Abstract:As harvesting operation is with the most labor cost, however, the most difficult to realize mechanized work in greenhouse crop production, robotic harvesting technology has been developing rapidly in recent decades. Especially, research on robotic harvesting technology for main crops such as tomatoes, strawberries has been conducted continuously and deeply in Japan. Since the beginning of the new century, research in China in this field has become the most active. Development process of research on robotic harvesting technology for different greenhouse crops in Japan, China, the European Union, South Korea and so on were analyzed, and global main research units and specialists, key technical characteristics, level of development and course of evolution in this field were summarized. In conclusion, the flexibility to complex non-structural environment and deep integration of complex robot system were regarded as two keys to stimulate the development of greenhouse picking robot technology. Finally, it was believed that operation environment factorization, robot configuration standardization, multi-robot cooperation and man-robot collaboration would become the development trend in future, thereby to accelerate the development of robotic harvesting technology and its application in greenhouse industry.

Abstract:In the process of automatic maize kernel trait extraction, the parameters of maize kernel can be obtained by machine vision. In the process of machine vision analysis, the accumulation of maize grain affects the extraction of kernel parameters. A method of obtaining information of corn kernel and cyclotron vibration platform was designed. Through the analysis of the stress distribution of accumulation seed cyclotron motion process, the vibration platform swing speed was determined, and the grain accumulation was reduced. Through the vibration kernel accumulation was reduced first, and then maize kernel image was obtained. In the image processing and analysis stage, image of maize kernels was segmented. To solve the segmentation problem of maize kernels, an improved watershed algorithm was proposed. After watershed segmentation, the D-value between the minimum watershed value and the minimum value of the pixel points between adjacent segmentation region were calculated, and then the D-value was compared with T. If the D-value was less than T, the adjacent segmentation region was merged. Segmentation made each maize kernel be a region. The number of maize grains corresponded to the number of regions. After the segmentation was completed, minimum external rectangle of single seed was established by improved Graham scanning method. The length and width of the minimum external rectangle corresponded to the length and width of the kernel. Verification experiments were carried out on the corn seed metering device. The final test results showed that the correct rate of segmentation method proposed on maize grain reached above 98.05% and the determination correlation coefficient between algorithm and manual measured values was above 0.97. The system can realize rapid acquisition of relevant information of maize kernel, and achieve the expected performance index as well as meet practical demands.

Abstract:In view of the difficulty in region location and classification of potato typical diseases under natural conditions, a new adaptive features fusion and fast recognition method of potato typical disease images was proposed. The segmented disease image, processing object of the proposed method, could be obtained as following two steps. Firstly, by using K-means, Hough transform and superpixels segmentation algorithms, the whole potato blade containing disease region was located in complicated background. Secondly, the disease region was separated from green blade by combining with two-dimensional Otsu and morphology method. On the basis of the segmented disease image, totally 124 potato disease features, including 18 color features, 21 shape features and 85 texture features were extracted. As thus, the color, shape and texture features were fused adaptively based on principal component analysis (PCA) algorithm and weighted formulation, and used to potato diseases recognition by support vector machine (SVM). According to features fusion and SVM recognition, totally 13 weighted principal components were gained as following three steps. Firstly, color, shape and texture features were automatically divided into many feature blocks, including RGB and HSV, geometric statistics (GS), central moments and Hu moments, Gray-level co-occurrence matrix (GLCM), high frequency low order moments and low frequency low order moments (HMLM), and high frequency covariance matrix eigenvalues and low frequency lower order moments (HELM). By comparison of recognition rates and features dimension, RGB, GS and HELM feature blocks were selected from color, shape, texture feature blocks, respectively. Secondly, five RGB, five GS and three HELM principal components were acquired by PCA algorithm. Thirdly, RGB, GS and HELM were weighted based on their recognition rates of principal components, and each principal component was also weighted based on weight distribution formulation. The recognition test of three kinds of typical potato samples showed that the proposed method had an obvious advantage. By using the same SVM recognition model, and compared with recognition rates of traditional adaptive methods, including PCA descending dimension, feature sorting selection, and so on, the proposed adaptive feature fusion algorithm had high average recognition rate which was increased by at least 1.8 percentage points. By using the same 13 adaptive fusion features, average recognition rate of the proposed recognition method was 95.2%, which were increased by 3.8 percentage points and 8.5 percentage points than those of ANN and Bayes, respectively, and run time of the proposed recognition method was 0.600s, which was 3s faster than that of ANN. Therefore, the proposed method could be used to greatly improve the recognition speed based on effectively ensuring the recognition accuracy.

Abstract:Considering the soil of in mid-lower Yangtze River is sticky and the amount of straw is large, the furrow should be ditched while rapeseed is planting, which leads the power consumption of traditional tillage is large. Compared with the traditional plow, driven disc plows are not easy to be blocked and traction resistance is small. The design of symmetrical type driven disc plows combined tillage machine for rice-rapeseed rotation area was carried out. According to dynamics and kinematic analysis of driven type disc plows, its main structure and technical parameters were analyzed and determined. Based on the principle of plow forming and soil extrusion, the surface of front ditch plow was designed, and it was determined that when the width of ditching area was 350mm, the quality of furrow and seedbed can be ensured. The tillage depth stability experiments results indicated that actual working depth of the machine was consistent with the control depth, and tillage stability coefficients were more than 90%. The seedbed quality experiments results showed that the depth and width of furrows which was ditched by ditching system were 241.6~293.5mm and 328.6~370.8mm, respectively. The soil squeezed by combined ship type opener can effectively filled the furrows which was formed by driven disc plows, the actual landfill rate of furrows was more than 87.67%. The seedbed roughness was 22.45~26.70mm，soil crushing rate was 60.14%~68.37%. The orthogonal test indicated that the optimum operation condition was the tillage depth was 180mm, the speed of machine was 3.5km/h, and operating speed of driven disc plows was 160r/min. Under this condition, the power consumption was 24.37kW, straw coverage rate was 92.78%, soil crushing rate was 66.74%, seedbed roughness was 24.18mm, and landfill rate was 92.3%. The experiment results showed that the quality of symmetrical type driven disc plows combined tillage machine satisfied the actual production requirements of rapeseed planting. The research conclusion had great theoretical value and practical significance to the design of machine which worked for planting rapeseed.

Abstract:With the improvement of agricultural mechanization in China, the development of agricultural machinery suitable for hilly and mountainous regions has been paid more and more attention；However, due to poor hilly and mountainous regions operating environment, when agricultural vehicles are in the walk, the processes of roll angle and pitch angle have a great change, affecting vehicle stability. The existing agricultural vehicle leveling is mainly through mechanical, electronic, hydraulic and other control technology to achieve, mostly when the body tilts, according to the degree of tilt of the vehicle to calculate the amount of adjustment and leveling, this method is characterized by complex control and high cost. Aiming at the problems, an adaptive leveling method was proposed. And an adaptive leveling suspension and an adaptive leveling chassis with the suspension were designed by using this method. Three-dimensional model was established by using 3D modeling software, and the model was introduced into dynamic analysis software ADAMS for simulation analysis. By analyzing the simulation process, it was possible that the sum of the roll angle and pitch angle of the adaptive leveling chassis can be reduced by about 60% when walking on amplitude and wavelength-specific waveform ground which referenced to a certain operating environment. The test of sample machine was carried out, and the results showed the feasibility of the adaptive leveling method and the correctness of the simulation analysis, that was, the adaptive leveling of the chassis can reduce the sum of roll angle and pitch angle when the chassis was running and can be realized and met the requirements of the agricultural chassis in the hilly area.

Abstract:A clamping static and dynamic finger-spoon maize precision seed metering device was designed based on limited guiding principle to improve the performance and adaptability of maize seed metering device and meet the requirements of precision planting. The overall structure and working principle of the seed metering device were illustrated and analyzed. The optimal design of structural parameters of key components was conducted, such as the finger-spoon plate and the limited guiding assembly. The single factor tests were carried out with rotational speed and adjustment dimension as the experiment factors. The average seeding qualified index and the seeding coefficient of variation were chosen for evaluating the seeding performance. The results showed that the clamping finger-spoon maize precision seed metering device had good adaptability to four different types of maize seeds. To improve the working performance of the metering device and obtain the best operation parameters, the quadratic general rotary unitized design was carried out. Based on experimental data, a mathematical model was built by using the Design-Expert 6.0.10 software, the experimental factors were optimized, and the best combination was achieved. Test results showed that as the rotational speed was 30.5r/min, the adjustment dimension was 12.0mm, and the seeding qualified index was 88.41%, the seeding coefficient of variation was 12.32%, which could meet the requirements of precision planting. The results can provide the guidance and direction for the design and development of high-speed precision mechanical seed-metering device.

