Abstract:The operation principle of a burner-type diesel particulate filter was presented. Taking the subordinate oxidation reaction model into consideration, and taking the honeycomb wall-flow ceramic monolith filter as a research object, the simplified regeneration model in the single inlet channel of the filter was built at the steady state of the diesel engine. Based on the non-dimensionalization and the exhaust back-pressure model of DPF, the required temperature condition of the inlet exhaust for the burner-type DPF was obtained. The tests showed that the DPF regeneration could be smoothly completed by the burner power adjustment according to the oil spray rate correspond to the theoretical inlet exhaust temperature. It provided a definite theory basis to the design of the burner-type DPF.

Abstract:Estimating combustion timing in diesel engine by cylinder head vibration acceleration was presented. The correlation between the vibration acceleration and the second derivative pressure was compared based on a 195 diesel engine finite element model. Results showed that the vibration acceleration and the second derivative pressure had the similar trend before the peak pressure, and the combustion timing was supposed to be identified by the zero vibration acceleration at this range. Experiments were conducted on a 195 diesel engine and the results verified that the combustion timing could be determined by the vibration acceleration of cylinder head with the deviation within ±1.5°CA.

Abstract:Performance of the LNG (liquefied natural gas) engine was tested on overall conditions at four different coolant temperatures, the temperatures were set at 60℃, 70℃, 80℃ and 90℃ in the tests. The testing results showed that coolant temperature influenced on performance of the LNG engine, the higher coolant temperature was, the better fuel economy would be, but NOxemission would be more. The coolant temperature also influenced on HC and CO emissions, but the influence was not obvious. By doing the tests, the optimum coolant temperature MAP of the engine was obtained.

Abstract:DME and hydrogen were blended with air in intake and the HCCI combustion was realized. The speed of engine was hold at 1400r/min and the mass flow rate of DME was ranged at 2.6 and 3.5L/min. With the hydrogen fraction increasing, the excessive air coefficient λ was reduced until the engine knocked. The result showed that DME blended with hydrogen could increase the peak pressure, heat release rate and BMEP. The peak pressure was improved 26.4% when the DME flow was 3.5L/min. In the emissions, CO and HC could be reduced, and CO emission was only 20%~30% of the original data after hydrogen enriched. However, NOx emissions increased with the addition of hydrogen.

Abstract:The spray characteristics of pressureswirl nozzle used in Stirling engine was studied by way of the experiment under high ambient pressures (up to 2.8MPa). The highspeed video imaging technique, FAM (Fraunhofer and Mie) laser drop size analyzer, and PIV (particle image velocimetry) test equipment were used for experimental measurements. Experimental results showed that the spray structure at higher ambient pressure was more compact. The vortex cloud was found at the leading edge at high ambient pressure. Spray cone angle was independent of ambient pressure after a value between 1.0~1.5MPa. The Sauter mean diameter (SMD) and the drop velocity became larger at high ambient pressure conditions. Finally, a vortex was found in the center of the spray and this region moved to the downstream of the spray as the ambient pressure increased.

Abstract:Electrostatic atomization phenomenon for single droplet was shot based on high-speed video camera with tens of thousands of frames per second. The deformation of the charged and non-charged droplets, as well as their movements were compared and analyzed. The atomization mode at different voltages and the Taylor-cone length and cone angle changes under cone-jet mode were obtained. The results showed that droplet size decreased when the voltage increased, whereas its velocity increased with the voltage increasing. Biodiesel has bigger deformation rate than water under the same capillary, and the small droplet of biodiesel has larger deformation degree than big one. As the voltage increased, droplet went through dripping mode, the transition phase, cone-jet mode and multi-jet mode. In cone-jet mode, the cone length of Taylor-cone became direct ratio to the voltage, whereas the cone angle inversed to it. Conductivity had impact on the droplet movement, droplets with smaller conductivity moved along with the capillary axis, while droplets with bigger conductivity had both axial movement and radial movement.

