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Solar greenhouse is one of the most important horticultural facilities in China. A great contribution has been made to produce fruits and vegetables in winter in northern China. Among them, the material of the south roof is usually plastic films with high light transmittance. The heat preservation quilt can also be used with better thermal insulation performance on the south roof, in order to reduce the heat loss in the low temperature outdoor environment at night. However, artificial management cannot fully meet large-scale production, due to the time-consuming and laborious in the large area of heat preservation quilt. Therefore, the heat preservation quilt can be accomplished using rolling machine at present. A fixed heat preservation quilt is usually laid between the rolling machine and the covering plastic film, in order to prevent the rolling machine from damaging the covering plastic film of the south roof during actual work. Specifically, the fixed heat preservation quilt is located in the center of the east-west length of the solar greenhouse. The sunlight can be blocked into the inside solar greenhouse in the daytime. The resulting shadow can move in the solar greenhouse over time, inevitably leading to the indoor light, temperature distribution, and crop yield. In this study, a calculation model was proposed for the shadow width of the fixed heat preservation quilt, according to the theory of direct solar radiation. A series of tests were also performed on the indoor light and temperature under the fixed heat preservation quilt. The experimental solar greenhouse was selected in Hongke Farm (39.6°N, 116.0°E), Fangshan District, Beijing. The results show that the average photosynthetic photon flux density (PPFD) was 198 μmol/(m² ·s) under the fixed heat preservation quilt. PPFD gradually increased with the center of the fixed heat preservation quilt moving on both sides. The average PPFD was greater than 400 μmol/(m² ·s) at a position greater than 3.6 m from the center of the fixed heat preservation quilt. Meanwhile, the light cumulant at the distance of 4.8 m increased by more than 130%, compared with the directly underneath fixed heat preservation quilt. In the daytime, the indoor air temperature, wall temperature and soil temperature directly below the fixed heat preservation quilt were 2.2, 5.8 and 2.3 ℃ lower than those on both sides of the quilt. Solar energy was collected and stored in the daytime, and then released heat at night, because the walls and the soil were the heat storage media. As a result, the higher temperature at night was achieved in the walls and the soil that received strong sunlight in the daytime. At night, the maximum wall temperature and the soil temperature directly below the fixed heat preservation quilt were 1.2 and 1.3 ℃ lower than those on both sides of the quilt. There was 14.3 kg average yield reduction of tomato in each furrow under the fixed heat preservation quilt, which was 36.2% than before. The average reduction of plant stem thickness was 2.0-4.0 mm. The shadow width was mainly affected by the illumination time, the geographical location, the orientation and the structure of the solar greenhouse. The shadow width decreased first and then increased over time in the daytime. The shadow width was the smallest at noon. The average shadow width of the solar greenhouse in the western region was larger than that in the eastern. Once the orientation of the solar greenhouse gradually changed from southwest to south-east, the shadow width decreased in the morning and increased in the afternoon. When the greenhouse azimuth was in range of -9° to 9°, the maximum difference of the average shadow width was less than 10.0%. Light and temperature are the important influencing factors on the normal growth of crops. Therefore, it is necessary to rationalize the management of the fixed heat preservation quilt. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Monochamus alternatus and Arhopalus rusticus are two important trunk-destroying pests on pine trees. Timely acquisition of their changing trends is required to precisely prevent and control of insect pests in pine forests. In this study, a remote intelligent monitoring system was constructed using machine vision, including the trapping module, the beetle detection, and the system web end. The trapping module was usually placed in the key areas of pine forests to capture the longicorn beetles, and then the images of the beetles were timely collected by cameras. The lightweight detection model (GMWYOLOv5s) was deployed to recognize and count the longhorn beetles at the edge using the deep learning YOLOv5s model. The detection data was presented on the web end via the wireless transmission for the better traceability of beetles’ distribution. The improved YOLOv5s model was used in the detection module to detect the different categories of longhorn beetles. The specific procedures were as follows. Firstly, the Ghost module was selected as the YOLOv5s backbone network to reduce the number of model parameters, and then a lightweight network was constructed. Secondly, the multi-scale detection mechanism was introduced into the neck network for the dependency relationship between the deep semantics and the shallow semantics multiscale detection information. The feature layer weights of the shallow network were benefited to increase the detection capability of the tiny targets. Finally, the regression loss function of WIoU (wise intersection over union) bounding box was introduced to optimize the target for the high localization accuracy of longhorn beetles. The experimental results show that the better performance was achieved in the intelligent monitoring system. Ghost module was introduced into the detection module to reduce the model size by 6.9 M and the parameter number by 47.6%. The multi-scale detection was improved the precision and recall by 0.7% and 0.4%, respectively. The mAP0.5 increased to 96.4% with the introduction of WIoU loss function. The GMW-YOLOv5s model was integrated with three improvement methods to detect the longhorn beetles. The precision and recall rate of the improved model were 94.4% and 