Abstract:Xinjiang is the largest production base of quality cotton and commodity cotton in China. Sowing is one of the most important links which affects the development of cotton industry. In order to improve the precision and efficiency of seed-metering device for cotton, a pneumatic cylinder array precision metering device for cotton was designed, which combined the features of array suction and pneumatic clearing with side direction. The working principle and component of precision seeder were introduced, the key structure parameters were determined, and the mechanical model of single cotton seed during the air-suction filling process was established. In test, cotton seed Xinluzao 48 was selected as experimental material. Based on pre-experiments, the cylinder speed, hole diameter and vacuum pressure were taken as main impact factors, the quality of feed index, miss index and multiple index were taken as response indices, and the second orthogonal rotation combination test was executed, which used the Design-Expert software. The regression models were established, and effects of various factors on the performance indices were analyzed. The research gained the best combination of the parameters by using multi-objective optimization, which was as follows: the cylinder speed was 15.5r/min, the hole diameter was 3.5mm, and vacuum pressure was 4.2kPa. Under the condition of the optimal combination parameters, the quality of feed index, miss index and multiple index were 93.5%, 2.0% and 4.5%, respectively. According to optimization parameter combination, the verification test was repeated five times, the results showed that the experimental results were basically consistent with the optimization results, and the sowing quality satisfied the requirements of precision sowing for cotton. The sowing adaptability experiment was carried out under the same conditions with three cotton seeds (Xinluzao 48, Xinluzao 52 and Xinluzao 60), whose overall dimension existed some differences from each other. All the qualities of feed index were more than 92%, all the miss indices were less than 3%, and all the multiple indices were less than 5%, indicating that when planting different cotton seeds, the precision seeder had certain adaptability to different varieties of cotton seeds. The study provided a theoretical reference for the design of pneumatic cylinder precision seed-metering device for cotton.

Abstract:Currently, wind speed profilers in common use have many problems, such as complex wiring, large volume, high power consumption, low measurement accuracy and automation level. They are also unable to achieve the real time recording and data processing. These bring many difficulties to study the variation law of near surface wind velocity, terrain roughness and its ability to resist wind erosion of degraded grassland. A thermal wind speed sensor which had small volume, low power consumption, high precision measurement was developed, and a near-surface velocity profiler with functions of automatic wind-direction recognition and wireless data transmission was designed, which can realize data automatic collection, wireless transmission and real-time data processing of environmental temperature, humidity, atmospheric pressure and near-surface wind speeds. Experiment results showed that the rotating start-up wind speed of the profiler was 3.7m/s, and the measurement range of the wind sensor whose maximum response time was no more than 3s was 0~16m/s with accuracy not less than 0.3m/s. It can work continuously more than 7h with one time charge, reflecting the change rule of the near-surface wind speed in height accurately with goodness of fitting of wind speed profiles above 0.9. The system can circularly scan up to six testing points, automatic collect and process wind speed data. The length of data packet was 35 bytes, the effective transmission distance can reach 500m and the data transfer time for six testing points was less than 10s under the conditions of 2.4kb/s transfer rate and maximum transmitting power. The system had advantages of low power consumption, easy to use, simple operation, automatic data acquisition, which can satisfy the needs of studying the change rule of near-surface wind speed.

Abstract:Discrete element modelling (DEM) is a numerical method for examining the dynamic behaviour of granular media. Soil is a nonuniform, discontinuity, elastic-plastic complicated medium. Although there are some advantages of using continuum numerical methods, the assumption of continuity is not always valid, as when there is a change in the soil structure and soil translocation. In order to overcome the shortcomings of the continuum numerical methods, discrete element modelling (DEM), which is a discontinuum numerical method for modelling the mechanical behaviour of granular materials, is a relevant approach for modelling soil as it can consider soil failure, deformation and translocation. In DEM simulation, soil is composed of individual particles which can be defined to be very small in size. And one of the key aspects for successful DEM simulation is to define and calibrate the model soil particles so that they reflect the behavior of real soil. This study presents a systematic method for calibrating a granular soil model, which is based on the surrogate model theory. This systematic method including four steps: (1) construct the soil contact model, the soil parameters were determined by two ways,measurement of three of the real-material properties through experiments and reference some soil parameters;(2) determination of the design variables defining the virtual soil, the design variables were selected by soil parameter sensitivity analysis;(3) construction of surrogate models for the virtual-material properties as a function of the design variables via simulated experiments;(4) optimization of the design-variable values to fit the virtual-soil properties to the real-soil values. The Edinburgh Elasto-Plastic Cohesion Model (ECM) was selected to fit the soil particle contact model, which was the elastic-plastic mechanics model. And the ECM contact parameters and it’s value were constant adhesive pull-off force f0：-0.001N， adhesive parameter stiffness kadh：45kN/m， tangential stiffness factor γt： 0.05，loading spring stiffness k1：100kN/m， unloading/reloading spring stiffness k2：613kN/m. The virtual soil model sensitivity analysis results showed that the particle radium, particle contact static friction and rolling friction should be calibrated and optimized. Finally, this paper constructed a soil model, the real soil sample experiment tested were taken from Zhuozhou city Hebei province, the soil texture is sandy loam soil. By this way, the optimized soil model parameters were particle radium 5.7mm，the static friction between two soil particles 0.45，the rolling friction between two soil particles 0.21, respectively. The soil penetration resistance tests simulation with optimized physical parameters were carried out. The real test about soil penetration resistance were carried out. Results showed that the difference values between virtual simulation and real test within 5.1%. And, it proved that the soil model after optimized could replace the real soil and take some simulation relate to soil-implement. This study provide the theory for soil model parameter calibration and optimization based on DEM method.

Abstract:Annual production of straw is 600 to 800 million tons in China.Dr.LI Shizhong solid-state fermented crushed straw material to acquire ethanol.However, the fermentation heat in bed often over accumulate and kill the yeast,as crushed straw material has low heat conductivity.Dr.Li use rotary drum with straight plates as fermentation drum to solve the problem. The length of plates and the number of plateshasgreat influence on movementand mixing of crushed straw material. However, there is less study in this area. In order to study the influence, section test platform was designed referred to laboratory level rotary drum. The drum can connect 1/2/4 plates andthe length of plates can adjust to 15%/35%/55%/75% ratio of drum (R). The material filling ratio and rotary speed is the same as laboratory level rotary drum: 50%, 1r/min. Some of the material was colored black while the other remains uncolored. They are laid in drum orderly to form acolored and an uncolored material layer.The two layers will mix with drum rotation, and the bed section color will change at the same time. Therefore, the section color can measure the mixing degree of colored and uncolored material. The faster the section color turn uniform grey, the faster thematerial totally mixed. The faster the material totally mixed, the greater the promoting effect of plates on averaging bed’s fermentation heat.The method to measure mixing degree was built based on image analysis, as shown in figure 2.Mesh the bit-mapped picture and calculate the number of uncolored material grids (N0) and all material grids (N) as the black pixeldensity interval between them are different. The quotient (Imix) of N0 divided by N is dimension less and will turn to 0 from 0.5 along with mixing and can mark the mixing degree. The time Imix- time fitting line turn 0 is the complete mixing time of colored and uncolored material (Tc).Data analysis resultshows that: Imix is the most accurate in the case of grid size 8mm;black pixel density [0.1,0.7] marks the uncolored material grid, [0.1,1] marksall material grid. The software to calculate Imix was programmed with Visual Studio. Thirteen section-mixing tests were done: 1/2/4 plate(s) with length 15%/35%/55%/75% ratio of drum.The control group is 0 plate. Each test were done 5 times to obtained the average Tc.The results show that: (1)The length of plates has greater influence on Tc than the number of plates, they are in the same order of magnitude and have strong coupling effects. (2) Tc is the smallest under influence of 4×0.55R plates. (3) Synthetically, Tc change like cos function along with longer plates, change like exponential function along with more plates. (4) Tcdecrease under influence of single long plate or multi middle-length plates, increase under influence of multishort plates or multilong plates. The movement modes of material were studied. From 0 to 4 plates, 0.15R to 0.75R, there is no one unique mode for every test condition. All the movement modes,the influence of plates on mixing and the mixing mechanismhave been analyzed and classified which is shown in table 2.The research can guide designing of plates of laboratory level rotary drums. It can also deepen the understanding of complex movement of crushed straw material in rotary drum with plates. However, for industrial level rotary drums, the conclusions above can not be used uncritically as the drums become much bigger. Tests need to be done on industrial level drums with methods above to acquire conclusions of bigger drums.Furthermore, two important conclusionsfor any kind of mixing process were put forward.(1)There are only two ways to mix material A and B. The first way is to let material group that totally comprised of Aleaves Amaterial layer and embed in B material layer. The second way is to break and mix material group which contains both material A and B. The first can happen in any part of the material bed, while the second can only happen in interface of material A and B. (2) If there is no permanently blocking area, the more material falling areas the material bed has, the faster the colored and uncolored material mix.

Abstract:In order to promote technology progress and innovative development of feed mixers and sustainable development of feed industry in China, carrying out mixing mechanism and innovative research of feed mixers is of great significance. In view of less research of mixing mechanism of feed mixers in China, the mechanism analysis and parameter optimization of the developed blade-type mixer were carried out. Through theoretical analysis and high-speed photograph research, the conclusion could be obtained that the material distribution zone could be divided into peristalsis zone, sliding zone and throwing zone according to the material movement in the blade-type mixer. And peristalsis zone was dominated by shear mixing, sliding zone was dominated by strong shear mixing, throwing zone was dominated by strong shear mixing and diffusion mixing along with weak convective mixing. And the position, size, shape of each zone were highly affected by the structure and operation parameters of the blade-type mixer. Under the condition of loading coefficient of 65%, which was determined by preliminary experiments, blade width, rotation speed and mixing time were used as experimental factors, variation coefficient was chosen as evaluation indicator, then experiments were done based on three factors five levels orthogonal rotation combination experimental method. Results showed that the descending order of effects of various factors on variation coefficient was rotation speed, mixing time and blade width. When blade width was 138mm, mixing time was 4.7min and rotation speed was 32.5r/min, the variation coefficient was 3.11%. The research results of the blade-type feed mixer could provide reference for the optimum design of feed mixers.