Abstract:According to the operating characteristics of wheel loaders, the energy distribution and saving potential of loader were researched through calculation and simulation. Combing the characteristics of hydraulic hybrid system, the parallel configuration of hydraulic hybrid wheel loader was presented, and the influencing factors for hydraulic hybrid wheel loader energysaving potential were analyzed. Finally, the key parameters were optimized. The results show that optimization of hydraulic hybrid power system, selection of the appropriate parameters in control strategy, recovering the braking energy and long slope potential energy of loaders are helpful to improve the energy saving effect of hydraulic hybrid loader.

Abstract:The Qiaozi-East watershed with management and QiaoziWest watershed without management at the third sub-region of Loess Plateau were selected as studying areas. The rainfall, runoff and sediment data were used to study the effects of soil and water conservation management on sediment yields, runoffsedimentation relations, and sediment delivery processes. The annual sediment yields of Qiaozi-East watershed were considerably lower than those of Qiaozi-West watershed. The mean sediment contents in runoff and mean sediment delivery rates from Qiaozi-East watershed were 40% and 80% less than those from Qiaozi-West watershed respectively. Soil and water conservation management altered the sediment contents and sediment delivery processes. At the early stage of the practice, the sediment contents from Qiaozi-East watershed were higher than those of Qiaozi-West watershed, but the sediment delivery rates were more or less than those of Qiaozi-West watershed. With years of management, the sediment contents and sediment delivery rates from Qiaozi-East watershed were lower than those from Qiaozi-West watershed. Soil and water conservation management altered the runoff and sediment relations.

Abstract:In order to describe the relationship between soil particle size distribution and soil physical properties, the parameters of soil particle size distribution, soil bulk density and soil saturated hydraulic conductivity were measured, and the heterogeneity of soil particle size distribution was characterized by the parameters of multifractal spectrum, and then the relationship between multifractal parameters of soil particle size distribution and soil bulk density, soil saturated hydraulic conductivity were discussed. The results showed that the heterogeneity of soil particle size distribution could be reflected by the multifractal parameters of soil particle size distribution such as D1/D0 and Δα , the multifractal parameters were closely related with soil clay content, and when the soil heterogeneity is larger, the soil clay content is higher, and that results in soil bulk density increasing, soil saturated hydraulic conductivity decreasing. Therefore, the multifractal parameters of soil parameters can be used as an indicator to reflect the soil physical properties.

Abstract:Based on the theory of unsaturated soil water dynamics, the soil water distribution under vertical line source infiltration was analyzed by the software Hydrus-2D. The model was testified by the experiments and soil hydraulic parameters were estimated. The result showed that this model could be used to simulate soil water infiltration characteristics with certain accuracy. The characteristics of water distribution under line source irrigation were simulated concerning different irrigation technique factors. The results showed that, under the condition of line source irrigation, the shape of wetting patterns under different soil textures was similar, and the scale was different: the ratio between the maximum sand loam and clay loam’s level wetting radius and sand’s were 0.59 and 0.24, the ratios of vertical humid depth were 0.42 and 0.31; on the condition of different line source depth, the shape and scale of wetting patterns were similar, and the positions had great difference, when the depth increased 5cm, the vertical humid depths of sand, sandy loam and clay loam were increasing by 6%, 11.5%, 16% separately; the length and the diameter of the line source had conspicuous influence on soil water distribution, the length had a major impact on the vertical humid depth, the diameter had a primary influence on horizontal wetting radius; when the initial water Symbol`content was high, the water content in the same cross-section increased; in the same period of irrigation time, the wetting front distance of level and vertical increased with the increasing of initial water content. 

Abstract:In order to seek the variations of soil water repellency and its relationship with soil moisture content, soil salt content and pH value, soils samples were collected in two profiles at two grids (intervals were 10cm×10cm and 5cm×5cm, respectively) in a newly cultivated cotton field mulched with plastic film and irrigated with trickle method in Xinjiang. The soil water repellency, soil moisture content, soil salt content and pH value of the profiles were tested and analyzed using the methods of classical statistics, geostatistics and correlation analysis. The results showed that the soil water repellency had moderate variability and the spatial autocorrelation was under the level of the middle class in secondary saline field profiles. The strongest soil water repellency appeared around the depth of 40cm and the characteristics of soil water repellency were not obvious when the depth was deeper than 80cm. The soil moisture content and the soil water repellency appeared to be positively related at 0~40cm depth and negatively related at 40~80cm depth. Soil salt content and soil water repellency appeared to be positively related to the surface soil layer at 0~10cm depth but negatively related to the other depth. The pH value and the soil water repellency mostly were generally positively related. 

