was studied by measuring and analyzing the soil micro-aggregate distribution, mean weight soil specific area (MWSSA), fractal dimension (D) and dispersion coefficient at different soil depths (0-20 cm, >20-40 cm, and >40-80 cm). The results showed that mechanical compaction mainly reduced the proportion of macro-aggregate (≥0.25 mm) and increased the proportion of small-sized (<0.002 mm) micro-aggregate in the 0-20 cm soil depth. The MWSSA, D value and dispersion coefficient were significantly higher than control condition (P<0.05) when the number of mechanical compaction passes increased 12 times, indicating that repeated compaction could cause a significant reduction on soil micro-aggregate stability. In the soil depth >20-40 cm, mechanical compaction primarily affected the proportion of micro-aggregates with diameter of 0.05-0.25 mm and <0.002 mm. The MWSSA, and D value of soil micro-aggregates decreased significantly (P<0.05) when the mechanical compaction treatment was only 3 passes but the proportion of each size aggregate distributed uniformly. However, these measurements increased significantly when the compaction passes increased to 12 times (P<0.05), which also indicated that repeated compaction caused a significant reduction on soil micro-aggregate stability. The only difference was that a few times of compaction (3 passes) could promote the reunion of the small-sized micro-aggregates and extenuate the destruction of relative bigger sized micro-aggregates. Within the >40-80 cm soil layer, the proportion of middle-class micro-aggregates (>0.05-0.25 mm and >0.02-0.05 mm) reduced, but macro-aggregate (≥0.25 mm) and smaller sized micro-aggregate (<0.002 mm) increased, which resulted in a non-uniformed distribution pattern of different sized micro-aggregates. Soil MWSSA, D value and dispersion coefficient increased gradually with increasing the passes of traffic, indicating even few passes of compaction could significantly reduce the stability of the soil micro-aggregates, and the mechanical compaction had a significant cumulative effect on deeper soil layer (>40-80 cm). This result confirmed the former research conducted in this area with the same traffic machine. The proportion of <0.002 mm micro-aggregate (clay content) had a highly significant correlation with the other micro-aggregates characteristic indices (P<0.05), which suggested to be an effective parameter to reflect soil micro-aggregates dispersion, reunion and stability. In summary, mechanical tillage compaction tended to increase the smaller sized micro-aggregate composition and reduce its stability, especially for the deeper soil (>40-80 cm). The findings showed that cumulative compaction effects on subsurface area and deeper soil layer can not be neglected, and may serve as theoretical basis for scientifically evaluating soil compaction and quality evolution in typical black soil region. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:21
Main heading:Agglomeration
Controlled terms:Aggregates - Agricultural machinery - Agriculture - Compaction - Dispersions - Fractal dimension - Fractals - Machinery - Soil mechanics - Soil moisture - Soils - Stability
Uncontrolled terms:Black soil region of northeast chinas - Characteristic indices - Dispersion coefficient - Distribution patterns - Fractal dimensions (d) - Microaggregates - Soil water-stable aggregates - Structural performance
Classification code:406 Highway Engineering - 483.1 Soils and Soil Mechanics - 601 Mechanical Design - 801 Chemistry - 802.3 Chemical Operations - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 821.1 Agricultural Machinery and Equipment - 921 Mathematics - 931 Classical Physics; Quantum Theory; Relativity - 951 Materials Science - 961 Systems Science
DOI:10.11975/j.issn.1002-6819.2015.11.008
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 39>
Accession number:20152701006253
Title:Optimizing preparation of activated carbons from rice husk by K<inf>2</inf>CO<inf>3</inf> chemical activation
Authors:Liao, Qinhong (1); Li, Huihe (1); Liu, Yiqing (1); Liao, Linzheng (1)
Author affiliation:(1) College of Life Science and Forestry, Chongqing University of Arts and Sciences, Chongqing, China; (2) Special Plants Research Institution, Chongqing University of Arts and Sciences, Chongqing, China
Corresponding author:Li, Huihe
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:256-261