Abstract:In view of cantilever multistage centrifugal pump in operation process is prone to vibration of shafting and bring reliable and stability problems, due to its unique suspension center cantilever rotor structure. The rotor axis trajectory of cantilever multistage centrifugal pump was explored under design flow through combination of numerical simulation and experimental verification. Cantilever multistage centrifugal pump rotor dynamic characteristics in the operation was not only influenced by the uneven quality of unbalance mass, but also influenced by sealing fluid excitation force, fluid excitation force induced by chamber and fluid added mass. The dynamic model of the cantilever multistage centrifugal pump was simulation with the above calculation results so that the influence of sealing fluid excitation force, fluid excitation force induced by chamber and fluid added mass on the rotor axis trajectory could be calculated. Furthermore, the simulation results were compared with those of the model without sealing fluid excitation force, fluid excitation force induced by chamber and fluid added mass, the model with sealing fluid excitation force only, the model with both sealing fluid excitation force and fluid excitation force induced by chamber and the model with all excitation. Finally, the simulation was verified by the test of rotor axis trajectory. The results showed that the sealing fluid excitation force of the ring of impeller improved the stability of system, compared with the rotor with no sealing excitation force, and reduced the radial displacement amplitude. Fluid excitation force induced by chamber increased the cross stiffness of rotor system led to an increase in the amplitude of vibration. Fluid added mass compared with sealing excitation force and fluid excitation force induced by chamber had a remarkable effect on transient response of cantilever rotor system and the magnitude of displacement nearly gapped two orders of magnitude. The research provided reference for improving the operation stability of cantilever structure optimization of multistage centrifugal pump.

Abstract:Centrifugal pumps are widely used in various fields. The cavitation not only causes the destruction of over-current components so as to influence the reliability of operation, but also affects the pump running stability because of vibration noise. In many cases, cavitation is unavoidable. Therefore, it is necessary to improve the accuracy of cavitation monitoring and reduce the unnecessary loss caused by cavitation. The objective was to study the variation law of noise characteristics under different cavitation conditions of centrifugal pump, and the influence of cavitation development on hydrodynamic noise. The previous scholars used the test methods to get the noise signals, but the signals were not the same as different product characteristics of pumps. Therefore, it is a cost-effective method to predict the cavitation noise by numerical simulation. And the experimental method was used to verify the accuracy of numerical calculation. Firstly, an ultra-low specific speed centrifugal pump was used as the research object to build a closed test bench. Based on the pump product test system and data acquisition system, a test system of centrifugal pump cavitation noise and performance was established to realize pump performance parameters and internal field noise signals synchronization acquisition. The cavitation performance curves of the model pump were predicted by Kunz cavitation model and Zwart cavitation model respectively. And the experimental values were compared with to select the appropriate cavitation model. According to the vapor volume fraction distribution among blades and cavitation performance curve, the whole cavitation process was divided into noncavitation stage, nascent cavitation stage, feature cavitation stage and serious cavitation stage. The effects of cavitation on internal flow field and pressure at different times during pump operation were analyzed. The acoustic boundary element method was used to transform the flow field information into sound field information. The relative error of the noise prediction value and the experimental value of each cavitation stage was compared to verify the feasibility of the forecasting method. Because the analog signals show high degree of coincidence with the actual signals. Finally, the influence of cavitation on the internal sound field was studied based on the flow sound coupling method. The study showed that for the cavitation on ultra-low specific speed centrifugal pump, Zwart model had better applicability compared with Kunz model. The relative errors between the predicted value and the experimental value of the Zwart model were all within 5% in the non-cavitation stage, the feature cavitation stage and the serious cavitation stage. The cavitation deteriorated the flow regime in the flow channels, especially from the feature cavitation stage. The number of internal vortices was increased and pressure fluctuation was increased because of the vapor, which made the increase of instability. The variation of the inner field noise signal with cavitation was complicated. In the low to middle frequency range, the sound pressure level of the discrete component of blade passing frequency and its harmonic frequencies were gradually decreased with the development of cavitation, due to the inhibitory effect of cavitation on dynamic and static interference;while the axial frequency component showed an increasing trend. The sound pressure level in high frequency range was decreased firstly and then increased sharply with the decrease of the cavitation coefficient. The high frequency eigenvalue component was gradually submerged in the wide frequency band. The increase of the sound pressure level in the high frequency band caused the total sound pressure level risen. Compared with the experimental results, the relative error was less than 5% in the non-cavitation stage and nascent cavitation stage. In feature cavitation stage and serious cavitation stage, the degree of coincidence was slightly worse, and the relative error was less than 10%.

Abstract:In order to identify effects of staggered blades on cavitation characteristics of double-suction centrifugal pump, considering the influence of the shrouds of pump and fillet, the blades of both sides of the impeller were separated circumferentially at 0°,10°,15°,20° and 30° staggered angles, respectively. RNG k-ε turbulence model and Rayleigh-Plesset equation were applied to simulate cavitation characteristics and performance test under design conditions. In order to highlight the generality of the research conclusion, the definition of staggered degree was introduced and the vapor volume fraction on the middle stream surface of impeller and head and the variation of the impeller torque at different staggered degrees were analyzed. Compared with experimental values, the results indicated that the prediction results were accurate to some extent;it can be seen that the selection of reasonable staggered degree can improve the performance of anti-cavitation. At different staggered degrees, the corresponding net positive suction head values were different when the impeller torque was subjected to a sharp decrease, when the staggered degree was at 1, the impeller torque was stable in cavitation and relatively less in cavitation;when net positive suction head was under critical net positive suction head, the region of static pressure was lower than the local cavitation pressure at the double-suction centrifugal pump impeller channel and the vapor occupied the least flow area at the flow channel, staggered degree at 1 was the least. Therefore, the cavitation characteristics were relatively good when the staggered degree was at 1 to provide a theoretical basis for improving the cavitation characteristics and the safe operation of double-suction centrifugal pump.

Abstract:S-shaped shaft extension pump is an important device for low-lift pumping station. The efficiency of the existing S-shaped extension pump system can not satisfy the users, so it is difficult to be applied to the practice. Based on CFD numerical simulation, an optimization of the traditional S-shaped bend was made, a new S-shaped shaft extension pump scheme was proposed. A whole flow passage of the system was obtained. The results displayed excellent flow characteristics of the system and the axial velocity uniformity at outlet section of the suction passage at different flow rates was over 99.2%;the efficiency of the system was higher than 77.1% from the pump performance prediction which was approved by the model test. The model pump test was conducted in a high accuracy test standed for hydraulic machinery to validate the numerical results. Under the blade angle of -4°, -2°, 0° and 2°, the lifting heads were between 1.7m and 2.0m, and the maximum pumping efficiencies reached 77.1%~78.35%, which met the higher requirements for application in practice. The horizontal S-shaped shaft extension pump system was successfully applied to a pumping station of Gold-Dam water diversion project in Yangzhou City. The field test of pumping station showed that the hydraulic performances of the high efficient planar S-shaped shaft extension pump system for the prototype system and the performance results of the model system test were basically coincident. The pump units were running stably, and vibration and noise were small. The high efficient planar S-shaped shaft extension pump system had advantages in simple structure, compact layout, less occupation of land, large working space, convenient installation and maintenance. The operation cost of the pumping station would be low due to the hydraulic losses of the system were significantly reduced, especially for the long-running pumping station which had effects on energy saving and consumption reducing;and it was convenient to be used in small and medium sized pumping station to implement standardized construction.

Abstract:Pressure fluctuation in vertical axial-flow pumping system caused by outlet flow pattern of inlet conduit is the primary sources of operation instability. By means of pressure transduces and red threads installed in outlet section of inlet conduit, fluctuating pressure signals were obtained and recorded under various operating conditions. The signals in time and frequency domains of the signals were analyzed by using short-time Fourier transform method. The results showed that when the flow rate was less than 0.7Qbep, the deviation direction of red threads of internal wall were the same as the impeller rotating direction in inlet conduit, while the flow rate was larger than 0.7Qbep, the deviation direction of red threads of internal wall was along the axial direction. With the increase of rotational speed, the pulsating amplitude of each measuring point was increased at Q<0.7Qbep, while with the increase of rotational speed, the pulsating amplitude was gradually decreased. The pulsating amplitude was decreased firstly and then increased with the increase of flow rate at the same rotational speed, and the pulsating amplitude was the minimum under the optimum operating condition. The main frequency of each measuring points was four times of rotational frequency at different rotational speeds. The subdominant frequency of each measuring points was one time of rotational frequency in Qbep. Both flow rate and rotational speed had significant influence on the subdominant frequency of outlet section in inlet conduit under small and large flow rate conditions. With the increase of rotational speed, the increase amplitudes of measuring point pulsating amplitudes were different under different operating conditions. The pressure fluctuation amplitude was larger in the frequency range of 0 ~ 8 times of rotational frequency for inlet conduit outlet section at different rotational speed.