Abstract:Exploratory research on the optimization of transplanting mechanism, which is the key working component of the rice transplanter, three methods to establish the theoretical models have been proposed. In the process of building models, circuit simulation method is applied to solve the elastic dynamic problems which are caused by impact loads. As to the process of fetching seedlings which is difficult to build models by using theoretical deduction, firstly establish the numerical model by test measurement, then inlay this numerical model into the general theoretical model. The reliability of the general theoretical model is proved by measuring bearing force of transplanting mechanism in the testbed experiment. Through highspeed camera, the relation between the motion of seedlingpushing rod and the rotation angle of planet carrier can be measured, and this relation can prove the correctness of differential equations of seedlingpushing mechanism. A method that can solve the complicated multiple object optimization problems which are strong coupled, dizzy and nonlinear has been proposed. Its called the method of optimization guided by parameters modification. And the theoretical model of this method has been established. A software with functions of optimization, virtual manufacture, virtual trial and test has been compiled basing on VB platform. The function of parameters modification guiding optimization has been added to this software on the foundation of numeralization of the objective function.

Abstract:In order to predict the performance of deep-well centrifugal pump quickly and accurately by the commercial CFD software Fluent, 150QJ20 type deepwell centrifugal pump was taken as an experimental object to research the key set methods on the Fluent simulation. The numerical simulation was carried out at different grid numbers, different residual convergence precisions, different turbulence models, and different flow calculation methods to analyze the impact on simulation results. And different stages of the deep-well centrifugal pump model simulations were analyzed and discussed. The best set methods of numerical simulation for deep-well centrifugal pump were selected. The differences between numerical simulation and experimental results were compared and analyzed. This work is real significance in understanding the accuracy for deep-well centrifugal pump, and it confirmed the feasibility of predict the performance of deep-well centrifugal pump by using Fluent.

Abstract:Based on the Navier-Stokes equations and the Spalart-Allmaras turbulence model, 3-D turbulent flow field in centrifugal pump with longmidshort blade complex impeller was calculated and analyzed numerically. The relative velocity and pressure distributions in the flowpart were obtained. It was found that the flow in the channel of the complex impeller was unsymmetrical due to the joint action between the volute and impeller. The flow in other channels was similar to that calculated using the single channel except for the ones near the volute throat. The backflow region was at inlet of longblade suction side, near middle part of longblade pressure side and outlet of shortblade suction side. The flow near volute throat was affected greatly by volute. The relative velocity was biggish and it was easy to bring back flow at outlet of the complex impeller near volute throat. And the static and total pressure rose uniformly from inlet to outlet in the impeller. The flow from the impeller outlet to volute had a trend to form the swirl near the wall of the volute and moved forward in spiral direction.

Abstract:The cause for the generation of prerotation and recirculation in the suction chamber was analyzed and the two-sided effect of prerotation on the hydraulic performance in centrifugal pump was pointed out. The effective solution was baffles built in suction chamber. With different physical parameters and placement of the baffles in suction chamber, CFD numerical simulation was applied to predict the performance variation trend of centrifugal pump. According to the performance curve and the flow state in the chamber, the optimum baffle came out: the radial length is D0 /4 (inlet diameter), and the 3/4 length of chamber is the value of axial length for the baffle. And, two baffles should be put closed by the impeller. The prototype was designed for hydraulic modeling test. The result indicated that the performance of the new model is superior to the original one. The values of head and efficiency rose by 0.8m and 1.7% at the design condition, relatively. Fluent numerical simulation with high accuracy could be applied in structural optimal design of centrifugal pump. 