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The purpose of the present study was to realize the resource utilization of agricultural byproduct. In this paper, we used rice husk as materials for producing activated carbon. Five factors which affected the yield and iodine absorption performance of rice husk-based activated carbon were sifted and optimized by Plackett-Burman (P-B) and Central Composite Design (CCD). Based on those, the prediction models of yield and iodine adsorption rate were determined and validated. The measurement of iodine absorption rate was based on the method of the GB/T 12496.1-12496.22-1999. The results showed that the determination coefficients (R<sup>2</sup>) of regression equations which established for the yield and iodine adsorption rate of activated carbon samples were 0.90 and 0.85, respectively. The first main factor which influenced the yield of activated carbon was activation temperature followed by activation time and concentration of K<inf>2</inf>CO<inf>3</inf>.For the iodine adsorption rate of activated carbon, activation temperature still played an important role in the preparation process, and the next were the concentration of K<inf>2</inf>CO<inf>3</inf> and activation time. The impregnation volume ratio and impregnation time had little influence on the performance of rice husk-based activated carbon. The prediction models which were established by the CCD had a highly significant correlation (P<0.0001) and the determination coefficients (R<sup>2</sup>) reached 0.92 and 0.90, respectively. There was a strong interaction between the activation temperature and activation time. The response surface analysis indicated that when the activation time was at the center value of 0.92 h and the concentration of K<inf>2</inf>CO<inf>3</inf> remained a constant, the iodine adsorption rate increased with the rise of activation temperature. It can be well illustrated that high activation temperature can promote the chemical reaction. However, the iodine adsorption rate decreased with the extension of activation time when the concentration of K<inf>2</inf>CO<inf>3</inf> was at the center value of 1.5 mol/L and activation temperature remained a constant. This was because that long activation time made the micropore of samples sintered, thus it affected the adsorption performance of rice husk-based activated carbon. With the increased concentration of K<inf>2</inf>CO<inf>3</inf>, the iodine adsorption rate showed a gradually increasing trend when the activation temperature was at the center value of 1098 K and activation time remained a constant. It was the reason that more active agent can increase the contact area, which accelerated the reaction distinctively. The optimal conditions were that the rice husk was infused in the K<inf>2</inf>CO<inf>3</inf> solution with concentration and impregnation volume ratio (K<inf>2</inf>CO<inf>3</inf>/rice husk) of 1.95 mol/L and 3, respectively after impregnating for 11 h, they were heated for 1.17 h at 1173 K. The prediction value of yield and iodine adsorption rate were 13.61%, 1058.83 mg/g, and the adequacy of the model equation for predicting the optimum response values was verified effectively by the experiment, and the experimental values (14.53%, 1021.30 mg/g) agreed with the predicted values of the model equation with 6.33%, 3.67% deviation, respectively. Our results indicated that optimizing the preparation of rice husk-based activated carbon by using CCD was reliable. This study can provide an important reference for the preparation of activated carbons from rice husk in the industrial production. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:25
Main heading:Chemical activation
Controlled terms:Activated carbon - Activation analysis - Adsorption - Carbon - Forecasting - Impregnation - Iodine - Sintering - Surface analysis - Technology - Wastes
Uncontrolled terms:Activation temperatures - Agricultural by-products - Central composite designs - Determination coefficients - Iodine adsorption - Plackett-Burman - Response surface analysis - Yield
Classification code:423 Non Mechanical Properties and Tests of Building Materials - 452.3 Industrial Wastes - 801 Chemistry - 802.3 Chemical Operations - 804 Chemical Products Generally - 901 Engineering Profession - 921 Mathematics - 951 Materials Science
DOI:10.11975/j.issn.1002-6819.2015.11.037
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 40>
Accession number:20152701006219
Title:Parameter optimization of sugar beet digging device with disc type
Authors:Wang, Fangyan (1); Zhang, Dongxing (2)