93.6%, respectively. The mean average precision reached 96.2% under IoU=0.5 (mAP0.5), which was higher than that of the original. The improved model shared the better image feature learning and object detection, indicating the superior performance in the detection of small objects. The comparison was also implemented with many mainstream target detection models, including Faster-RCNN, SSD, YOLOX, YOLOv7-tiny, YOLOv5n, and YOLOv5s. The indicators of GMW-YOLOv5s model were improved, such as the precision, recall and mAP0.5. An accurate detection was achieved in the position of longhorn beetles, especially in the densely distributed scenes. In addition, the improved model was used to effectively distinguish some targets, and then avoid missed the detections. A single inference time of 1.4 s and a model size of 9.3 M were suitable for the deployment on the edge devices with limited computational resources, which was fully met the accuracy and intelligence requirements of the longicorn beetle detection task. Furthermore, the mean average precision and recall were 99.0%, and 98.7% in the two types of longicorn beetles counting respectively. The model and manual counts were relatively close to each other. There was the low number of omissions and misdetections, indicating the less error in counting the longicorn beetles of the image. The monitoring system can be expected to regularly and automatically collect the beetle images on a regular basis, and then accurately detect and count them at the edge end. The trend of the number of longhorn beetles can also be viewed through the system web interface. Therefore, it is of great significance for the remote intelligent monitoring of longhorn beetles in the trap scenarios, particularly for the higher intelligent level of forest pest control. [ABSTRACT FROM AUTHOR]

Hebei Province has been one of the most important parts of Beijing-Tianjin-Hebei region in China. But, the economic development of Hebei Province is largely lagging behind Beijing and Tianjin. Therefore, it is very necessary to tap the vitality of regional economic development in Hebei Province. Since the reform and opening up, it is highly urgent to balance between urban and rural development in many regions of China. Rural areas in Hebei Province have been limited to two difficulties in the economic development. This study aims to improve the relationship between rural regional functions for the optimal rural regional space, in order to ultimately promote the effective connection between poverty alleviation achievements and rural revitalization, particularly for the better coordinated development between regions and between urban and rural areas. Taking 121 counties (including county-level cities) in Hebei Province as the research unit, the evaluation index system of rural regional multi-function was constructed from four dimensions of agricultural production function, non-agricultural production function, living function and ecological security function. The comprehensive evaluation was used to measure the value of rural regional function. Then, the ArcGIS natural discontinuity point and global spatial autocorrelation models were used to reveal the spatial differentiation characteristics of rural regional multi-function. The symbiosis theory and model were selected to explore the symbiosis mode among rural territory multi functions, in order to realize the spatial division of rural territory function by integrating the dominant function, short board function and symbiosis mode type of rural territory multi-functions. The results show that: 1) There was an outstanding multi-functional spatial differentiation and agglomeration characteristics of rural territory. Some differences were found in the agricultural production functions between the north and the south in rural areas. The rural areas with the higher non-agricultural production functions were close to the Beijing and Tianjin areas or rich in ore resources. By contrast, the areas with the lower functions were distributed in the northern mountainous with the sparse population and backward economy. The living function of rural areas presented the spatial distribution characteristics of the high value in the southeast and low in the northwest. There was the strong ecological security function in the north, but the weak in the south. 2) There were the multiple symbiosis modes among the multi-functions of rural territory. Two function symbiosis mode was in reverse symmetrical symbiosis: the agricultural production and non-agricultural production function, agricultural production and ecological security function. The symbiotic mode of two functions was in the parasitic mode: the agricultural production and living function, non-agricultural production and living function, non-agricultural production and ecological function. Two function symbiosis mode was in positive asymmetric symbiosis: the residential life and ecological security function. 3) The rural territory were divided into four primary functional areas: the polarization, dominant, lack, and comprehensive development area, where 16 secondary functional types were subdivided. As such, the corresponding development strategies were proposed for the various functional areas. Studies have shown that rural regional multi-functions have certain spatial heterogeneity, and there are multiple symbiotic relationships among functions. In the decision-making of rural regional development, it is necessary to clarify the spatial differentiation characteristics and grasp the internal symbiotic relationship among rural regional multifunctions, so as to provide more scientific zoning optimization strategies. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Behavior characteristics of micro-bubbles are still elusive during operation along the labyrinth channel in micro/nano aeration drip irrigation. This study aims to clarify the presence and movement state of micro-bubbles under various inlet pressures along the labyrinth channels. A Particle Tracking Velocimetry was used to snap the videos for some bubbles at five consecutive positions along the labyrinth channel under the inlet pressure of 0.02, 0.06, and 0.10MPa. Two half units were selected to capture the images along the labyrinth channel (labeled U and D), in order to determine the influence of buoyancy and gravity on the bubble behavior. A total of 10 observation windows were distributed on the labyrinth channel. The behavior characteristics of micro-bubbles were determined to clarify the influence of inlet pressure on the number, diameter distribution, average motion time, and average velocity of micro-bubbles in the labyrinth channel. The results show that the number of bubbles decreased continuously, and the rate of descent slowly decreased from the head to the end of the channel. There was no significant difference among the three inlet pressures at the end of the flow path. The proportion of bubbles with the larger diameter increased significantly, where the maximum and average diameter of micro-bubbles increased along the channel. The maximum bubble diameter appeared at the end of the channel, and then decreased with the increase of inlet pressure. The distribution range of velocity and trace length decreased at 10 observation positions, with the increase of bubble diameter. However, there was no significant change in the average speed and duration of bubble clusters during the shot section. The inlet pressure posed a great influence on the movement characteristics of bubbles in the channel. The number and the maximum diameter of bubbles decreased, as the inlet pressure increased. The average time of bubble swarm passed the channel of the shooting section was shortened, whereas, the average speed increased at the same position of the labyrinth channel. The bubbles with the higher velocity presented a shorter trace, whereas, those with the lower velocity was a longer trace for all the bubbles in the labyrinth channel under three inlet pressures. But, the maximum trace length and velocity of the bubble increased with the increase of inlet pressure. The inlet pressure was provided the minimum velocity (called the "base velocity") for the bubble swarm to pass through the labyrinth channel. The basic velocity increased, as the inlet pressure increased. Even if the traces of some bubbles were very long, the velocity was higher than the base velocity. Therefore, more gas was dissolved in water under the higher inlet pressure, while the undissolved gas presented in the form of micro-bubbles with a smaller diameter and faster speed. As such, better water vapor transportation was achieved in the system. Consequently, the inlet pressure can be as high as possible within 0.10 MPa during micro-nano drip irrigation, in order to effectively improve the uniformity of water and gas transportation for better aeration performance. Besides, there was no significant difference in the behavior characteristics of micro-bubbles at the two half units up and down connected along the labyrinth channel, indicating the very small influence of buoyancy and gravity on the bubble. The finding can provide theoretical support to improve the uniform aeration drip irrigation and gas transportation during operation in the micro-nano aeration drip irrigation system. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Vegetation has become the main producer to serve as an integral part of natural ecosystem, as well as perform various vital ecological functions. Vegetation coverage has some direct effects on the structure, functions, and health of an ecosystem. The vegetation coverage can also be one of the key ecological parameters that can reflect the level and quality of an ecosystem, particularly on Xinjiang, China, characterized by shortage of water resources and fragile ecological environment in the arid hinterland of Eurasia. New challenge has posed on the ecological system in Xinjiang, as "the Belt and Road" initiative is being promoted. Furthermore, the area and quality of vegetation coverage is degrading, as adverse effects increased from the climate change and human activities in the last 20 years, leading to severe negative impacts on the ecological environment and social economy. Therefore, it is necessary to carry out the long-term sequence monitoring on the vegetation coverage at the regional scale, in order to promote the eco-friendly development model, and further to ensure the sustainable development of the "Silk Road of Green Development". In this study, MODIS/EVI data was employed to obtain the Fractional Vegetation Coverage (FVC) based on pixel dichotomy, thereby to explore the change in vegetation coverage and its driving mechanisms. The variation of FVC was revealed using the percentage of deviation from normal and linear regression analysis. The driving mechanism of FVC change was also analyzed by the gravity center model and correlation analysis. The results showed that: 1) The average vegetation coverage was 0.255 in Xinjiang from 2000 to 2019, where the area with an very low coverage accounting for 63.53%. The vegetation coverage was higher in Yili River Valley, where the area with an extremely high coverage accounting for 77.9%, whereas that in southern Xinjiang only accounted for 6.94%. 2) The FVC was on the rise in Xinjiang as a whole, with a stable variation. The percentage of abnormal change was within the normal range. However, the fluctuation of FVC was relatively large in eastern Xinjiang. In 2015, the FVC value was nearly 20% higher than the average level, with other regions fluctuating in the range of ±5%. The reduction area of vegetation coverage was larger than that of the increasing area, where 53.04% of the area tended to decrease. At the level of significance less than 0.05, the area with increasing trend was large. 