Abstract:A mixed-flow pumping system was selected as the study case based on CFD technologies. Two difference methodologies of flow field analysis and performance prediction were conducted. One method was that the system efficiency was the production of pump efficiency with passage efficiency obtained by separate numerical simulation of suction box and discharge passage without pump. The other one was based on the simulation of whole pumping system including the suction box, discharge passage and pump. The predicted results from the two different methodologies were compared with model system test results, which showed that the predicted errors were different. The error of pumping system efficiency was smaller when the numerical simulation of whole pumping system was adopted, while the error was much greater when the system efficiency was predicted by the production of passage efficiency with pump efficiency, approximately equal only near the best efficiency point. The larger errors in predicting pumping system efficiency for the first method were mainly caused by unreasonable theoretic foundation. Therefore, it is suggested that the suction box, discharge passage and pump should be taken as a whole in numerical simulation and performance prediction and the effect of pump should be considered in the optimal hydraulic design of suction box and discharge passage. 

Abstract:PXSB two-ways step running complete fluidic rain gun is a new type of large-middle rotary sprinkler. The key component of the sprinkler, fluidic element, provides the driving force and controls the movement of the sprinkler based on Coanda effect. Hydraulic performance of the rain gun was tested. The main influencing factors to the range, height and rainfall distribution were analyzed. The influences of the working pressure and the structure parameters on the main hydraulic performance of the rain gun under its working states have been obtained by the experiments. The best geometrical size was achieved at the experiments, which provided a basis in building the design method of the twoways step running complete fluidic rain gun. A comparison of hydraulic performance was made between the complete fluidic rain gun and the other largemiddle rotary sprinkler. According to the results, the twoways step running complete fluidic rain gun has better performance than the others. 

Abstract:To study the performance of wastewatertreatment mixer because of its large application in the rural environmental governance, based on CFD, using Fluent 6.3, wastewater treatment mixer with dome was simulated. At the same time, the velocity flow field distribution in the wastewater treatment pool was experimentally studied, and the fluid velocity at the different points of the pool was measured by using the velocity instrument. The velocity distribution graphs of the different sections in the wastewater treatment pool were drawn by software Excel, and the velocity distribution rule was analyzed. The same results were obtained by the numerical simulation and experiment. The fluid flow obviously transferred along the axial direction of wastewater-treatment mixer but little diffused along the radial direction, and fluid velocity symmetrical along the mixer axis. The results indicate that the wastewater-treatment mixer can guide flow in axial direction, and can reduce the effect of boundary of pool wall on the fluid in pool. 

Abstract:Biomass gasification with steamoxygen enriched air in an atmospheric fluidized bed gasifier was studied. The gasifier was 9m high with the bed diameter of 0.5m. Sawdust with different moisture contents was used as feedstock, and it was fed into the gasifier at flow rates of 180～270kg/h. The effects of equivalence ratio, steam to biomass ratio, secondary flow ratio and feedstock moisture on the bed temperature, gas compositions, tar content, lower heating values, gas yield, carbon conversion efficiency and cold gas efficiency were investigated. The results showed under the operating conditions of ER is 0.25～0.27 and S/B=0.4, the following syngas was obtained: H2 content of 28.7%, H2/CO ratio of 0.94, low heating value of 9.9MJ/m3, cold gas efficiency was more than 75%, carbon conversion efficiency was more than 97%; a second flow ratio of 25% at the ER of 0.29 can significantly reduce the tar content to 49mg/m3, but hardly improve the quality of the gas produced; the rise of the feedstock moisture content caused a significant increase in CO2 content and a reduction in H2 and CO contents, and the moisture content is expected not to exceed 20%. 

Abstract:Factors that affect the corn densification contained pressure, heating temperature, moisture content and etc., and microstructure of briquette also has a major impact on the macroscopic properties. The microstructure and binding mode of material particles inside briquette were observed with electron stereoscopic microscope, the relationship between molding process parameters and forming microstructure were studied from the microscopic view. The results showed that particles in corn straw briquette were mainly combined in two forms—mechanical mosaic and natural adhesive bonding. Under the condition of pressure 60~90MPa, material temperature 75~100 ℃, moisture content 8%~16%, internal particles of briquette were combined closely, with obvious mechanical enchase effect, corresponding to get physical quality and mechanics with good performance. 