Author affiliation:(1) College of Mechanical and Electrical Engineering, Qingdao Agricultural University, Qingdao, China; (2) College of Engineering, China Agricultural University, Beijing, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:17-23
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:At present, the sugar beet harvest is still hand operation in China, which results in labor intensity and low efficiency. Therefore, the development of sugar beet harvester is an efficient approach to change the traditional way of harvesting sugar beet in China. Since harvesting is the crucial process, the harvest device has played important role in the process of the sugar beet harvest. The digging component is a major operating unit of harvest machine and it can influence the harvest performance, working resistance and power consumption of machine directly. As such the digging device is the bottleneck of the development of mechanization for sugar beet harvesting. As a sugar beet harvester machine, a disc type digging device that can break and turn soil, and separate sugar beet from soil completely, has some advantages for its simple structure, less digging volume, small digging resistance. In addition, it can also reduce harvest time and labors. All of those give disc type digging device a great superiority in the field of the digging device of harvest machine. To solve the problem of harvest blocking, the performance parameters of disc digging device were obtained by combining the structure and working principle, which affected its adaptability and stability, such as opening angle, deflection angle and digging depth. And the motion equation of disc blade was set by analyzing the relationship between the parameters and movement mechanism of the digging system theoretically. In order to design a more reasonable digging device with better digging effect for the disc type digging harvester of sugar beet, an orthogonal experiment and weighted score method were carried out. The comprehensive score index was an important technical index to be considered for the overall performance, and factors directly affecting the overall performance included clay content, break rate and damage rate. To improve the working performance of disc type digging device, three variables were selected as the experimental factors, i.e. opening angle, the deflection angle and digging depth of digging device. With three factors and three levels orthogonal experiment, the influences of each factor on the harvest performance were reported, and optimal technique parameters were obtained. The results showed there was a large influence of digging depth on clay content and break rate, and an interaction influence of opening angle and digging depth on the break rate for sugar beet, while no significant influence of deflection angle on these two indicators. However, there was a negligible effect on damage rate from each factor. With the opening angle of 15°, the deflection angle of 35° and digging depth of 90 mm, the clay rates of sugar beet was 2.7%. There was no break or damage for sugar beet, with the opening angle of 19°, the deflection angle of 30° and digging depth of 120 mm. For many indicators, comparative analysis was used by synthetically judgment, which was an important method of economic analysis for the agricultural technology. There was a significant effect on comprehensive score index from opening angle, digging depth and those interaction term. The optimum working conditions were: opening angle 15°, deflection angle 30°, and digging depth 120 mm. The research can provide references on optimizing the harvester machine structure, and improving the performance of digging device. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:24
Main heading:Disks (machine components)
Controlled terms:Agricultural machinery - Agriculture - Deflection (structures) - Economic analysis - Equations of motion - Harvesters - Harvesting - Optimization - Sugar beets
Uncontrolled terms:Agricultural technologies - Digging device - Optimum working conditions - Orthogonal experiment - Parameter optimization - Performance parameters - Performance tests - Sugar beet harvesters
Classification code:421 Strength of Building Materials; Mechanical Properties - 601.2 Machine Components - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 911.2 Industrial Economics - 921.2 Calculus - 921.5 Optimization Techniques
DOI:10.11975/j.issn.1002-6819.2015.11.003
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 41>