Abstract:The model of speed-governing performance of axial flow pump device was deduced by combining theory with experimental data, and by using multiple nonlinear regression analysis method. The study of the model was aimed at a present situation that there was no speed-governing performance model with clear physical meaning. With this model, the study of speed control strategy can go further. Firstly, the characteristic equation of head, efficiency about speed and flow was deduced by the basic equation of water pump, combined with some assumptions. And then a conclusion that the efficiency and head characteristic curve was shown to be nonlinearly variable by the change of speed which was given by the test of two different types axial flow pump devices on the high-precision hydraulic machinery test bed. The undetermined coefficients of characteristic equation were concluded by multivariate nonlinear regression algorithm combined by ‘nlinfit’ function and genetic algorithm, using experimental data as the observation value, and using the characteristic equation as the predictive model. By comparing ‘nlinfit’ function with genetic algorithm, it was clear that the coefficient solution tended to locally optimum by using ‘nlinfit’ function only. And it tended to globally optimum by combining with genetic algorithm. By comparing the experimental data with prediction model, both of which are of two different types axial flow pump devices’ speedgoverning performance of head and efficiency, it showed that on the whole area, the head error between prediction model and measured value was 0~0.8m, and the efficiency error was 0~8%. On the area nearby the design point, the head error between prediction model and measured value was 0~0.5m, and the efficiency error was 0~5%.

Abstract:Land use zoning is the basis and key elements of the overall land use planning. It is important to determine the future land use direction, formulate the land use structure and spatial layout adjustment strategy, and realize the regional land differentiation management and sustainable utilization. As the most important commodity grain base in China, Northeast China has a significance to the national food security. However, the economic development level of different provinces in Northeast China is quite different. The development of regional economy is unbalanced.The index system of characterizing the three-dimensional state of land use in the main grain producing areas was constructed, and the two-dimensional graph theory clustering method and GIS spatial analysis method were used to study the land use zoning of 184 county-level administrative units in northeast region, and differentiated land use regulation measures were put forward. The results showed that the three-dimensional evaluation index system of land use can clearly reflect the natural background condition, development status and future development potential of land use;the results of land use zoning in Northeast China obtained by two-dimensional graph clustering and GIS qualitative analysis had good spatial continuity as well as zoning integrity, which improved the feasibility and scientificalness of land use zoning. The northeast region was divided into twelve zones consisted of three city comprehensive development zones, two agricultural and animal husbandry land use zones, one agricultural and forestry land use zone, one agricultural, forestry and animal husbandry land use zone, five forestry and agricultural ecological zones. The research had certain reference significance for the management of land use in the main grain producing areas.

Abstract:The vegetation temperature condition index (VTCI) has been widely used in drought monitoring, which is in the assumption that their shape of the scatter plots of normalized difference vegetation index (NDVI) and land surface temperature (LST) was a triangular at a regional level. Bsaed on the vegetation temperature condition index (VTCI) drought monitoring results retrieved from the moderate-resolution imaging spectroradiometer (MODIS) data products (MODIS-VTCI) and the relative VTCI derived from the Landsat OLI/TIRS products (Landsat-VTCI) in the Guanzhong Plain, China, the MODIS-VTCI was transformed from a coaser resolution of 930m to a finer resolution of 30m by using the point spread function, called PSF-VTCI, and the PSF-VTCIs were validated for their quantification. The results showed that there was good agreement between the PSF-VTCIs and the Landsat-VTCIs terms of their correlation coefficient and structural similarity index. The correlation coefficients between the PSF-VTCIs and the cumulative precipitation were similar to those between the MODIS-VTCIs and the cumulative precipitation, which were both larger than those between the Landsat-VTCIs and the cumulative precipitation, indicating the PSF-VTCIs were not only related to the space heterogeneity of the Landsat-VTCIs but also the accurate quantitative drought monitoring results of the MODIS-VTCIs.

Abstract:Crop type classification is one of the most significant applications in polarimetric synthetic aperture radar (PolSAR) imagery. As an advanced remote-sensing technique, PolSAR has been proved to provide high-resolution information, including the intensity and polarization of illustrated land surface. However, single-temporal PolSAR data are restricted to provide sufficient information for crop classification and identification. With the increase of number of airborne and spaceborne PolSAR systems, a large number of real PolSAR data are generated, and thus provides opportunities for multi-temporal data analysis. The potential of improving crop classification accuracy by introducing the differential characteristics of H/α parameters for multi-temporal PolSAR images was investigated. Firstly, by analyzing the characteristics of several typical crops in different growing stages, a new parameter was defined for the first time to describe the differential characteristics of H/α distribution. Therefore, a new supervised classification method with the newly defined parameter was proposed to classify different crop types. The main idea of the proposed method was to apply various features of classical H/α parameters to improve the accuracy of crop classification. A validation test for the new approach was performed with Sentinel-1 data sets which were simulated by Radarsat-2 data sets and provided by ESA. The results showed that the mean accuracy of the proposed method was improved by 4 percentage points compared with the supervised complex Wishart classifier when the six kinds of crops were classified. Furthermore, the number of classes was reduced to 4 and the accuracy was almost improved by 6 percentage points.

Abstract:Aiming at solving the low-accuracy and slow-speed problem of traditional registration, an improved SIFT-ICP registration method for color point clouds of plant was put forward. Original color point clouds of plant was merged by color images and depth images obtained by Kinect from different perspectives. Firstly, preprocessing was carried out to extract point clouds of plant from original point clouds, in which lots of point clouds of background and noise were involved. Secondly, by making use of depth features and boundary characteristics of plant point clouds, the key points were detected by means of SIFT (Scale invariant feature transforms) algorithm. Thirdly, normal calculation was executed on the key points computed previously, which was revised by adapting the estimation to accelerate the normal estimation process. The normal estimation was determined by the number of surrounding points. For the sparse part of point cloud, the value of adjacent point was reduced, on the contrary, it was increased in the process of normal estimation. Meanwhile, the FPFH (Fast point feature histograms) descriptor was developed to obtain the characteristic vector which contained 33 dimension element for each key point. Fourthly, SAC-IA (Sample consensus-initial alignment) algorithm, an initial registration algorithm, was applied to register plant color point clouds from different perspectives to provide a better spatial mapping relationships for accurate registration. Finally, on the basis of initial registration, the ICP (Iterative closest point) algorithm, which was accelerated by adapting Nanoflann instead of Flann, was used to refine the initial transform matrix inferred by initial registration. Experiments showed that this registration method can improve not only registration speed but also registration accuracy, the average Euclidean distance between corresponding points was below 7mm and registration time-consuming was less than 30s.

Abstract:In recent years, information management system (IMS) has been widely applied to every different fields. A series of problems arose because most developers only focused on the design and implement of their own application systems. It caused resources to be wasted in various fields. Meanwhile, the system development efficiency was low, and the expansibility and versatility of system were poor. The object was to design and implement a reusable software system to meet the common demands of information collection and statistic system in IMS. The dynamic data transmission management system (DDTMS) was based on table-driven methods, and it contained data access component, data verification component, vacancy data filling component and statistical result query component. Each component performed specific functions. The dynamic data transmission management system was developed on Visual Studio 2013 platform. Lots of technologies were used to finish the reusable software system like factory pattern, dynamic compilation, jQuery and C#, and so on. In order to test the data transmission management system sufficiently, it was applied to two systems. One system was Chinese forestry ecological resources environmental bearing capacity: data dispenser, and another system was China ecological security index system. The experimental results showed that the reusable software system was practical and stable. It was of good versatility. And it had greatly improved the development efficiency and the expansibility of system.

Abstract:Based on the principle of photogrammetry, image-processing technology and forest measurement, the forest telescope intelligent dendrometer composed of PDA module, remote EDM module, telephoto lens CCD and rotational station was developed to obtain the parameters such as inclination angle, azimuth angle, remote distance and image information. By using Java language and developing in Android Studio 2.1 systems development environment, the functions such as tree height measuring module, DBH measuring module, micro-sample plot measuring and basic measurement can be achieved. Verified by experiments, the measuring accuracy of tree height was as high as 93.32%, DBH was as high as 96.49%, stand average height was as high as 94.47%, stand average DBH was as high as 91.68%, stand density was as high as 86.04%, and that of stand volume measurement was 82.64%. It showed that the equipment can solve problems such as observation difficulties of non-arrival points and measurement difficulties of visible factors. Therefore, it can be used and promoted in the forestry inventory in the future.

Abstract:In order to realize the rapid and accurate determination of diameter at breast height (DBH), EAN-13 bar code encoding and decoding rules was taken as template, based on the Android platform and Open CV intelligent image processing technology, an electronic bar code ruler was designed and implemented to realize the automatic measurement of the tree DBH size by single operation. When the bar code encoding was completed, bar code image was scanned by using mobile phone APP, through image preprocessing, bar code identification, location and diameter automatic measurement and recording, data storage and export process, the automatic measurement of DBH in forest survey was realized. By selecting 205 samples of coniferous trees and 200 broadleaf trees, the electronic bar code was used to measure them, at the same time, the measurement results were compared with the precision of the traditional measuring ruler. The experimental results showed that the measurement accuracy of the method can be more than 99.95%, which can meet the precision requirements of continuous logging of national forest resources. Meanwhile, the method of measuring tree breast diameter of each tree was only 11 to complete the work of measuring diameter, and the measuring work efficiency was greatly increased. This method had good application prospect of the tree DBH measurement in forest survey.