Abstract:In order to transform a large number of abandoned sugarcane leaves into biogas energy, dry anaerobic fermentation method and the fermented materials with total solid content of 20% were used in the experiments. The effects of different inoculum concentrations, grassmanure ratios and fermentation temperatures on the biogas yield and methane content were analyzed. Results showed that the fermentation could work normally when inoculum concentration was 30% and 40%. The 40% inoculum concentration had the highest total gas production, but the methane content decreased rapidly during the fermentation anaphase. When grassmanure ratio was 1∶1 and 2∶1, maximum total gas production was obtained, with methane content more than 60%, and the gas production efficiency was significantly higher than the efficiency obtained when grassmanure ratio was 1∶0. Maximum total gas production and methane content were obtained at the fermentation temperature of 35℃. There was little difference in total gas production when the fermentation temperature was at 30℃ and 40℃. The best results of dry anaerobic fermentation of sugarcane leaves were obtained for an optimum processing parameters combination of 30% inoculum concentration, 1∶1 grassmanure ratio and 35℃ fermentation temperature. For all the treatment groups, there was a strong linear correlation between methane content and fermentation time before the methane content reached the highest value. The decrease in methane content was not obvious though the daily biogas yields decreased significantly after the peak of gas production.

Abstract:In order to further understand the frequency of Helmholtz pulse combustor, a Helmholtz type combustor was used to carry out the experiments in conditions of different gas flow rates. Through the experiments of three lengths tail pipe, frequency was all increased while the gas flow rate increased. The impact of gas flow rate on frequency was investigated, and the modification of theoretic formula was also proposed based on the difference between the theoretical and actual values. Compared with the experimental values, the results showed that the predicted values and the experimental values matched well.

Abstract:An experimental device of ventilation system was established to meet the requirement of freshkeeping transportation with controlled atmosphere by liquid nitrogen. The pressure drop characteristics of the ventilation system were studied. The effects of airflow velocity, ratio of open area, stack mode and length of return air channel on the characteristics of pressure drop and energy consumption were analyzed. The pressure drop characteristics could be described by the equation of Ramsin. The pressure drop increased with the addition of airflow velocity. At the same airflow velocity, the pressure drop decreased with the addition of ratio of open area. The distribution of pressure drop in freshkeeping room was steady. The effect of three stack modes on the pressure drop was not striking. The pressure drop was less when there was no return air channel. When the ratio of open area of the separator with holes in freshkeeping transportation vehicle was bigger than 3.89%, it could meet low pressure loss and had small energy consumption. The research achievements will be instructive to the design of the ventilation system in freshkeeping transportation with controlled atmosphere. 

Abstract:In view of the main packing form and damage of cherry tomatoes in storage and transportation process in nowadays, the main reasons for the damage of cherry tomatoes package were studied. By choosing a kind of typical cherry tomato packages in the circulation market, five real tests, which included sinusoidal vibration test at variable frequency, vertical impact and dropping tests as well as stacking strength test and vibration transmissibility of multipackages stacking test, were carried out according to the national test standards. Through sinusoidal vibration test at variable frequency on the single layer package and stacking strength test, the resonance frequency and maximal stacking layers were determined respectively: the natural frequency of a single package was 26.61Hz and the maximal stacking layer was 9. Then, the natural frequencies of every layer package were determined by 9 stacking layers vibration transmissibility experiment at variable frequency, and they were 36.61, 10.76 and 6.44Hz for the bottom, middle and top layers respectively. Curves of acceleration and vibration transmissibility of every layer package vs time were obtained. The relationships of its natural frequency and peak value of vibration transmissibility vs stack height were discussed. On the basis of the above, the fragility of each package was 89.58 by carrying out the vertical impact test. Also, the allowable maximal dropping height is 580mm according to the dropping test. Finally, the protection capability of the packages on cherry tomatoes was evaluated and some suggestions were also given.