3) In the driving mechanisms for the variation of vegetation coverage, the spatial position of vegetation centers, temperature and precipitation were calculated to analyze the change and relationship between the gravity centers of various elements from the spatial level. The vegetation center of gravity fluctuated to high longitude and high latitude. In terms of longitude change, temperature was the main driving factor of vegetation spatial change in Xinjiang, indicating a positive correlation between the center of vegetation and temperature. There was a negative correlation between the vegetation center and precipitation center in Yili River Valley, with R value of -0.492. However, there was no significant relationship between the vegetation center and the center of temperature and precipitation in eastern Xinjiang. The significant change of vegetation coverage was less than 0.05 under the level of low vegetation coverage and uneven distribution. The increased area was greater than the reduced area, indicating an obvious effect of ecological restoration. A recommendation can be to strengthen the vegetation protection, especially in the area of reduced vegetation coverage. The evaluation of vegetation change and its driving mechanisms in different regions of Xinjiang can provide a scientific basis to protect the fragile ecological environment. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With rapid development in economy in China the demand for tourism has been changed exerting pressure on tourism resorts to transform and upgrade. As tourism area bears the responsibility of sustaining social and economic development, its land use has to be diversified, leading to a potential land use conflicts. However, there is a paucity of study on that and we attempt to address this knowledge gap. Assuming that a tourism resort should at least have ecological function, productivity and suitability for living (ecological-production-living suitability), we proposed an empirical model to identify and diagnose potential land use conflicts in tourism resorts by taking Wuyishan National Tourism Resort as an example. The potential land use conflict in resort was divided into five zones with different conflicting levels: zone without conflict, zone with mild conflict zone, zone with moderate conflict, zone with intense conflict, and zone with severe conflict. The conflict was divided into four levels: stable and controllable, quite controllable, slightly out of control, uncontrollable. Preliminary studies showed that there were significant differences in ecological-production-living suitability of the land use in this region, revealing existence of competitions and conflicts in land use. The results showed that the areas with land use conflict ranging from controllable to uncontrollable accounted for 17.76%, 35.59%, 22.37%, 23.74% and 0.55% of the whole area. The stable and controllable zone was mainly in the western, southeastern and central regions, and areas in the high-end health resort area, pastoral health resort area and eco-recreational area. The quite controllable zone was mainly in the transition zone from human production areas to the life and ecological protection area, including the waterfront recreation area and eco-recreational areas. The basic out-of-control conflicts were mainly distributed in the intensive activities of human production and life, which had both constructive and destructive conflicts. The serious out-of-control conflicts were smaller in area but deeper in degree. The spatial distribution, expression and conflict degree of potential land use conflict areas determined the conflict governance strategies should also be different. For example, strategies such as spatial control, quality improvement, and functional manifestation could be adopted according to local conditions. The framework of identification and governance of potential land use conflicts in tourist resorts proposed in this paper can accurately reflect the actual pattern of land use conflicts and can provide reference for the land use planning and management in tourist resorts. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Mung bean is one of the widely cultivated crops in China, and its yield and exports account were the first in the world. However dehulling technology and operation quality of mung bean have not been significantly improved over the long term due to insufficient attention. The poor qualified dehulling rate and dehulled mung beans rate restricted the development of mung bean industry. The unreasonable working parameters (speed of dehulling roller, speed of sand drum, operation time) of the dehuller were the main reason of this problem, which had a negative impact on operation quality. In this experiment, quadratic orthogonal rotation and response surface method were used to obtain the best operation quality, and key working parameters were optimized using Design-Expert. The properties of tested mung beans were analyzed, and the results showed that the color of the mung beans was dark green. With the moisture content of the mung bean at 9.2%, the thousand seeds weight was 63.5 g, and the length, width, thickness were about 5.70, 4.18, 4.33 mm respectively, the repose angle of mung beans was 23.71°, the crushing force of 60% mung beans was about 36 N. The data analysis of the dehulling experiment showed that primary and secondary factors for qualified dehulling rate was speed of dehulling roller > operation time > speeds of sand drum. Regarding to the dehulled mung beans rate, the order was: operation time> speed of dehulling roller > speeds of sand drum. The result of interaction analysis showed that the interaction between speed of dehulling roller and operation time had a significant impact on the qualified dehulling rate, while the interactions between other parameters were not significant. The interaction between speed of dehulling roller and operation time had a significant effect on dehulled mung beans rate, and the interaction between the speed of the sand drum and operation time also had a significant effect on dehulled mung beans rate. The optimal working parameters of dehuller for dried mung beans were speed of dehulling roller of 25.20 r/min, speed of sand drum of 1642.61 r/min, and operation time of 108.8 min. With the optimal working parameters, qualified dehulling rate and dehulled mung beans rate of the dehuller were 99.72% and 86.57%, respectively. The results of verification test and optimization result were highly consistent. Production tests were carried out 20 times in the factory according to the optimization results. With the optimal parameters applied by dehuller for dried mung beans, qualified dehulling rate and dehulled mung beans rate were 99.3% and 85.6%, respectively. The results of the production verifications were very close to the results got from the previous model results, and the quality of the dehuller improved greatly. This study is helpful for the improvement of the dehuller for dried mung beans. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to improve the shelling rate and reduce the breakage rate, the central composite experiments were conducted to optimize the working parameters. Firstly, the physical properties of coix lacryma-jobi were studied, and the study object was “White shell coix lacryma-jobi” planted widely in Guizhou Province, the shape of which was irregular, and the thousand kernel weight was 86.5g. Proportion of thickness δ≤5 mm was 25%, 5＜δ≤5.5 was 58%, and others were δ＞5.5. The weight ratio of shell and kernel was 1:2.5. The moisture content of shell and kernel was 11.6% and 12.7% respectively. The crushing force of coix lacryma-jobi was 45 N≤F≤95 N, 60% of which was about 65 N. The flow angle of coix lacryma-jobi tested by inclined surface device was 14.5°. Based on composite experiment methods of quadratic orthogonal rotation, the effects of key components’ main working parameters of coix lacryma-jobi sheller on shelling rate and breakage rate were analyzed, the parameters include rotation speed of rotary plate, distance between rotary and stationary plate, working face width of stationary plate, and the data were analyzed based on the Design-Expert software. The mathematical regression models of shelling rate and breakage rate were built, and corresponding variance analysis were conducted. A regression equation of the relationship between variation coefficient of 3 main working parameters was obtained. Through the analysis of variance, the results showed that the most influential factor for shelling rate was the rotation speed of rotary plate, and the minimum impact factor was the distance between rotary and stationary plate; regarding to the breakage rate, the most influential factor was working face width of stationary plate, and the minimum impact factor was the rotation speed of rotary plate. The response surface method was utilized to analyze the effects of factors’ interaction on shelling rate and breakage rate, and the multi-objective optimizations were conducted for the regression models to obtain the working parameters for the best shelling rate and the lowest breakage rate. The optimal combination working parameters of key components of coix lacryma-jobi sheller were the speed of rotary plate was 1 099.15 r/min, the distance between rotary and stationary plate is 4.91 mm, and the working face width of stationary plate of 7.63 mm. Under the condition of the optimal combination working parameters, the shelling rate and breakage rate was 50.49% and 3.02%, respectively. The production verification test was conducted in factory. With the optimal parameters of coix lacryma-jobi sheller, the shelling rate was improved greatly, and the shelling rate and breakage rate was 51.1% and 3.6%, respectively, which close to the results obtained from the previous model. The study provides the scientific basis for key components’ working parameters optimization of coix lacryma-jobi sheller. [ABSTRACT FROM AUTHOR]

Aiming at the phenomenon of excess nitrogen (N) application rate in winter wheat field in North China Plain, measuring and modelling photosynthetic rates under different N rates is helpful to understand the physiological basis of the influence of reducing traditional N application rates on crop yield. This study set up 3 amounts of N rates, i.e. 290, 190 and 110 kg/hm2, as high (N3), middle (N2) and low N (N1) treatments, respectively in drip irrigation winter wheat field in 2 consecutive growing seasons (2012-2014). The coupled model of photosynthesis and stomatal conductance was established to model photosynthetic rates. Photosynthetic rates to intercellular CO2 concentration response curves (An-Ci curves) were measured in 2014 to determine key parameters of the model from the heading stage to harvest stage. Daily dynamics of photosynthetic rates were measured in 2013 as the verification data of the coupled model. The results showed that the apparent maximum carboxylation rate of Rubisco (Vcmax) and maximum electron transfer rate (Jmax) was significantly affected by N treatments. The measured Vcmax varied from 84.5 to 153.3 μmol/(m2·s) and Jmax varied from 156.5 to 236.2 μmol/(m2·s) during the measurements and among treatments. Differences of Vcmax and Jmax among treatments were more significant when the measurement dates close to the harvest stage. During the filling stage (May 21st to 23rd), only Vcmax and Jmax of the low N treatment (N1) was significantly lower than that of high N treatment (N3), the corresponding values of the middle N treatment (N2) were not significant lower than those of N3. During the milking stage (June 2nd to 3rd), however, the Vcmax and Jmax of both N2 and N1 were significantly lower than those of N3. There was no significant difference in the ratio of Jmax/Vcmax among treatments during the three measurements. The ratio of Jmax/Vcmax gradually increased along with the advancing of growing stages and changed from 1.49 to 2.00 during the measurements. The differences of Vcmax among treatments could be quantified by leaf mass N content. Then the Jmax value can be calculated according to the ratio of Jmax/Vcmax. The slope (g1) and intercept (g0) of the stomatal conductance sub-model were changed with different N application. During the filling stage (May 21st to 23rd), it was found that the N3 treatment with the highest g0 and the smallest g1. The analytical solution of the photosynthesis model and the Ball-Berry stomatal conductance model was derived to solve the coupled model. Considering the difference between the key parameters, the simulation results of the coupling model for photosynthetic rate from the daily process was good, with the average absolute error were 2.11 and 2.23 μmol/(m2·s) for the 2 measurements in 2013 and the differences between simulated and measured photosynthetic rate were less than 5%. The prediction of the model also showed that different parameters have different effects on the simulation results of photosynthetic rate. For example, although the g0 of stomatal conductance sub-model is often relatively small, it will cause large error in the simulation of photosynthetic rate under low light intensity, while some researchers may neglect this parameter when running the model. The model can be used to simulate photosynthetic rates under change of single physiological or environmental factor and change of multi factors, so as to better predict the yield changes. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Diesel engines are widely applied in the field of transportation and manufacturing because of its better power and fuel economic performances. However, diesel engine emits huge quantities of particulate matter (PM) which pose a great threat to the human health and environment. As emission regulations are becoming gradually stricter, it is imperative to stringently control diesel PM emission with a feasible after-treatment technic. Diesel particulate filter (DPF) is considered as the most effective mean to reduce diesel PM emission. The core of DPF regeneration is the control of upstream temperature of DPF. DPF regeneration is mainly divided into active and passive regeneration, the regeneration temperature is mainly controlled by the air management and injection strategy for the active regeneration. Air management is mainly by changing the intake throttle valve to control the intake air flow, and then controlling the exhaust temperature, which is important to match and improve the low temperature performance of the after treatment system, but the change of intake air flow will inevitably affect performances of the engine. So the control strategy of air management needs to be studied in depth. In order to obtain the intake throttling control strategy based on DPF active regeneration temperature under the whole working area of diesel engine, three typical working conditions were designed, including low-speed light load (working condition A:1 250 r/min 25% load), middle-speed medium load (working condition B: 2 000 r/min 40% load) and high-speed heavy load (working condition C: 3 000 r/min 70% load), and the effects of intake throttle opening on pumping loss, exhaust thermal condition, in-cylinder combustion and emission characteristics of diesel engine were studied. The experimental results showed that the throttle effect was enhanced, the air intake flow gradually reduced under the different working conditions with the increasing of the throttle valve opening, which lead to the deterioration of combustion in cylinder, the decrease of the maximum combustion pressure, the increase of the BSFC, CO, NOX and smoke emissions. However, the decrease of the intake air flow delayed the start timing of combustion, prolonged the ignition delay period and increased the combustion temperature as well as the exhaust temperature, which inhibited the generation of HC effectively. When the intake throttle valve opening was reduced to 20%, the reduction rate of air intake flow was greater under the low-speed light load condition, the increase rate of exhaust temperature was more significant as much as 63%, while under the heavy load conditions, the exhaust temperature was slightly increased, but the pumping loss was increased by up to 19.2%, which seriously deteriorate the fuel economic performance. Based on the experimental results, the intake throttle valve opening was set respectively 35%-45%, 50%-60% and 70%-80% range according to the increasing potential for the exhaust temperature and performance deterioration under working conditions A, B, C in this paper. Moreover, the intake throttling strategy was given within the scope of all working conditions based on exhaust temperature distribution of the engine that light loads adopted the larger intake throttle valve opening, with the increasing of load, the throttle valve opening was gradually increased to the full open state. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Field weeds have a great effect on the yield of normal economic crops. The commonly used methods of weeding include artificial weeding, mechanical weeding, weed quarantine, biological control, chemical control, and so on. Among those methods, chemical weeding is the best when it comes to sudden grass damage (the weeds of disaster break out suddenly), because it works well and takes less time. However, when we use chemical weeding, there are many problems such as low utilization rate of liquid medicine and serious pollution to the environment with overplus liquid. Therefore, toward-target pesticide application is proposed to solve these problems above all. As we all know, toward-target pesticide application machineries often use machine vision technology to obtain spatial location information of weeds, which makes the nozzle rigidly fixed on the machine and at the same time, the control system adjusts the valve to open and close to achieve the purpose of spraying. On this basis, we use spraying nozzle to change the direction of application, resulting in precision spraying in this paper. In order to study the law of motion for spray droplet, we established dynamic model based on application methods with the principle of aerodynamics, and then the formula of the droplet flying and the analytic formula of the falling point were deduced. Next, the numerical simulation analysis of the covering area was carried out. Especially, in the process of analysis, we discussed the resistance characteristics of spray droplets, the nozzle angle, nozzle speed, machine speed and injection pressure, which affect the movement process we discussed. What's more, the model established above can also be used to control the location and shape of the droplet cover area by adjusting the working parameters, to improve the accuracy of toward-target pesticide application. Furthermore, in order to verify the correctness of the model, we set up the toward-target pesticide application platform and selected the special test site. Under no wind conditions, we conducted a simple target spraying test indoor, and then measured the geometric characteristics of actual liquid dripping place carefully. At the same time, the relevant parameters were obtained by high-speed camera technology. Next, we took the data into the dynamic model mentioned above to get the theoretical coverage of the liquid medicine, which was then compared with the actual coverage of the liquid medicine. Finally, it can be found that there is an error between the calculated and experimental results, and the error range is 8%-13%. In addition, to study the sedimentary characteristics of liquid medicine with this application method, we analysed the distribution law of the deposition amount of liquid medicine in the effective coverage area by water absorption paper weighing method. According to the analysis, it can be seen that the peak value of sediment changes regularly with the parameters such as the change of the nozzle angle, which suggests that the physical background of the model is clear, and the correlation between the parameters of the model and the sprinkler type is small, so the model transplant is strong. In other words, it can be used as a theoretical basis for the relevant spraying machinery. [ABSTRACT FROM AUTHOR]

