Abstract:3-D numerical simulation on NOx and soot emissions of 186FA diesel fueling with pure diesel and B20 fuel was carried out by using CFD software FIRE v2008, the generating rule and distribution of NOx and soot of two fuels were described. Through comparison of the measured indicator diagram, the accuracy of the model was verified. Based on the simulation of the original diesel engine fueling with B20, the swirl ratio and injection advance angle were optimized and the technical programs were proposed to reduce two kinds of emissions simultaneously, which optimized the emissions of NOx and soot when the swirl ratio was 2.7 and injection advance angle was 352.5°.

Abstract:The new petroleum coke slurry fuel system was adopted in a R180 diesel engine, and an investigation was carried out in the modified diesel engine with fuel of petroleum coke slurry. The speed, torque, specific fuel consumption, exhaust gas temperature, and HC, CO, NOx , smoke emission concentrations of the engine with fuel of petroleum coke slurry were measured respectively, and the comparison to the engine with fuel of No.0 diesel fuel was made. The results show that under the conditions of 1200, 1600, 1800 r/min and burning petroleum coke slurry, engine maximum power is reduced by about 6.2%, 19% and 21% respectively compared with burning diesel fuel, and the average exhaust gas temperature increases by about 5.3%, 19.1% and 34.2% respectively; the HC emissions reduced at 1200 r/min, and are similar to the diesel fuel at 1600, 1800r/min; the CO emissions are close to diesel fuel; the NOx emissions decreased; the exhaust smoke density is similar to diesel fuel at 1200 r/min , and is higher than diesel fuel at 1600, 1800 r/min.

Abstract:BaO(s1) was used as the first adsorption sites, and Pt (s2) was used as the second adsorption site, the micro-reaction kinetics simulation of NOx and PM in diesel engine by adsorber-reduction catalyst was calculated with the software of Chekmin. The results showed that in lean burn condition, gas phase NO(g), NO2(g) were stored in forms of NO2 (s1), NO2NO3 (s1), and NO3 (s1) on the surface of BaO, but in rich burn condition, N atoms in NOx desorption from surface of BaO combined with each other to form N2 molecular. Surface reaction was occurred between C (S) and reactive oxygen species O*. The absolute time, the ratio values of lean burn condition, exhaust temperature and oxygen concentration in diesel engine exhaust pipe have a great impact on removal of NOx and PM emission.

Abstract:The combustion characteristics were studied by using a 2.0 L GDI engine at medium and low speeds part-load. The effect of intake tumble and injection timing on combustion characteristics was analyzed. The results showed that increasing intake tumble could enhance airflow and combustion velocity at the operation condition of 1000 r/min, 0.1 MPa brake mean efficient pressure (BMEP). However, the advantage of intake tumble reduced when engine speed increased. At operation condition of 3000 r/min , 0.3 MPa BMEP, increasing intake tumble could cause combustion deterioration. The effect of injection timing has greater influence on mixture formation and combustion stability at operation condition of 3000 r/min than operation condition of 2000 r/min, and there is the best injection timing value between 300°CA BTDC and 320°CA BTDC at every operation condition. 

Abstract:The atomization characteristics of group-hole nozzle were numerically investigated with the revised spray model. The results show that due to the compromise effect of micro-orifice from the reduction of nozzle diameter and jet interaction from the overlapping part of spray, the spray of parallel group-hole nozzle is similar to that of the single nozzle, both of which have good axial symmetry. However, the spray penetration of the parallel group-hole nozzle is slightly lower than that of single nozzle with the equivalent hole area, and is significantly larger than that of single nozzle with the same hole diameter. With the increase of the hole spacing and inclined angle, the jet interaction decreases, which results in the reduction of the spray penetration and SMR of the group-hole nozzle. Meanwhile, the spray axial symmetry of group-hole nozzle is finally lost. Compared to the converging group-hole nozzle, it is faster for the diverging group-hole nozzle to lose the spray axial symmetry and decrease the spray penetration.