Abstract:The effects of chitosan coatings on the control of superficial scald in “Fuji” apples were investigated, and the dynamic changes in αfarnesene production and oxidation, the texture and function of cell membrane and the activity of enzyme related with browning were also measured to reveal the mechanism of chitosan coatings in the superficial scald control. The results indicated that by chitosan coatings, the respiration rate and the ethylene production were inhibited, the production of αfarnesene and the accumulation of conjugated trienes were reduced, membrane lipid peroxidation was weakened and the integrity of cell membrane was kept, and the increase of polyphenoloxidase (PPO) activities was inhibited, the chitosan coating could effectively control the superficial scald in apples.

Abstract:A fruit and vegetable infrared drying online realtime detecting system was designed. Using the quality sensor, the AD temperature sensor, the PCI8310 data acquisition card and so on, the data of fruits and vegetables in the drying equipment were stored in PC. These data were processed and visualized by the program written by the Visual Basic, and then, drying curves, radiation temperature variation curves and material temperature variation curves were generated. The detecting experiment results showed that the online detection error was within ±003% and the characteristics were displayed accurately and timely. 

Abstract:The hyperspectral imaging technology was used to detect the bruises and solid soluble content (SSC) of apples simultaneously. The image at 794nm from the first principle component was subtracted, the series of denoising and threshold processing were performed and the bruises on apples were predicted with the accuracy of 92.6%. In the hyperspectral imaging, region of interest (ROI) was determined and spectrum reference curve was calculated. The original reflectance spectrum curve was processed by multiplicative scatter correction (MSC), a first derivative and Savitzky-Golay (SG) smoothing, and PLSR model was developed to predict SSC with Rc of 0.93, SEC of 0.47°Brix, and Rv of 0.92, SEV of 0.67°Brix. The research showed that it was feasible to detect the SSC and bruises on apples simultaneously with hyperspectral imaging technology.

Abstract:In order to explore a non-destructive method in identifying kiwifruit ripeness, a near infrared diffused spectroscopy technology was used to determine firmness of Huayou kiwifruits during cool storage. Partial least squares (PLS) regression was carried out to analyze the spectroscopy. Four different spectral pretreatment methods were used to compare calibration results for firmness. The result showed that the best calibration models, in the whole wavelength range, could be obtained by the first derivative spectrum with the correlation coefficient of calibration of 0.963 and the correlation coefficient of prediction of 0.852. 

Abstract:Immobilized cellulase was pretreated by ultrasound. Based on the single factor and response surface methodology, the effects of ultrasonic parameters, such as ultrasonic time, ultrasonic frequency and ultrasonic power, as well as enzymolytic temperature and pH value of CMC-Na buffer solution after pretreated were investigated. A mathematical model was established and analyzed to describe the relationships between the studied factors and enzyme activity. The optimum treatment parameters were as follows: enzymolytic temperature of 58.73℃, pH value of CMC-Na buffer solution of 3.0, ultrasonic time of 16.88min, ultrasonic frequency of 22.33kHz and ultrasonic power of 26.77W. Under the optimum conditions, enzyme activity of immobilized cellulose increased by 9.75%.

Abstract:The effect of different milling pH value on cheese meltability was studied. Combined with confocal laser scanning spectroscopy, DSC and rheometer techniques, meltability, freezable water content, pH 4.6soluble protein and UreaPAGE were analyzed during 1~7 weeks storages. Results showed that Mozzarella cheese with a low milling pH value had less freezable water and more binding water. When the storage prolonged (more than 21 d), protein degradation increased, and better meltability was achieved. 

Abstract:In view of harvesting damages and failures caused by the absence of attitude information in the current apple harvesting robot, the method of measuring apple attitude was put forward with the machine vision, and the optimal estimation of apple attitude was carried out based on the particle filter in real time. A camera was fixed on the robotic gripper, in the process of picking the camera vision field was controlled to cover the expected fruit target, and a series of apple images were sampled randomly. The algorithms of the inertial axis and the center offset were applied to calculate the apple attitude at the robotic coordinate according to the each apple image. Finally, the attitude data extracted from many apple images was fused with the particle filter, and the optimal estimation of the apple attitude was obtained. The experimental results showed that the multiple information of apple attitude was fused successfully, and the measurement error of apple attitude was decreased effectively.