Accession number:20152701006233
Title:Optimization of soil water characteristic curves parameters by modified firefly algorithm
Authors:Fu, Qiang (1); Jiang, Ruiqi (1); Wang, Zilong (1); Li, Tianxiao (1)
Author affiliation:(1) College of Water Conservancy and Architecture, Northeast Agricultural University, Harbin, China
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:117-122
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:In accurate estimation of parameters of soil water characteristic curves can cause simulation results of soil moisture models. This paper introduced firefly algorithm to solve the nonlinear fitting problem of soil water characteristic curve model (Van Genuchten) parameters. In the algorithm principle, the force of attraction and light are based on the distance between different individuals, based on which the whole population is divided into a number of subgroups at the beginning, and every sub-population gathered around local optimal value. All sub-population can optimize at the same time, improving the efficiency, and the global optimal solution is found between all these local optimal values. Compared with the particle swarm algorithm, the firefly algorithm does not use perception such as individual best position, the global optimal position to control calculation, which avoids the potential defects such as premature convergence. In addition, the algorithm dose not set speed for fireflies, which avoids the problem that the speed exceeds a threshold. But, when firefly individuals approach the optimal value, it is likely to move longer than the distance between the individual and the optimal value, therefore resulting in the jump-over of the optimal value and reaching the other side. If this situation appears repeatedly, it will affect the convergence speed and accuracy of algorithm. So in this paper we turned the fixed step length into a variant step length that changed according to the between-firefly distance, and thus the firefly algorithm had a better global optimization ability at the beginning and rapidly found the position adjacent to the optimal value region, in the end it had a good local search ability and was able to find the overall optimal value. The test samples came from test field of College of Water Conservancy and Architecture in Northeast Agricultural University (126°45'32″E, 45°44'41″N), China. Black soil in Harbin area can represent the southern area of Heilongjiang. The samples were taken from four adjacent areas with a size of 10m×10 m. Sampling depth was 0-20, >20-40, >40-60, >60-100, >100-140, and >140-180 cm, respectively. The relation of the soil suction and the soil moisture content was measured by a hypothermia supercentrifuge. The standard particle swarm algorithm, the standard genetic algorithm, the improved algorithm and the standard firefly algorithm were used in this paper to simulate the process of black soil and clay moisture desorption at different depths, and the relevant parameters and volumetric water content were obtained from calculation. The simulation results showed that simulation results from standard firefly algorithm and improved firefly algorithm were of high precision, in good agreement with the experimental results (the average error was less than 1%, the maximum relative error was only about 2%)by comparing calculating soil moisture characteristic curve with the experimental one. Firefly algorithm accuracy was higher than that of particle swarm algorithm and genetic algorithm, the improved firefly algorithm began to converge after about 23 iterations, the improved firefly algorithm was obviously better than the traditional ones. It was viable to use the firefly algorithm to solve this kind of nonlinear optimization problem, especially for high precision, accuracy or provide accurate basis for follow-up studies. For the surface black soil (0-20 cm) and clay in the lower layer (>20-40 cm), when the parameter range were [0.0251, 0.0496] and [0.0021, 0.0110], the maximum deviation of volumetric water content simulation results was less than 5%, indicating that the simulation precision was high. Fitting results can accurately reflect the characteristics of black soil in Harbin area, and the result of the reciprocal of air-entering value conformed to the actual situation, reflecting the characteristics of less clay and light texture in the surface layer, more clay and heavy texture in parent material horizon. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:23