Determining the photosynthetic parameters is the basis for understanding the physiological causes of water saving and yield increasing under drip irrigation modes. In this study, intrinsic photosynthetic parameters were determined during four years experiments in winter wheat field treated with six drip irrigation modes (T1 to T6, stands for treatments of lower irrigation amount with straw mulch, lower irrigation amount without straw mulch, moderate irrigation amount with straw mulch, moderate irrigation amount without straw mulch, higher irrigation amount with straw mulch, and higher irrigation amount without straw mulch, respectively). The differences in photosynthetic parameters among treatments were statistically analyzed, and the correlations between photosynthetic parameters and crop yield were analyzed. The results showed that increasing irrigation amount and straw mulch enhanced the apparent photon quantum efficiency (α), photosynthetic capacity (Amax), maximum carboxylation rate (Vcmax) and maximum electron transfer rate (Jmax), respectively. However, the interaction effects of irrigation amount and mulching on photosynthetic parameters were not significant (p > 0.1). The effect of drip irrigation on apparent quantum efficiency (α) was significant (P < 0.05) during the late periods of the heading and grain filling stages, while the effect of straw mulch on α was not significant (P > 0.1). The effect of straw mulch and drip irrigation on Amax show significant (P < 0.05) seasonal differences. The effects of drip irrigation on Vcmax and Jmax were significant (P < 0.05) during the mid-season periods of the heading and grain filling stages, while the effects of straw mulch were significant (P < 0.05) during the later periods of the heading and grain filling stages. The results of multiple comparisons showed that the photosynthetic parameters of T5 were the highest (P < 0.05). Except for the measurements in 2016, the corresponding values of T6 and T3 were slightly lower but with no significant difference from those of T5 (P > 0.1). However, the corresponding values of T2 were significantly lower (P < 0.05) than those of T5. These results suggested that, under higher irrigation amount, photosynthetic parameters were not affected significantly (P > 0.05) by mulching, but under lower irrigation amount, the parameters significantly (P < 0.05) decreased if treated with no mulching. The average values of Amax during the four years from T1 to T6 were 29.59, 26.45, 31.44, 28.68, 32.42 and 30.90 μmol/ (m2·s), respectively. The average values of Vcmax during the four years from T1 to T6 were 121.42, 107.68, 133.42, 113.55, 141.83 and 129.95 μmol/ (m2·s), respectively. From the point of view of reducing the amount of irrigation, T3 irrigation scheduling can be used as an optimal strategy for winter wheat under drip irrigation with straw mulch, indicating that 65% to 85% of the field capacity was used as the lower and upper limits of soil moisture control. The management practices of drip irrigation with straw mulch can keep the higher photosynthetic capacity of flag leaf for winter wheat. The differences in Amax and Vcmax among treatments could be explained by the leaf nitrogen content (Nmass). Grain yield for all years were also linearly related to Amax and Vcmax, respectively. Therefore, by measuring Nmass, one can estimate Amax and Vcmax, thus achieving the yield estimates of winter wheat field in this area. In addition, the photosynthetic characteristic parameters can also be applied to the crop model to improve the accuracy of model prediction under different water and mulch regimes. [ABSTRACT FROM AUTHOR]

In order to improve both poor coating qualified rate and high breakage rate of peanut seeds caused by unreasonable working parameters of rotary table-roller coating equipment, the single factor and central composite experiments were conducted. The effects of the main working parameters, including ratio of seeds weight to coating volume, dilution ratio of seed coating, speed of roller, on coating qualified rate and breakage rate of peanuts coating were analyzed by means of the rotary table-roller coating test rig. The study object was “Huayu 33”, which was 16.22-19.16 mm in length, 8.06-10.36 mm in width, and 7.16-8.36 mm in thickness and whose moisture was 11.6%, and thousand kernel weight was 812.1 g. The single factor experiments were firstly conducted, and the results showed the influence laws of the 3 main working parameters on coating qualified rate and breakage rate, which were necessary to determine zero level of each parameter in the quadratic regression revolution design. And then the composite experiment methods of quadratic orthogonal rotation were adopted, the data were analyzed based on the Design-Expert software, the mathematical regression models of peanuts coating rate and breakage rate were built, and their corresponding variance analysis were conducted too. A regression equation of the relationship between variation coefficient of the 3 main working parameters was obtained. Through the analysis of variance, the results showed that the most influential factor for the coating qualified rate was the ratio of seeds weight to coating volume, and the minimum impact factor was the dilution ratio of seed coating; regarding to the breakage rate, the most influential