Abstract:By analyzing morphological feature of tipcap of agricultural kernel, a tipcap identification algorithm based on Harris corner detector was developed. Harris algorithm detected the corner within a local region. As the most obvious corner structure, the tipcap had the maximal response to Harris corner detector, which made it can detect the kernels without the obvious tipcap accurately. The kernels with tipcap of corn, pumpkin and summer squash were selected for the test. The experimental results on 750 kernels showed that the proposed method got overall accuracy of 95.6% for tipcap of kernels.

Abstract:An extraction algorithm based on color and texture was developed to realize segmentation between downy mildew and cucumber plants in greenhouse. A light analysis model was established by comparing the distribution of cucumber images in RGB, HIS and YCbCr color space, which was beneficial to the recognition of disease in variable illuminations. Combination model of Cband Cr elements was built based on the mean difference of lesions and interference informations in Cb and Cr, which included leaves, poles and soil, and extracted target rapidly. A detecting expriment was carried out on 30 images with downy mildew, which were taken in a changing greenhouse enviornment. The results indicated that the accuracy rate of segmentation was 90.6%. 

Abstract:In order to improve the accuracy of muskmelon’s defect detection, an automatic defect detection system based on support vector machine (SVM) was set up by adopting complex features of texture and color. Four textural parameters and twelve color features of combinations from RGB were tested for the discriminability in stem, calyx, bruise and mildew. Through the experiments, two textural and four color features with good discriminability were selected and treated as the complex features. The results indicated that with the complex features and SVM, the accuracy of classification on muskmelons was up to 92.2%. 

Abstract:An improved CV model was presented according to the characters and the segmentation requirements of the remote sensing images. The correctness of the improved model was validated by the experiment. The results show that the new method can improve calculation efficiency effectively. Beside this, a continuous and closed boundary curve of the target objects can be obtained at the same time. Therefore, the land cover can be identified precisely with the help of the geometrical characteristic of the segmentation boundary.

Abstract:Based on ZigBee and GPRS, a system was designed to acquire farmland images and transfer the images wirelessly. The system consisted of MESH-type ZigBee network for image acquisition and a remote server which could communicate with the ZigBee network coordinator via GPRS network. The image acquisition based on the V4L technology was introduced first, and the process of JPEG compression and decompression was described, the method of reducing the computational complexity of image compression by the improved discrete cosine transform (DCT) was studied, then how to improve reliability in the data transmission by partitioning and checking image data was discussed. At last, the system was tested in the given field and it proved that the successful rate of farmland image acquisition was 76%. Furthermore, the difference between the theoretical and practical transmission time was analyzed.

Abstract:Based on non-destructive detection, the fluorescence spectrum of living leaves of poplar was collected by laser as excitation light source. Sensitive fluorescence spectrum band of water use efficiency was arrived through analyzing spectrum data. A model depending on the modification of leaves temperature was established. The functional relation between water use efficiency and fluorescence spectrum was described and the multiple correlation coefficients R2 were 0.975. The correlation coefficient r between calculated values and measured values was 0.8746 by verification test.

Abstract:In order to simulate the growth of plant stem, plant stem and branches were divided into fine grit, and the plant growth process was iterated by dividing the stem into tertiary structure of meristematic zone, elongation zone, maturation zone. The parametric L-systems theories were applied in simulating the geometry shape of the plant. This method can achieve a better result. For plant meristematic zone, three kinds of lateral bud factor of flower, subaxis, leaf were set to improve the controllability of different organs in plant growth. At last, the simulation experimental results showed that this method could reduce the complexity of parametric L-systems, and make the real simulation of plant’s growth process and the phenomena of botany.