Main heading:Parameter estimation
Controlled terms:Algorithms - Bioluminescence - Curve fitting - Fire protection - Genetic algorithms - Global optimization - Moisture - Nonlinear programming - Optimal systems - Optimization - Soil moisture - Soil structure interactions - Soils - Textures - Water content - Water management
Uncontrolled terms:Firefly algorithms - Parameter optimization - Soil-water characteristic curve - Step length - Van Genuchten model
Classification code:444 Water Resources - 483.1 Soils and Soil Mechanics - 483.2 Foundations - 723 Computer Software, Data Handling and Applications - 731.1 Control Systems - 741.1 Light/Optics - 801.4 Physical Chemistry - 914.2 Fires and Fire Protection - 921 Mathematics - 933 Solid State Physics
DOI:10.11975/j.issn.1002-6819.2015.11.017
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 42>
Accession number:20152701006237
Title:Rational irrigation and nitrogen supply methods improving root growth and yield of maize
Authors:Qi, Dongliang (1); Hu, Tiantian (1); Wu, Xue (1); Niu, Xiaoli (1)
Author affiliation:(1) College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, China
Corresponding author:Hu, Tiantian
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:144-149
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Ridge-furrow irrigation is wildly used in crop production. Few studies focus on the interaction effect of furrow irrigation methods and nitrogen supply method on crops, especially for root distribution. In this study, the coupling effects of different furrow irrigation and nitrogen supply methods on growth and distribution of root and yield for maize were investigated. Ridge-furrow irrigation was conducted in field in 2011 with spring maize of Jinsui4.Three furrow irrigation and N-fertilizer supply methods were designed including alternate, fixed and conventional furrow irrigation, and alternate, fixed and conventional nitrogen supply. Each treatment was replicated three times and the plot was layout by complete randomized design. The root length and weight beneath the plant canopy, south and north of the plant in the soil layers of 0-100 cm were measured at the growth stages of tasseling, filling and maturity with sampling at 20 cm as an interval. Grain yield was also measured at the harvest. The results showed that only root length and the total dry weight of the plant in the south were significantly influenced by nitrogen supply methods. The total root length and root length of the plant in north was influenced by the interaction of irrigation and nitrogen supply methods. The total root length of plants under the alternate furrow irrigation was kept larger in the growth period. Meanwhile, under the alternative furrow irrigation and conventional N-supply, the root length of the plant in north, south and beneath the canopy in the soil layer of 0-100 cm, as well as total root length and total root surface area at the filling stage were larger, thereby resulted in highest yield of 11524 kg/ hm<sup>2</sup>. In contrast, total root length as well as yield of fixed furrow irrigation with fixed nitrogen supply was smallest. The root length under the plant in the soil layer of 0-100 cm of the alternate furrow irrigation with alternate nitrogen supply was as large as the alternate furrow irrigation with conventional nitrogen supply. The root length ratio in the soil layer of 0-40 cm to 0-100 cm was larger under different treatments and the largest one was found in the treatment of alternate furrow irrigation combined with conventional nitrogen supply. The results suggested that root growth and distribution are more susceptible to irrigation methods. Regulation for root growth and distribution of maize through different irrigation and nitrogen supply methods should be mainly in the soil layer of 0-40 cm. Yield and root growth of maize can improved by alternate furrow irrigation with conventional nitrogen supply but inhibited by fixed furrow irrigation with fixed nitrogen supply. Alternate furrow irrigation with alternate nitrogen supply is only inferior to alternate furrow irrigation with conventional nitrogen supply in improving the yield and root growth of maize, but superior to the other treatments. Thus, alternate furrow irrigation combined with conventional nitrogen supply is considered an optimum coupling pattern of irrigation and nitrogen supply method under the ridge-furrow irrigation. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:25