Abstract:The CLSVOF method which combined the VOF method and Level Set method was put forward to compute the flow of incompressible two-phase. The precision of the CLSVOF method for computing the convection transport and momentum transport equation was studied and the comparison was made between the VOF method and Level Set method by using some classical two-phase flows. The results show when computing the convection transport equation, the CLSVOF method has much better precision than the Level Set method; and when computing the momentum transport equation, the CLSVOF method can avoid the problem of spurious velocity current which can not be avoided by using the VOF method.

Abstract:The effect of the number of blades and load application on the reliability of turbine impeller was studied, and the reliability and failure rate models of turbine impeller of turbocharger under ultimate load were developed. The structural characteristics of turbine impeller were analyzed, and the probability distribution function of strength of turbine impeller capable of reflecting the effect of the number of blades was derived. For the failure mode caused by the ultimate load of over speed, the models of reliability, failure rate and mean life of turbine impeller were developed, which could embody the effect of the number of blades, load, strength and the operating cycles. Taking a turbocharger as an example, the behavior of the reliability and failure rate of turbine impeller changing as the number of operating cycles was studied. The results showed that as the number of operating cycle increased, the reliability of turbine impeller decreased, and the failure rate also decreased and approached to a stable value. Compared with the conventional methods, the models proposed can be applied to analyze and calculate the reliability of turbine impeller more scientifically.

Abstract:Vehicular powertrain testbench was designed by utilizing two load motors installed at both ends of the differential which simulated the driving resistance, and one drive motor which drove the powertrain system instead of I.C. engine. A LabVIEW based measurement and control system for the testbench were developed. CAN signals of powertrain’s master controllers, serial signals of electric driven system based on USS and MODBUS protocol were sampled and monitored at real-time and synchronously. The system integrated various communication protocols in one platform and had a good portability and scalability. This testbench was used in applications of reliability test for hybrid powertrain system with ISG (integrated starter/generator). The basic performances of key components of electromagnetic coupling power synthesis box, and the dynamic performance on simulated working condition were also tested so as to provide a valuable reference for control strategy formulation and parameter optimization. 

Abstract:To investigate the energy characteristics and pressure fluctuations of a twostage double-suction centrifugal pump, the standard k-ε and RNG k-ε turbulent flow models were chosen for the steady and unsteady flow simulations at 0.62, 0.8, 1.0，1.1 and 1.2 designed flow rate conditions. The results showed that the second multiple frequency of the impeller rotation dominated the pressure fluctuations in the suctions. The fluctuation amplitudes for all the monitored points in suctions were very similar and the difference was less than 1%. The second multiple frequency of the impeller rotation also dominated the pressure fluctuations on the impeller blade surfaces where the amplitude became larger than that at suctions. The blade passing frequency dominated the pressure fluctuations in the volute and the largest amplitude was at the point some distance away from the volute tongue. The amplitude of pressure fluctuation increased when the pump operation condition was deviated from the design point. In the volute tongue region, the pressure fluctuation amplitude of blade passing frequency at 1.2 designed flow rate is 1.25 times of the one at designed flow rate, while the ratio at 0.62 designed flow rate is 1.42. 

Abstract:In order to study the influence of tongue-impeller gap on the unsteady flow in a double-suction centrifugal pump, a research was presented on the internal unsteady flow, especially on the pressure pulsations. The large eddy simulation method with sliding mesh technology was used to investigate this kind of unsteady flow characteristics in a double-suction centrifugal pump at design condition. Five different impellers with different outlet diameters, corresponding to different tongue-impeller gaps were considered. The results indicated that the head rise showed an increasing tendency with lager tongue-impeller gap, while the efficiency had an overall downtrend. The results also showed that the blade passing frequency dominated the pressure fluctuations in the volute, while rotating frequency dominated in the impeller. Meanwhile, the tongue-impeller gap increasing resulted in a significant reduction of the maximum pressure fluctuation amplitude both in the volute and impeller. When the gap increased by 4%, the maximum amplitude at one time of blade passing frequency near the volute tongue was reduced by about 9%, while the maximum amplitude at two times of rotating frequency in the center of blade pressure side increased by about 38%.