Abstract:Preferential flow is the phenomenon of water and solute rapidly transport through preferential flow paths such as macropores, wormholes and root holes. Studying the development degree of preferential flow has a certain reference value for efficient use of agricultural fertilizer and prevention of groundwater pollution. With the purpose of evaluating the development degree of preferential flow under different slope farmlands in Chongqing purple sandstone area, the dye tracer experiments were designed in three sample regions (pumpkin, citrus and maize). The morphological and statistical methods were used to extract parameters from the image of soil profile in three slope farmlands. Multi-index evaluation method was used to determine the preferential flow indicator PFI. Combined with fractal theory in geometry, the development degree of soil preferential flow was quantitatively evaluated. Six characteristic preferential flow indexes (staining area ratio of preferential flow area, uniform flow infiltration depth, preferential flow fraction, length index, peak index and coefficient of variation) revealed that the preferential flow of pumpkin and citrus was higher than that of maize;the order of preferential flow indicator PFI from large to small was pumpkin (0.88), citrus (0.77) and maize (0). Box-counting dimension calculation of wetting front curve can characterize the non-uniformity of soil water infiltration. The larger box-counting dimension was, the more irregular shape of wetting front curve and the higher degree of preferential flow development were. Fractional dimension of wetting peak trace calculated by Fractal Fox 2.0 software basically got the same result, which showed that it was feasible to evaluate the development degree of soil preferential flow quantitatively. Fractional dimension with advantages of simple operation, low cost and high accuracy was suitable for field scale, which can enrich the study method of soil preferential flow.

Abstract:Chanan Irrigation Area of Ili was selected as the study area. Through the combination of electromagnetic fast soil electrolytic conductivity acquisition technology with laboratory analysis, and using the construction of soil salinity interpretation model to get soil salinity content of 0~30cm, 30~60cm and 60~100cm soil layer in the autumn of 2015 and 2016. On the one hand, simple statistical classification was conducted, and the semi-variogram analysis and spatial interpolation analysis for soil salinity characteristic factors were carried out;on the other hand, the elevation information of the study area was extracted, and the buffer area through investigating the influence of river was analyzed, which aimed at constructing suitable magnetic induction type fast precise diagnostic evaluation and utilization planning technology for the study area and the same irrigation area. Preliminary studies indicated that: firstly, from the autumn of 2015 to the autumn of 2016, non-saline soil area was significantly reduced, while moderate-saline soil area was significantly increased, there was a trend that non-saline soil and mild-saline soil were evoluted to moderate-saline soil. Secondly, soil salinity in the study area had a migration trend to central and eastern regions, with an increasing trend of salinization area and the average of salt content. Moreover, both the river and the terrain were the main influence factor of soil salt movement, while the river was the main influence factors on the large scale of space, and the terrain was the main influence factor on the small scale space.

Abstract:Water resources have become a key factor for restricting the social, economic and agricultural development of arid area in Northwest China. In recent years, agriculture in arid oasis has developed rapidly, and human activities have seriously affected balance on the regional soil moisture, resulting in a large area of salinization. Therefore, the monitoring of soil moisture is of great practical significance to the development of oasis agriculture and economy. Taking the oasis of Weiku in Xinjiang as the study area, totally 41 soil moisture samples and hyperspectral data of the oasis vegetation in arid area were collected, and the vegetation index was taken as bridge. Multiple regression (MLSR), partial least squares (PLS) regression and support vector machine regression (SVR) were used to establish the inversion model of soil water content in oasis, respectively, the regression models were tested respectively. The experimental results showed that the accuracy of different models was different. Through the optimization of parameters and extraction of optimal test set, the fitting effect from good to bad was improved SVR model, PLS model and MLSR model, which were based on the vegetation The improved SVR model had a good fitting effect, R2 was 0.8916, RMSE was only 2.004, the analysis accuracy in the oasis of arid area reached the practical prediction accuracy. The R2 values of MLSR model and PLS model were 0.6300 and 0.6549, and RMSE were 3.001 and 2.749, respectively. The results showed that it was an effective method to improve the monitoring accuracy of shallow soil water content in oasis, and it can also provide more data for monitoring soil moisture in arid area.

Abstract:At present, the study about historical mining wasteland as the object, the spatial distribution characteristics of reclamation soil quality and the relationship between the spatial distribution characteristics of soil quality and the response to reclamation measures are rarely reported in the literature. Based on classical statistics, variation function theory and empirical Bayesian Kriging method, the southwest area of historical sulfur mining wasteland reclamation area as the research object, from two aspects of point and area, the spatial distribution characteristics of reclamation soil heavy metals were systematically analyzed, and the quantitative relationship between them and reclamation measures was revealed. The results showed that the combined method of classical statistics, geostatistics and empirical Bayesian Kriging was feasible to reveal the spatial distribution characteristics of soil heavy metals. The variation coefficients of heavy metals in the five soils were larger, which were consistent with the characteristics disorder, the variability and the spatial uniformity and the abrupt change of land reclamation. The enrichment coefficient of heavy metals in soil was more than 2. Under the interaction of mining, reclamation measures and topography interaction, the heavy metals in different soils had a certain similarity in the global space, in the northsouth and eastwest basically showed two low and high in the middle of the inverted “U” trend. The C0/(C0+C1) of most heavy metals of reclaimed soils was 50%, and the random factors, such as soil cover, soil fertility and soil pH value regulation, were dominant in the spatial variation of different heavy metals. No matter what kind of heavy metals, the eastern of the first region, the northern of the second region, and the western of the fourth region had higher heavy metal content;the western of the first and second regions, the northern of the third region was relatively low. The average content of heavy metals in forest land and grassland was higher than that of cultivated land, and the heavy metal pollution, especially the Cd, was needed to control the heavy metal pollution in the future. With the increase of the effective soil layer thickness, the heavy metals in the soil showed a decreasing trend. There was no significant difference of soil heavy metal between the effective soil layer thickness in 30~100cm, which suggested that the effective soil layer thickness of the reclaimed soil in the study area was 100cm or more. As soil pH value became smaller, the total heavy metals in reclaimed soil showed an increasing trend, but the control of pH value to reduce the content of heavy metals in soil needed to be maintained at a certain extent, the pH value of proposed study area was continuously controlled in 7 ~ 8. The research results would provide guidance on the method of quality monitoring for the reclamation of abandoned industrial and mining land, and provide a scientific basis for historical mining wasteland reclamation soil heavy metal pollution further control and management.

Abstract:A large number of soil heavy metal content data and spatial data were obtained through soil survey and laboratory analysis. Spatial variability of soil heavy metals were analyzed by ordinary Kriging (OK) and classical statistical analysis. The pollution risks of each soil heavy metals were studied by utilizing indicator Kriging (IK) and the integrated risk of soil pollution was calculated by multiple variable indicator Kriging (MVIK). Results showed that the contents of heavy metals of As, Cd, Cr, Cu, Pb, Hg, Ni and Zn in karst area were obviously higher than those in non-karst area. They were significantly correlated with each other (p<0.01), meaning that they were of the same source. The value of correlation coefficient between Zn and Cd was the highest, and the value of correlation coefficient between As and Cd was the lowest. All the soil heavy metals had significant correlations with pH values (p<0.01). All the heavy metals had strong spatial variability with exception of Cu, due to the intrinsic factors, including the lithology and soil forming rock. The high values of heavy metals were in the southeast and north of the survey area, and the low values were in the southwest area. There were pollution risks for As, Cd, Cr, Cu, Pb, Hg, Ni and Zn, and the risk probabilities of them were 0.326, 0.805, 0.185, 0.192, 0.267 and 0.270, respectively. Therefore, there was high pollution risk for Cd. The probability for integrated risk of soil heavy metals pollution was 0.335. The study provided scientific consults for the industrial and agricultural production and the environment management.

Abstract:In order to grasp the movement law of soil water and solute in dual point source drip irrigation, and provide reference for the design and management of drip irrigation of navel orange in red soil hilly areas, a mathematical model for water and nitrate nitrogen transport in five different red soil bulk densities was established. With the help of Hydrus-3D model, the soil water and solute distribution characteristics and wetting front transition and confluence process were simulated under the different red soil unit weights, the same drip discharge and nitrogen application rate. The simulation results were in good agreement with the test results: the deviations of simulated wetting front migration and confluence process, wetting zone soil moisture content and NO-3-N content between the measured and simulated values were less than 9.5%;the simulated and measured values were in good agreement, and it showed that the confluence of soil moisture and NO-3-N content in the same depth was below the wetting front under the drip soil, and red soil in high density hindered the wetting front velocity. Overall，Hydrus-3D can be used to simulate the wetting zone and the transport and distribution of water and nitrogen under drip irrigation fertilizer irrigation and red soil irrigation.