Main heading:Irrigation
Controlled terms:Crops - Cultivation - Fertilizers - Forestry - Nitrogen - Nitrogen fertilizers - Soils
Uncontrolled terms:Alternate furrow irrigation - Different treatments - Furrow irrigation methods - Interaction effect - Maize - Nitrogen supply - Root growth - Yield
Classification code:483.1 Soils and Soil Mechanics - 804 Chemical Products Generally - 821 Agricultural Equipment and Methods; Vegetation and Pest Control
DOI:10.11975/j.issn.1002-6819.2015.11.021
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 43>
Accession number:20152701006251
Title:Optimal ratios of oyster to Gracilaria improving removal efficiency of nitrogen nutrients in aquaculture wastewater
Authors:Li, Meng (1); Song, Xiefa (1); Sun, Guoxiang (2); Ma, Xiaona (2); Liu, Ying (2)
Author affiliation:(1) Fisheries College, Ocean University of China, Qingdao, China; (2) Institute of Oceanology, Chinese Academy of Science, Qingdao, China; (3) University of Chinese Academy of Sciences, Beijing, China; (4) National & Local Joint Engineering Laboratory of Ecological Mariculture, Qingdao, China
Corresponding author:Liu, Ying
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:243-248
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:Currently, intensive marine aquaculture has been widely adopted to obtain higher yields of aquatic food production. However, the effluent unfiltered wastewater, including organic and inorganic nitrogen and phosphorous can damage the physiology of farmed species and cause hyper-trophication of adjacent ecosystems. Using bivalve mollusc and macroalgae to purify wastewater before discharged is gaining extensive attention due to their cost effect and efficient features. The present study was conducted to investigate the effectiveness of an oyster-Gracilaria system. The study focused on the effects of Gracilaria lemaneiformis densities and Crassostrea gigas to Gracilaria lemaneiformis ratios. This experiment contained two parts. In the first part, four densities of Gracilaria (0.8, 1.6, 2.4 and 3.2 g/L) were set up. The results showed that all the four treatments had a low total ammonia nitrogen removal rate (less than 40%) before 48 h. However, treatments of 2.4 g/L and 3.2 g/L had a relative high TAN removal rate in 60 h (54.34% and 67.70%, respectively), 72 h (39.77% and 48.27%, respectively). Gracilaria of 1.6 g/L and 2.4 g/L removed relative more NO<inf>2</inf>-N in 6 h (56.64% and 55.26%), and in 12 h. In comparison, 2.4 g/L had a significant higher (P<0.05) NO<inf>2</inf>-N removal rate (57.33%) than other groups. Significant difference (P<0.05) of NO<inf>3</inf>-N removal rate occurred in 6, 18 and 72 h, with the highest removal rate in sets of 3.2 g/L (11.72%), 2.4 g/L (15.65%) and 2.4 g/L (7.61%), respectively. In the second part, a two-factor experiment was designed. Three gradient densities of oyster (1.6, 2.4, 3.2 g/L) and Gracilaria were set up and combined to each other. Results showed that 2.4 g/L oyster and 2.4 g/L Gracilaria lemaneiformis combination had higher NO<inf>2</inf>-N removal rate (40.29%) than other treatments. There were significant (P<0.05) interaction on TAN removal efficiency between the densities of oyster and Gracilaria lemaneiformis and Gracilaria lemaneiformis played a leading role (Gracilaria of 2.4 g/L removed 74.44% of TAN). The combination of 2.4 g/L oyster and 1.6 g/L Gracilaria lemaneiformis had better NO<inf>3</inf>-N removal rates, while there was no significant (P>0.05) difference with Gracilaria lemaneiformis of 2.4 g/L. Therefore, both oyster and Gracilaria lemaneiformis had the best efficiency in treating wastewater at the density of 2.4 g/L (Oyster: Gracilaria=1:1). ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:22
Main heading:Nitrogen removal
Controlled terms:Aquaculture - Efficiency - Effluents - Molluscs - Nitrogen - Shellfish - Wastewater - Wastewater treatment
Uncontrolled terms:Aquaculture wastewater - Atlantic salmon - Crassostrea gigas - Gracilaria lemaneiformis - Inorganic nitrogen - Ratio - Removal efficiencies - Total ammonia nitrogens
Classification code:452.3 Industrial Wastes - 452.4 Industrial Wastes Treatment and Disposal - 461.9 Biology - 471 Marine Science and Oceanography - 471.5 Sea as Source of Minerals and Food - 802.2 Chemical Reactions - 804 Chemical Products Generally - 913.1 Production Engineering
DOI:10.11975/j.issn.1002-6819.2015.11.035
Database:Compendex
Compilation and indexing terms, Copyright 2015 Elsevier Inc.