factor was the speed of roller, and the minimum impact factor was the ratio of seeds weight to coating volume. The response surface method was utilized to analyze the effects of factors’ interaction on the coating qualified rate and breakage rate, and the multi-objective optimizations were conducted for the regression models. The optimal combination working parameters of the drum coating test rig were the roller speed of 18.34 r/min, the ratio of seeds weight to coating volume of 31.73 g/mL, and the dilution ratio of seed coating of 4.76. All of those were obtained by the optimization solution of all factors with the quadratic regression model equation of performance evaluation indices in the range of experimental parameters constraints. Under the condition of the optimal combination working parameters, the coating qualified rate and the breakage rate were 97.35% and 0.37%, respectively. This coating quality met the need of peanut seeds processing industry. The results of verification test were consistent with those of optimization solution. Production verification test was conducted with the 5BY-500-J coating machine (the productivity was 5 t/h when it was used for corn seeds coating operation) in Nanjing Agricultural Machinery Factory. The coating machine worked the same as the rotary table-roller coating test rig, but the working parameters were not reasonable for peanut coating. In the experiment, the working parameters of 5BY-500-J coating machine were adjusted according the optimization results by variable frequency regulation of the drum and the control of feeding parts of seeds coating. With the optimal parameters applied by the coating machine, the coating quality was improved greatly, and the coating qualified rate and breakage rate were 97.05% and 0.40%, respectively, which were very close to those obtained from the previous model results. The results of verification showed that the coating machine could be used for peanut seeds processing after working parameters optimization. The study provides the scientific basis for the working parameter optimization of rotary table-roller coating machine for peanut seeds. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Understanding of evapotranspiration (ET) of crops is very important for the research on the balance of water, such as hydrology, agronomy and environmental science. The Penman-Monteith equation (PM equation) has been widely used for predicting the actual ET, but the direct application of the PM equation is very difficult because of the determination of canopy resistance. Two operational models are developed to determine the actual ET based on the PM equation: FAO-PM model (FAO is the abbreviation of Food and Agriculture Organization) and Rana and Katerji model (R-K model). To analyze the applicability and stability of these 2 models on predicting the ET from winter wheat field in the North China Plain, the dynamic variations of ET from winter wheat field in 2013-2014 and 2014-2015 were studied on the basis of the data obtained with eddy covariance system (EC) and microclimate observations. The applicability of the R-K model was also analyzed in the experimental field. The R-K model was calibrated and validated with the data obtained in winter wheat growing seasons during 2013-2014 and 2014-2015. The daily ET predicted by the R-K model and the FAO-PM model was compared to the observed ET with the EC method. The application of the R-K model in predicting the ET in different growing stages of winter wheat was further studied. Results indicated that the ET of winter wheat showed obvious seasonal variation, and the minimum daily ET occurred in late January (the value was nearly zero). With the advent of the returning green stage, the winter wheat entered the development stage, and the ET started to increase slowly, reaching the maximum that was 7.37 mm in May for 2013-2014 and 5.72 mm in April for 2014-2015. The minimum monthly ET occurred in January, which was 10.7 and 8.6 mm in 2013-2014 and 2014-2015, respectively; and the maximum monthly ET was 142.8 and 102.5 mm in May for 2013-2014 and 2014-2015, respectively. The total ET of whole growing season was 436.3 and 334.8 mm respectively for these 2 growing seasons. The coefficients a and b in the R-K model were calibrated by using 3 data sets (data in 2013-2014, data in 2014-2015, and data in both years). There was small difference between the 3 data sets, and the stability of the R-K model was good. The calibrated coefficients a and b by using the data in 2013-2014 were 1.277 and 0.540 respectively (R2=0.741 and RMSE=2.034×10-5) and taken as the calibrated coefficients suitable for the experiment field. The data in 2014-2015 were used to validate the performance of the model. In the FAO-PM model, the slope of the linear regression between the observed and predicted values (1.01) was slightly greater than 1.0, the coefficient of determination was higher than 0.85, the index of agreement was 0.90, and the relative error was 16.2%. In the revised R-K model, the slope of linear regression (0.89) was less than 1.0, the coefficient of determination was higher than 0.85, the index of agreement was 0.91 and the relative error was 6.95%. These statistical parameters indicated that predicting daily ET with the revised R-K model performed slightly better than the FAO-PM model. To guide the management of the field irrigation, the ET during different growing stages was predicted with the R-K model. The performance of the model was much better in late-season stage with the relative error less than 0.5%, followed by the development stage with the relative error of about 19%, and then the mid-season stage with the relative error of about 21%, and poor for the initial stage and the overwintering stage with the relative error value of about 48% and 92%, respectively. The sensitivity analysis indicated the R-K model had good stability because it was only slightly sensitive to the aerodynamic resistance and the critical resistance. Overall, the R-K model is a promising model to predict the actual ET, and the calibration and validation of the model need further study at hourly, daily, monthly and annual time scales in different locations. [ABSTRACT FROM AUTHOR]