Abstract:The flow fields in a rotating impeller, near the volute tongue of a centrifugal pump, were measured by the 2-D PIV technique. At the flow rate of Q/Qbep＝0.52, a counter clockwise recirculation flow existed on the blade pressure-side, when the blade was close to the volute tongue, a clockwise recirculation flow occurred on the blade suction-side. At the flow rate of Q/Qbep＝1.0, a jet/wake flow existed at the exit of the impeller. The results show that the effects of the volute tongue on the relative velocity distribution are more significant at the low flow rate condition than at the best efficiency point.

Abstract:Inner flow in a double-blade pump impeller, whose specific speed is 111, was measured under zero flow rate condition by using 3-D PIV test technology. In order to ensure the accuracy of 3-D PIV test, the external trigger synchronization system which was made with fiber optic and equivalent calibration method was applied. In Visual C++ 2005 platform, according to the velocity triangle, 3-D PIV velocity synthetic procedure was compiled to obtain the relative velocity synthesized by the absolute velocity and the circular velocity. The results showed that volute tongue had greater impact on the absolute velocity field within the impeller. There were vortices regions at three measurement surfaces within impeller, but the sizes and locations of vortices were different. Moreover, there was a low velocity region at the volute diffuser, the absolute velocity values in the region were less than 0.62m/s, and there were vortices at the volute diffuser. The axial velocities values of impeller passage, volute diffuser and region near volute tongue were different at three measurement planes. 

Abstract:Aimed at some complex CFD models which may generate very poor grid by using unstructured grid, and is bound to increase the difficulty of calculating, numerical simulation of a low specific-speed centrifugal pump was carried out between the unstructured grid and structured grid at the different operating points in CFX software. The results of simulation show that the pressure distributions of structured grid model is closer to the design value and separated vortex is more obvious near short blade surface region. Compared the simulation results with the experimental values, it is found that the result of structured grid can meet the design requirement. That confirms the numerical simulation computation is feasible with accuracy.

Abstract:On the basis of analyzing the relationship between pressure before the nozzle and nozzle area, radius of throw, a new type of variable-rate sprinkler was developed by using activity pieces and non-circle nozzle device on an impact sprinkler. The structure and working principles were presented. Experiment of hydraulic performances was conducted and analyzed. The water distribution isoline of single nozzle was plotted by using Matlab. Results showed that the variable-rate sprinkler with non-circle nozzle was able to operate reliably, and the triangle wetted area and square wetted area was obtained. Compared with the traditional variable-rate sprinkler, the variable-rate sprinkler with non-circle nozzle has better hydraulic performance and the spray uniformity is improved.

Abstract:The flow field of a centrifugal pump with the specific speed of 60 was computed by CFD method, and the analysis was made to the characteristics of energy conversion within impeller from aspects of working process and energy loss process. The impeller was divided into 8 regions by the radius. Under different operating conditions, characteristics in each region were demonstrated the power of pressure and viscous force, distribution of power density and turbulence dissipation rate, composition and distribution of the energy loss. The results indicated that efficiency was poor and it was influenced by the inlet blade angle in inlet region of the impeller, the middle region of impeller was important to the energy conversion, the outlet region of impeller had appreciable impact on the performance, and fiction loss was the main component of the energy loss.

Abstract:Based on the definition of the best submain position locations in which the same minimum pressure exists in uphill and downhill laterals, a method was developed for designing micro-irrigation paired laterals with emitters at homologous discharge rate, allowable maximum and minimum pressure along laterals were conditions needed to satisfy. When the designed emitter discharge, emitter space and one or two parameters (length, diameter or pressure head) of a paired lateral were provided, the unknown parameters and the best submain position could be designed at any field slope conditions. The results show that the final solutions can be obtained quickly and reasonably.

Abstract:Based on short term clogging test procedure in ISO clogging test methods for drip emitters, twelve kinds of dental labyrinth emitters were tested for anti-clogging ability under different operating pressures. The results showed that as the minimum size of labyrinth passage section increased, the anti-clogging ability of emitters was improved. When the minimum size of labyrinth passage section was greater than 0.6mm, the anti-clogging ability of emitters would be better. However, the design of labyrinth passage section showed more significant effect on the anti-clogging ability of emitters under 0.04MPa operating pressure. Aperture of the filter can select 1/5 of the effective aperture of minimum size of labyrinth passage section under 0.10MPa, and 1/7 of the minimum size of labyrinth passage section under 0.04MPa. In addition, the results also showed that intermittent irrigation could contribute to the improvement of anti-clogging performance of emitters under low operating pressure.