Abstract:An improved hidden Markov prediction model (IL-HMMs) based on incremental learning was developed, which was based on the prediction of regional groundwater table in the typical county of Dengkou, a typical arid region in Northwest China. In order to test the IL-HMMs model prediction results, the predicted results was compared with the measured data of 2013, and the results of hidden Markov model (HMMs), weighted Markov chain (WMCP) and BP neural network (BPNN) prediction model. The results showed that compared with other forecasting models, the prediction accuracy of IL-HMMs model was improved significantly, the error was smaller and the robustness was better. The groundwater depth in 2018 was predicted by using the IL-HMMs model. The prediction results showed that in 2018 the average annual groundwater depth would be increased slightly and the groundwater depth would be increased in some areas. The IL-HMMs model of groundwater depth prediction had good stability and robustness, it can provide ideas and methods for the dynamic prediction of groundwater depth, and also provide an important basis for the development, utilization and protection of groundwater resources in the region. Tracking and monitoring the change of water level, preventing the groundwater level from falling continuously and making emergency response plan can be utilized to realize the sustainable development and utilization of water resources.

Abstract:Irrigation areas, as the major wheat producers in China, are facing water resources and environment problems which were led by huge water and fertilizer consumption in wheat production. To comprehensively assess these issues, the total water footprint (WFT) of wheat and production water footprint (WF) for per unit mass of wheat were calculated based on monthly meteorological and agricultural data from the Baojixia Irrigation Area (BIA) during the period of 1994—2010. Mann-Kendall trend test and the GIS based inverse distance weighted spatial interpolation were applied to analyze the temporal and spatial variations of wheat water footprint indices. Furthermore, the logarithmic mean Divisia index decomposition (LMDI) method was employed to quantify the contributions of driving factors for changes in WFT. The result showed that the average values of wheat WFT and WF were 673 million m3 and 1.04m3/kg, while the green, blue and grey components accounted for 34.51%, 30.16% and 35.33%, respectively. The WFT and WF of wheat were declined significantly with slops of -17 million m3/a and -0.02m3/(kg·a), respectively. The averages of WF and its green and blue components (1994—2010) rose gradually from southeast to northwest in BIA, however, the grey production water footprint was increased from center of the BIA to both sides. By LMDI method, the WFT in BIA was highly depended on human activities (-113.57%) rather than climate change (13.57%). The driving factors in order of importance were irrigation quota (-56.58%), total plant area (-55.78%), rate of wheat plant area (-43.76%), nitrogen fertilizer per hectare (39.96%), climate change (13.48%) and irrigation water utilization coefficient (2.59%). Excessive fertilization was common in BIA, which caused serious water pollution and huge amount of grey consumption. Meanwhile, the low irrigation water utilization coefficient in BIA led to more water wasted in conveyance. Based on the research, the practical suggestions for improving WFT and WF were fertilizer reduction and construction for high irrigation water utilization coefficient.

Abstract:Forest floor moisture measurement plays a significant role in the research of forest hydrology, carbon cycle, forest fire spread and risk evaluation. A detection method of forest floor water content based on standing wave ratio (SWR) was introduced. The developed SWR sensor with two parallel anular probes could measure the water content and electrical conductivity in forest floor or mineral soil by using time-sharing multiplexing technology. Experimental results showed that the relationships between the output voltage of SWR sensor and the water content of partly decomposed forest floor, well decomposed forest floor and mineral soil were linear, respectively. Compared with the commercial TDR sensor, the SWR sensor showed a better performance with smaller mean absolute error and lower cost in the measurement of forest floor and soil water content. In addition, the SWR sensor had obvious advantages when the forest floor layer was thin (<10cm). It was notable that the partly decomposed forest floor might be decomposed completely in the long-term in situ moisture measurement. Therefore, the developed sensor estimated the decomposition rate by detecting electrical conductivity of forest floor, which would lay a foundation for the accurate measurement of forest floor water content.

Abstract:Bacillus amyloliquefaciens is a kind of plant growth promoting rhizobacteria (PGPR). This kind of beneficialrhizosphere bacterium plays a key role in increasing soil fertility, promoting plant growth and suppressing the growth of phytopathogens in the field of agriculture. This characteristics of growth-promotion and antibiosis of Bacillus amyloliquefaciens L-H15 was studied. Genes which were relevant to the characterizations of growth-promotion and antibiosis of B. amyloliquefaciens L-H15 were analyzed based on the complete genome sequencing. Meanwhile, the capabilities of biofilm formation, nitrogen fixation, phosphate and potassium solubilization, production siderophores and phytohormones were measured. The results indicated that L-H15 showed the capability of biofilm formation and the amount of bacteria which could colonize the root surface was up to 105CFU/g. The relative expression of siderophores was 60.22%, and the production of IAA, CTK and GA could reach 61.35pmol/L, 48.93ng/mL and 82.46pmol/L, respectively. The diameters of inhibition zone were (8.67±1.15)mm and (2.50±0.50)mm, respectively, when cocultured L-H15 with two fugal pathogens, i.e., Rhizoctonia solani and Fusarium oxysporum. In conclusion, L-H15, which showed excellent characterizations in both aspects of growth-promotion and antibiosis, had great potential to become a biological control agent in the future.

Abstract:Stem water content is an important parameter for evaluating plant physiological water conditions. Poplar trees were selected as research objects. The estimation model of stem water content was proposed by analyzing the variation relationship between stem water content and micro-environment parameter set. Considering the multi-collinearity between micro-environment parameter set, the maximum principal component PC1 of micro-environment parameter set was chosen as a feature variable via principal component analysis. The feature variable retained 98.89% of the original data information. In addition, the complexity of model was simplified by reducing the data dimension. PC1 as the input variable and stem water content as the output variable, the oblique ellipse model between the two was established. In six sunny days with similar micro-environment, the mean error of the model was less than 0.05%, root mean square error of the model was less than 0.06%, and decision coefficient of the model was greater than 0.94. The oblique ellipse model can precisely estimate real-time stem water content, but because of the differences in morphological indexes of poplar trees, the estimated parameters of different oblique ellipse models between stem water content and PC1 were different. Moreover, the estimation model of stem water content should be respectively established according to different seasons and weather environment.

Abstract:Tar removal and energy recovery of tar are two main problems, which hinder the development of the clean and efficient combustion technology of pyrolysis gas. Based on the combustion technology of fuel gas, the design of a new type of pyrolysis gas burner and study on the pyrolysis gas combustion and emission characteristics were focused on. According to the quantity of the pyrolysis gas, the treatment capacity of the burner was 2~5m3/h. The parameters of the burner were determined by theoretical calculation. The experiment platform consisted of gas burner, combustion chamber, catalystic cracking equipment and flue gas analyzer. Pyrolysis gas originated from peanut shell continuous carbonization flowed into gas burner without condensing. The carbonization temperature and retention time were 500℃ and 30min. The direct combustion test and catalytic combustion experiment were carried out, respectively. The experiment results indicated that the gas burner was working well. The combustion of pyrolysis gas was stable and combustion efficiency could amount to 98.5%. However, under the action of the catalyst, the combustion efficiency was increased to 98.9%, while the nitrogen oxides produced was increased by 20mg/m3. The research results provided an important reference for the development of high efficiency clean utilization technology of pyrolysis gas. The location of the catalytic cracking unit would need to be studied.

Abstract:Char from lauan pyrolysis was used as feedstock, and its structure and surface properties were improved through physical and chemical activation way with microwave-assisted method and the traditional calcination method. After being activated, the biochar was characterized by various characterization techniques, including nitrogen adsorption, scanning electron microscope, X-ray diffraction, thermogravimetric analysis and Fourier transform infrared spectroscopy. The results showed that the activated biochar had abundant micropores and mesopores which formed a multilevel pore structure, and the surface area of the micropores accounted for 36%~48%. In addition, the biochar activated through microwave pretreatment and N2 atmosphere calcination had a high surface area of 1224m2/g. The uniform microwave heating produced micropores and the mesopores were further formed through calcination. The efficient synergistic effect of both the two thermal treatments led to the high surface area and multilevel pore structure. The activated biochar yield of 42% was obtained under the condition of microwave pretreatment and N2 calcination. Besides, different activation methods had a significant effect on the infrared properties of biochar, and the oxygen-containing groups on the surface of activated biochar were greatly reduced. The thermal stability of biochar after activation was significantly improved and there were no apparent weight loss peaks, which was beneficial for the utilization of biochar as catalyst support.

Abstract:The effects of vent configuration and wind regime on the microclimate in the tunnel greenhouse were numerically investigated. A full scale computational fluid dynamics model (CFD model) was constructed based on a tunnel greenhouse cultivated with water spinach in eastern China. The model was firstly validated by comparing CFD simulations with experimental temperatures. The simulations had similar trends to those of the experiments with less than 1.1℃ of difference. It was then employed to investigate the greenhouse airflow and temperature patterns with different vent configurations, evaluate the effect of vent configuration on the ventilation rate, temperature difference between inside and outside, and the inside climate homogeneity, and reveal the greenhouse microclimate mechanism with different wind regimes. Simulations showed that different vent configurations induced different inside microclimate patterns and ventilation performances. The roof plus side opening provided the highest ventilation rate, the minimum temperature difference and a relatively uniform indoor climate, and thus can be recommended for summer ventilation. Wind regime had a significant impact on the airflow and temperature patterns in the greenhouse, which considerably affected the cooling performance and the indoor climate homogeneity. With the weather conditions of high temperature and low wind speed, thermal driven ventilation played a remarkable effect on the greenhouse microclimate. The roof and side opening can improve greenhouse cooling performance remarkably and reduce air temperature in crop canopy effectively.