<RECORD 44>
Accession number:20152701006229
Title:Optimization of impact sprinkler sub-nozzle parameters of elevation angle and position
Authors:Wang, Xuan (1); Li, Guang (1); Guo, Congcong (1); Han, Wenting (1); Yao, Xiaoming (1); Sun, Yu (3)
Author affiliation:(1) College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, China; (2) Institute of Soil and Water Conservation, Northwest A&F University, Yangling, China; (3) College of Information Science and Engineering, Shanxi Agricultural University, Taigu, China
Corresponding author:Han, Wenting
Source title:Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
Abbreviated source title:Nongye Gongcheng Xuebao
Volume:31
Issue:11
Issue date:June 1, 2015
Publication year:2015
Pages:89-95
Language:Chinese
ISSN:10026819
CODEN:NGOXEO
Document type:Journal article (JA)
Publisher:Chinese Society of Agricultural Engineering
Abstract:The chief function of sub-nozzle of impact sprinkler is to increase the near precipitation depth, thereby improving the uniformity of sprinkler irrigation. In this study, flow field simulation combined with experimental validation method was applied to optimize the key structural parameters (elevation angle and position) of impact sprinkler. Nine kinds of elevation angles and positions of sub-nozzle combinations were designed with the established three-dimensional structures of the impact sprinkler by Pro/E software. The three-dimensional inner flow channel model of impact sprinkler with nine kinds of sub-nozzle structure was established. The inner flow channel simulations of all kinds of impact sprinkler were performed by FLUENT of Computational Fluid Dynamics (CFD) software. Considering structural feature, the precision requirement, the procession quality, and the cost of product, the SLA RPT (Stereo lithography Apparatus Rapid Prototyping Technology) was selected to prototype the impact sprinkler with nine kinds of sub-nozzle. The nine kinds of models were processed into samples for experimental verification. Under the rectangular combinations, four interpolation methods (distance interpolation method, linear interpolation method, cubic interpolation method and cubic spline interpolation method) were used to calculate the Christiansen uniformity coefficient and nine kinds of water pressure distribution models were established by Sprinkler 3D software in two-dimensional interpolation method. The result showed that the impact sprinklers with sixth sub-nozzle (position parameter of 19.8 mm, the elevation angle parameter of 18°) performed more reliable. The study about sub-nozzle of impact sprinkler's structural parameters improved the nozzle near water distribution effectively. Its flow rate of simulation was biggest. The yield of water distribution in 2-12 m could maintain good uniformity. And the sprinkler range of the sixth sub-nozzle was more than 14 m, better than before and increased by more than 2 m. The sprinkler irrigation uniformity was calculated with the four different interpolation methods and results were increased obviously. Under the pressure of 250 and 300 kPa (especially the pressure of 300 kPa), the Christiansen uniformity coefficient both was more than 80%, which was an increase of 4% and 5% above than before. With the increase of the pressure, Christiansen uniformity coefficient was still consistent generally. The structural parameters of sub-nozzle (position parameter of 19.8 mm and the elevation angle parameter of 18°) of impact sprinklers were more reasonable. This study provides valuable information for structural design of sub-nozzle, impact sprinkler and sprinkler system optimization. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Number of references:18
Main heading:Sprinkler systems (irrigation)
Controlled terms:Channel flow - Computational fluid dynamics - High pressure effects - Hose - Interpolation - Irrigation - Nozzle design - Nozzles - Optimization - Radio communication - Structural design - Water supply systems
Uncontrolled terms:Cubic spline interpolation method - Fluent simulation - Impact sprinklers - Parameter - Rapid prototyping technology - Sprinkler irrigation - Stereo-lithography apparatus - Two-dimensional interpolation methods
Classification code:408.1 Structural Design, General - 446.1 Water Supply Systems - 619.1 Pipe, Piping and Pipelines - 631.1 Fluid Flow, General - 716.3 Radio Systems and Equipment - 821.1 Agricultural Machinery and Equipment - 821.3 Agricultural Methods - 921.5 Optimization Techniques - 921.6 Numerical Methods - 931.2 Physical Properties of Gases, Liquids and Solids
DOI:10.11975/j.issn.1002-6819.2015.11.013
Database:Compendex
Compilation and indexing terms, Copyright 2015 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
- 地址 北京朝阳区麦子店街41号
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- Bioresource Technology
- Industrial Crops and Products
- Biomass & Bioenergy
- Biosystems Engineering
- Aquacultural Engineering
- International Journal of Agricultural and Biological Engineering
- Journal of Irrigation and Drainage Engineering
- Paddy and Water Environment
- Journal of Agricultural Engineering
- Transactions of the ASABE
- Revista Brasileira de Engenharia Agricola e Ambiental
- Applied Engineering in Agriculture
- Engenharia Agricola
- AMA-Agricultural Mechanization in Asia Africa and Latin America
- 中华人民共和国农业农村部-MARA
- 中国科学技术协会CAST
- 国家新闻出版署
- 中华人民共和国科学技术部
- 国家自然科学基金委员会
- U.S. DEPARTMENT OF AGRICULTURE
- CIGR
- ASABE
- EurAgEng-European Society for Agricultural Engineers
- American Society of Agronomy
- Crop Science Society of America
- Soil Science Society of America
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