Abstract:Several templates were given based on the structures and variables of a product in creativity templates. As a product has various structures and variables are determined subjectively, the multifarious and nonstandard data add to the difficulties of product innovation. Therefore a new type of product innovation method based on function incentive was put forward. Function common basis was inducted to this model. All product information was represented by the product function model systematically and normatively. Each product sub-function was operated by function dependency, function transformation, function displacement, function relocation and function random excitation strategies. Designer was assisted systematically and directionally to carry out innovative thinking. And the product creative design was realized. Finally, the design process of an agricultural knapsack sprayer was described to demonstrate this model.

Abstract:For rigid-body guidance mechanism synthesis through four finitely separated positions and four mixed positions, a displacement matrix method was presented for calculating the Burmester curves. After the equations of Burmester curves have been deduced, they were turned into the standard forms through coordinate transformations. Then according to the projective geometry theory that two pencils-of-low-order curves constituted a high-order curve, the Burmester curves could be single-valuably and orderly expressed by intersections of a pencil-of-circles and a pencil-of-lines. Finally, solution regions were set up so that the designers could have an intuitional and exact knowledge of mechanism properties.

Abstract:The mathematical model of 2D digital valve was established and its hysteresis characteristics was first simulated and analyzed. In order to diminish and even eliminate hysteresis, a dither compensation technology which used high frequency dither signal to superimpose on input signal was proposed. Then the special test rig was built and experimental study was carried out. The experimental results revealed that when dither amplitude was 25%, 50% and 100% of backlash magnitude respectively, the hysteresis width accordingly reduced from 2.2% to about 1.7%, 11% and 0.5% of backlash magnitude respectively. It is finally concluded that the proposed dither compensation approach can diminish and even eliminate hysteresis of 2D digital valve effectively.

Abstract:Scroll profile plays a key role in dynamic property of the machine. The scroll profiles were constructed by using normal-equidistant-line method based on baseline with the first-order function of radius of curvature in accordance with continuity conditions. The models of suction chamber, compressing chamber and discharge chamber were established based on the parameters of the baseline. The dynamic process of dynamic gas forces in a scroll compressor verse crank angle was obtained. The influence of the first-order curvature radius parameters on dynamic property was approached. The numerical simulation showed that the first-order curvature radius parameters of top scroll profile had significant effects on dynamic property of a scroll machine. Furthermore, the discontinuity of curvature radius of connecting point on the top first-order and involutes led to fluctuation and polarity change of radial force. Thus, the sealing forceload of radial clearance, leakage loss and bearing life would be influenced directly. 

Abstract:With the aim to improve forecasting accuracy of the normal contact stiffness of machined joints, the modified particle swarm optimizer (MPSO) algorithm was proposed. The BP neural network parameters were optimized by the MPSO algorithm. The normal contact stiffness of machined joints was forecasted under different experimental conditions, and the relative errors were analyzed. The results showed that the forecast precision could reach to 92%, and the contact stiffness of machined joints was modeled for various affecting factors. 

Abstract:On the basis of characteristic analysis for the single point incremental forming (SPIF), the problems of current study of tool-path generation for SPIF process were proposed. Based on the proposed method, a new tool-path generation method for SPIF, and the suitable Z-constant toolpath generation were presented. This method was used in the specific process planning software AFS2, and was applied to the SPIF equipment developed by the Japanese Amino Corporation, and an excellent surface quality was gained in a forming practice. Finite element analysis and application results indicate that the proposed method is feasible to meet practical needs.

Abstract:The purpose is to investigate the effects of the ultrasonic vibration on dimensional accuracy in micro milling process. Several slotmilling experiments were conducted with aluminium alloy as the workpiece material. The desired vibration was proposed from the workpiece side by an ultrasonic vibrator. The width of slot produced by end milling was precisely measured. A one-factor experiment was conducted at first to analyze the variation of slot width before and after ultrasonic vibration was applied, and the experimental results indicated that ultrasonic vibration made contribution to the decrease of size deviation and larger amplitude tends to reduce the slot width oversize. A full-factor experiment was carried out accordingly based on Taguchi method to optimize the parameters involving spindle speed, feed per tooth and vibrating amplitude. 