Abstract:In order to ensure the supplement of healthy seedlings in tomato anniversary production, the effect of different light qualities on the growth characteristic of tomato seedlings was investigated during different periods in the artificial climate environment, and the optimal artificial light was confirmed for the seedlings. LED was chosen as the experimental light. Because the small size, durability, long lifetime, cool emitting temperature, and the specific wavelengths for a targeted cultivation made them more suitable than traditional light sources. Therefore, three treatments of mixed red and blue LED qualities of RB3/1, RB5/1 and RB7/1 and white LED (W) were used to illuminate the tomato seedlings with the photoperiod of 12h/12h and the natural light irradiation as the compared treatment. The comprehensive evaluation method was adopted to analyze the effect of different light qualities on the growth characteristic of the tomato seedlings during different periods. The results showed that the employment of white LED and the combination of red and blue LED as the single light source in an artificial climate system could meet the requirement of tomato seedlings growth. Light quality had extremely significant effect on the hypocotyls length, leaf area and ratio of root to shoot (P<0.01). Light quality had no effect on plant height, stem diameter, number of roots, root length, biological mass, seedling index and G value during early period and then it was turned into significant level (P<0.05). The influences of light quality on these indicators differed during different phases at the same time. According to the results of comprehensive evaluation method within each phase, the optimal light formula was determined: RB7/1 maintained for two weeks after germination and then was replaced by white LED for the next stage of cultivation. While the RB3/1 treatment, which got the lowest comprehensive evaluation score and was inferior to the control group, was not suitable as the single light for tomato seedlings growth obviously. This research provided references for both of the selection of artificial light source and a model of tomato seedlings cultivation for short-time cultivation tomatoes in greenhouse.

Abstract:Sound analysis has become an important tool for studying the behavior, health and welfare of animals in recent years. Monitoring laying hens’ sound can be used to evaluate their health or welfare. However, large-scale henhouses exist more noise interference such as a typical fan noise, which has a great effect on accurately recognizing poultry vocalization. Hy-line brown laying hens were taken as an example and poultry sound signal pretreatment was applied for reducing the fan noise interference as far as possible. Different types of laying hens’ vocalization and fan noise were recorded by digital sound collection platform. LabVIEW software was used for sound signal processing and analyzing time-frequency characteristics of the fan noise as well as poultry vocalization. Meanwhile, compared with different noise reduction methods, including IIR filter de-noising, wavelet threshold de-noising and improved spectral subtraction methods, and the effect of different de-noising methods were evaluated. Results showed that the sound frequency of laying hens were mainly distributed between 400Hz and 2500Hz, and fan noise frequency distribution was between 0Hz and 1000Hz. In the acoustic environment of SNR within -8~20dB, the improved spectrum subtraction method had the minimum root mean square error (0.03~0.38) with the shortest processing time (6~7ms), which had good outcome in practical application. This study provided foundation for analyzing laying hens’ vocalization in fan noise environment of large-scale henhouses.

Abstract:High-density mode was widely adopted in China’s aquaculture, and single manual control of the mechanical oxygenation mode was chosen. To ensure safety, an extensive over-anaerobic mode was used, but the security was still difficult to improve. Human resources and electricity were wasted. A new type of automatic oxygen enrichment model was proposed, which utilized a biofan to improve the water quality and increase oxygen in the case of an emergency. The biofan was driven by solar battery, which circulated water day and night. It not only released the harmful substances in the bottom water body, but also greatly improved the dissolved oxygen content of the whole water body through the photosynthesis of the algae in the water body. It led to a significant reduction in the impeller aerator time to oxygen. Through the comparison test, it was found that the variation of dissolved oxygen concentration in automatic control mode was less than that in single oxygenation model in 24h. By measuring and analyzing the dissolved oxygen content at 0.6m and 1.0m below the water, it can be seen that the difference of dissolved oxygen content in the upper and lower layers in automatic control mode was smaller than that in the single control mode. It was mainly because the upper and lower water bodies continued to cycle in automatic control mode. The concentration of dissolved oxygen in water was monitored by ZigBee wireless sensor network in real time. When the dissolved oxygen concentration was lower than the set lower limit, impeller aerator was automatically activated, and when it was higher than the set upper limit, impeller aerator was stopped to achieve the purpose of accurate oxygen.Incremental PID control mode was adopted.

Abstract:In order to expand the oxygenation range of fish ponds, improve oxygenous efficiency, ameliorate the water environment and save energy, the solar-powered walking intelligence robot was developed. The robot can walk intelligently and stir the upper and lower layers of water for oxygenation, which was suitable for 2666~5333m2 of fish ponds for auxiliary oxygenation. The robot was developed based on HF-LPB100 ultra low power embedded WiFi module exchanges data with the whole system, the solar panels provided electrical energy, besides, ultrasonic distance measurement module was used to avoid obstacles, the ultrasonic depth finder prevented the robot stranding, and there were two modes designed for the robot: automatic mode and manual mode. In the manual mode, the moving direction of robot was decided by remote control from the user for oxygenation. In the automatic mode, Z-type finite state mode was chosen in the path planning, which was based on ant colony algorithm. STM8L051F3P6 was used as core to control the electric motors, and PWM generated a square wave that decided L9110’s level to control the differential speed of double motors. The results showed that the path of the robot can reach more than 23.17% of the area, and the oxygen increasing range was 15.4% greater than that of the traditional aerator, and the oxygenation capacity was 1.69kg/h.

Abstract:K value is an important freshness index. It indicates nucleotide degradation, which is usually employed to assess meat spoilage. High-performance liquid chromatography (HPLC) is a common analytical method to estimate K value. However, it is time-consuming, destructive, and is not suitable to monitor pork freshness rapidly, non-invasively and in real-time. The feasibility of Terahertz (THz) spectroscopy in predicting K value of pork non-destructively was studied. The THz spectra (0.2~2THz) of 80 pork samples with different freshness in the attenuated total reflectance (ATR) mode were acquired. Their K values were also measured by HPLC. Three models were established to predict K value, such as principal component regression (PCR), partial least squares regression (PLSR), and back propagation artificial neural network (BP-ANN) after the sample spectra were preprocessed by the first order derivative and filtered smoothly by Savitzky-Golay. Comparative research results showed that the nonlinear algorithm model of BP-ANN was the most superior way among three models whose root mean square error of prediction (RMSEP) was 14.36% and correlation coefficient (RP) was 0.75 in the prediction set. The THz spectral combined with BP-ANN model can be used to predict pork K value although it was not perfect. Compared with HPLC, the THz spectral was non-destructive, rapid and simple. The research would lay a theoretical foundation for developing portable THz inspection equipment based on the THz spectroscopy.

Abstract:Organic acids are one of the important flavoring materials and functional compounds in wines. A new method for determining the content of seven kinds of organic acids simultaneously in wines with high performance liquid chromatography (HPLC) was established. Using this method, all seven organic acids were successfully separated. The method showed good linear relationship, precision and repeatability. Using this method to analyze the varietal wine and vintage wine, results showed that variety and vintage both had significant influence on organic acids in both red and white wines, in which variety played a greater effect than vintage. In red wines, the main organic acids were tartaric acid and lactic acid, while the citric acid content was very low. Meanwhile, in white wines, which was different from red wines, the main organic acids were citric acid and malic acid, followed by tartaric acid. Furthermore, this method was used to analyze the organic acids quality condition in Beijing market wines. The results also showed that the overall quality condition in Beijing market wines was good. Only five samples among 103 wine samples were found with an overdose of citric acid, with a relevance ratio of 4.9%. It could be effective to distinguish wine from other wine according to organic acid content. Citric acid content and the scale value of citric acid on whole organic acids could be used to preliminary detect fake wines, especially these fake wines using alcohol, essence, saccharin and water. What’s more, organic acid characteristics were different between imported wine and domestic wine, wines from different regions, wines from different wineries.

Abstract:AMR (antibiotic mycelial residue) added to animal feed easily leads to drug resistance influencing human health and environment. However, there is a lack of effective detection methods, especially fast and convenient detection technology, to distinguish AMR from animal feed. In order to search effective detection methods, qualitative discriminant analysis of soybean meal and antibiotic residue was made at first. The feasibility of near infrared micro-imaging for the identification of soybean meal and antibiotic mycelial residues was explored. Three soybean meal samples and three kinds of antibiotic mycelial residues were used to collect the near-infrared microscopic images of the samples by Fourier transform near-infrared microscopy. The near-infrared microscopic images collected were reconstructed and the spectra of all the samples were pretreated. The Duplex algorithm was employed to screen the representative spectra from pretreatment spectra of different samples to establish spectral library of soybean meal and antibiotic mycelial residues. Different discriminant models of soybean meal and different kinds of antibiotic mycelial residues were built by using different pretreatment methods combined with PLS-DA（partial least squares discriminant analysis）and SVM-DA (support vector machine discriminant analysis). The results showed that two kinds of modeling methods based on near-infrared micro-imaging spectroscopy were effective in the identification of three kinds of antibiotic mycelial residues and soybean meal samples, and the correctness rate was above 99.4%. The first-order derivative + SNV preprocessing method was better than that without preprocessing, the first derivative and the second derivative. SVM-DA model was superior to PLS-DA, and SVM-DA in feature extraction method was better than PCA (principal component analysis). The results presented indicated that the near infrared microscopic imaging technique can be used to qualitatively distinguish antibiotic mycelial residue from soybean meal, and it also provided theoretical basis for further research.

Abstract:In order to improve the safety of intelligent vehicle in sudden traffic dangerous condition, a humanoid intelligent decision-planning algorithm was designed for active braking system. The characteristics of braking deceleration of experienced drivers under sudden traffic hazard were simulated and the target current function Ii-hope of the braking motor under the condition of different maximum tire-road friction coefficient was established. According to the actual slip ratio λ and the maximum tire-road friction coefficient μ in the braking process, a real-time decision-planning was made for the optimal target current of the braking motor. Using CarSim’s vehicle model, a humanoid intelligent decision-planning algorithm of active braking system was built in Simulink. Through the joint simulation of CarSim and Simulink and compared with the hydraulic brake system that existed in CarSim, the braking performance of stationary target and moving target under different tire-road friction coefficients was analyzed. The results showed that in the sudden danger of traffic conditions, the designed humanoid intelligent decision-planning algorithm was able to control the slip ratio in the current road near optimal slip ratio, and when taking both comfort and safety into consideration, the braking ability of the active braking system was increased by 4.12%~4.38%, which effectively reduced the accident rate of intelligent vehicle under the dangerous traffic condition.

Abstract:During the hydraulic control unit of ESC (electronic stability control) working process, the main function of the solenoid valve is to adjust the wheel cylinder pressure precisely. However, the linear control mode which can not maintain consistency of control accuracy is susceptible to the state of the hydraulic brake system and the working environment of the solenoid valve, therefore, the stepped decompression control method was proposed, and control parameters were calibrated to realize the precise decompression control. Based on the analysis of the hydraulic valve spool force and hydraulic response characteristics of solenoid valve, it was pointed out that the pressure change rate can be obtained by adjusting pressure control status and duration time of the signal state of solenoid valve to provide basis for the realization of stepped decompression control. The pressure control state of solenoid valve adopted the delay opening and closing control method, which can avoid the frequent switching of the pressure control state between the decompression state and the holding pressure state. The duration time of the solenoid valve control signal state was affected by the pressure change rate and the switching delay phenomenon, in which the flow rate coefficient of the valve port affected the pressure change rate, the opening delay time and the closing delay time affected the switching delay phenomenon were calibrated by the test. With the help of a test bench, different pressure increase rates were tested when the cylinder hydraulic pressure was decreased. Results show that the proposed stepped decompression control method can make the cylinder pressure follow the target pressure well and the bias of experiment data can be maintained within 1MPa. At the same time, the control method had high control precision.

Abstract:A new four-degree-of-freedom (4-DOF) parallel manipulator that can produce 3-DOF translations and 1-DOF rotation was proposed. It had two identical limbs connected to the moving platform through passive revolute joints, and each limb had two identical branches driven by a pair of base mounted collinear prismatic joints. Due to such a simple and symmtrical kinematic structure, the 4-DOF parallel manipulator had the advantages of simple kinematics, large workspace, high speed, high positioning accuracy and easy processing. These advantages made it an appropriate candidate for high-speed and high-precision sorting, pick-and-place, palletizing and assembling operations. Compared with similar parallel manipulator, it showed a unique advantage in long-distance high-speed operations. Firstly, the configuration of 4PPa-2PaR parallel manipulator was introduced, the simplified mathematical model of the mechanism was established, the number and nature of mobility were verified with screw theory and the modified Grübler-Kutzbach criterion, and the kinematic characteristics was studied. Secondly, the workspace was determined by a numerical method, the influence of each design parameter on the workspace was analyzed, and the workspace shape and geometric constraint condition were discussed by analytic method in detail. Finally, the ratio of workspace to parallel mechanism itself was determined as the objective function, the design constraints, such as boundary constraints, non-interference constraints, singularity avoidance constraints and workspace shape constrains, were established and genetic algorithm was selected to optimize the size parameters. The results showed that the ratio of workspace to parallel mechanism itself and workspace volume after optimization were significantly increased, and the optimization results provided important guidance for the subsequent prototype development.

Abstract:Aiming at the present situation that forward kinematics of most 6-DOF (degrees of freedom) parallel mechanisms cannot be described with whole analytical solutions, and a very few of them can be described with whole analytical solutions but also with these difficulties, including calculation, programming, and sorting the suitable solution, a general 12-6 Stewart redundant parallel mechanism with hybrid single opened chains was presented, and a whole analytical decoupling algorithm of forward kinematics, which was needed by the closed-loop real-time feedback control system, was constructed. By calculating the position and orientation characteristics set and decomposing the routes of single opened chains, the topological configuration of new mechanism was analyzed, and then the coupling degrees was solved, which were useful to show clearly direction to construct and process the kinematics equations. Based on the topological relations between four coplanar feature points on the moving platform, the combination algorithms of 15 quadratic isomorphic compatible equations were designed, and then the whole analytical solution, which was succinct, symmetric and unique, of forward displacement equations was derived. Based on the method of base points, velocity relations between feature points were established, and then forward velocity equations were solved. Based on compatibility equations and velocity equations, the Jacobian matrix of mechanism was derived, and then three types of singular equations were also derived. Experimental results indicated that the calculated values of forward displacement equations were well consistent with the measured values, and calculation error of forward velocity equations was 0.08%, and the calculation/sampling time ratios of these two equations were 0.21 and 0.32, respectively, which met the real-time demand of control algorithms.

Abstract:A novel 2SPU+U+RRR 5-DOF hybrid mechanism with one 2-DOF parallel mechanism and one 3-DOF serial mechanism was presented. This 5-DOF hybrid mechanism had advantages of large workspace and high stiffness compared with traditional hybrid mechanism. A prototype of this hybrid mechanism was constructed and it was equivalent to a U+RRR parallel mechanism, the analytic formulas for solving its inverse/forward displacement kinematics were derived and the forward displacement was derived based on D-H method. The unique solution of the inverse kinematics was determined based on the shortest distance rule, and the correctness of the analytical expression of the inverse/forward displacement kinematics was verified. The length of the two SPU active legs were derived based on the rotation angle of the Hooke hinge, thus the analytic formulas for solving the inverse displacement kinematics of the 2-DOF parallel mechanism was derived. Theoretical kinematics formulas and results provided foundation for the control of the hybrid mechanism, structure optimization design, dynamics performance analysis, manufacturing and applications and the study also enriches the application area of lower-mobility parallel mechanisms. A novel interpolation algorithm for an arc based on equal radian data sampling was derived, the calculation of interpolation algorithm was greatly simplified. In order to verify the correctness of the interpolation algorithm for an arc, the experimental prototype and its control system were built. The simulation result by Matlab and the experimental prototype result showed that the interpolation algorithm for an arc was correctness and this algorithm had great application prospect.

Abstract:Aiming at the question of the dynamic of linear driven parallel robot, based on the geometric structure model of linear driven parallel robot, the kinematics model of linear driven parallel robot was established by using the vector method. The inverse kinematics model, velocity and acceleration model of the linear driven parallel robot was obtained based on the d’Alembert’s form of the principle of virtual work, each actuated torque of the mechanical system moving parts were analyzed with a virture displacement. The dynamic equation was derived and the affecting factors of the linear driven parallel robot was determined. By a given trajectory of the moving platform, the torque of the motors was derived by the back solution, the inertia term which was the most important factor of the torque was analyzed. By a conical spiral trajectory, through the combined simulation model of Matlab and ADAMS with the test of load characteristic, the test curve was compared with the theoretical curve of electrical motors torque, which can verify the correctness of the dynamic theoretical model and the theoretical dynamic equation, which made the foundation of optimization of dimensional synthesis and trajectory planning of linear driven parallel robot and also gave the theoretical support for the research and development of the similar parallel robot.

Abstract:Novel electro-hydraulic servo valves (EHSVs) usually require their actuators output large stroke bi-directionally. To meet these requirements, a special stack giant magnetostrictive actuator amplified by flexure hinge (FASGMA) was designed, the displacement model of this actuator was established, and experiments were conducted to verify the model. Firstly, considering the ways to provide bias magnetic field in traditional GMA, a specific structure, with permanent magnets (PMs) and short GMM rods located iteratively, was designed, whose output was amplified by a bridge-type flexure hinge. Then, based on the structure, a strain model of SGMA was established, which can describe the strain distribution along the GMM rod. In addition, the amplification ratio and eigenfrequency of the flexure hinge were analyzed by basic theories of mechanics and finite element method. Meanwhile, with an optimization design method proposed, the structural parameters of the amplifier were decided. Moreover, a multi-DOF displacement model of FASGMA was set up, which considered the interaction of flexure hinge and SGMA as well as the strain distribution along the axial direction of SGMA. After that, the number of DOF was determined. Finally, an experimental system was established, and the proposed model was verified by both step and sinusoidal experiments. The results indicated that when the FASGMA was excited by step signals, the maximum output displacement was about 130μm, the response time was about 70ms. Under harmonic excitation, the frequency bandwidth was about 60Hz and the actuator performed a good tracking behavior with the excitation signal.