Abstract:Automatic supplying rape seed system for plot seeder was designed. It took electromagnetic force as power source and went with plot seeder. Key parts of structure and motion were analyzed. Automatic supplying seed system was able to accomplish supplying seed for 34 plots. By the supplying seed experiment without interruption at the different supply amount in the given time, the result showed that adjusting value and uniformity CV decreased with increasing of time. The uniformity CV was at the minimum range when the time was 8s and the minimum uniformity CV for rape seed was 7.59% at supply amount of 7 g. Loss rate for rape seed was 0.97% and error of supply seed was less than 3 mm. Compared with manual operation, the uniformity CV between the two metering devices was blow 1.5% for rape seed.

Abstract:The direct shear system dynamics simulation model was developed on the basis of the modified Mohr-Coulomb yield criterion by using ANSYS／LS-DYNA and a combination of Lagrange and smoothed particle hydrodynamics (SPH). The dynamics simulation experiments of direct shear on four kinds of soil have been carried out. The mathematic models of soil shear strength and shearing speed were established by regression analysis. The research on soil shear failure process and the influence law and mechanism of shearing speed on shear strength was done. The results showed that with shearing speed increasing, shear strength increased. Third-order relationship exits between shear strength and shearing speed with small shear modulus. Logarithm relationship exits between shear strength and shearing speed with large shear modulus. The effect of shear modulus on shear strength is large. The large shear strength is with large shear modulus.

Abstract:Based on the infiltration experiments in Yangling district, the objective was to analyze the scaling process of Philip model. The spatial variation discipline of scaling factors was found out and the pedo-transfer function was established for estimating scaling factors. The study showed that the scaling of infiltration process based on αA was the best among different scaling factors in Yangling district. Therefore, the infiltration curves in the regional scale can be scaled with αA. Meanwhile, the reasonable sampling number was calculated under the different confidence levers and required precision. The spatial variation discipline of αA by ArcGIS software was analyzed, and the pedo-transfer function was established to estimate αA. Accuracy of the estimate αA was analyzed in terms of pedo-transfer function, the results suggested that it has feasible and reliable for estimating αA, which could be used to achieve the conversion of soil infiltration between point and region. 

Abstract:A comprehensive evaluation model of soil nutrient based on BP neural network was set up, which contained 5 cryptic layer nodes and 3 layers. The rank classification criterion of soil nutrient’s assessment indicator system was chosen as the training sample and the test sample of the model. The training and the test were made by using Matlab software. The comprehensive evaluation of farmland soil nutrients was conducted in Ansai County. The results showed that simulation result of BP neural network was consistent with the expected result; the simulation result of BP neural network, fuzzy pattern and principal component analysis were exactly the same. 

Abstract:In order to ascertain the response of photosynthetic parameters of winter wheat during the course of soil water consuming from drought stress to re-watering to different dosage of water-retaining agent and make clear the acting mechanism of water-retaining agent, the pot experiment was employed and water-retaining agent was added to the soil at the following rates: 0 mg/kg, 27 mg/kg, 54 mg/kg, and 81 mg/kg. The results indicated that photosynthetic rate (Pn), transpiration rate (Tr), and stomatal conductance (Gs) of wheat were decreased, but water use efficiency (WUE) was increased after the application of water-retaining agent under drought stress. After re-watering, Pn, Tr, and Gs of CK were still higher, and those of water-retaining agent, from high to low, were as the following: 54 mg/kg, 81 mg/kg, 27 mg/kg. When soil moisture content fell to about 55% of field capacity, the photosynthetic parameters of each treatment were ranged in order from the higher to the lower ones as the following: 27 mg/kg, CK, 54 mg/kg, 81 mg/kg. WUE of different treatments were rank as the following: 84 mg/kg, 27 mg/kg, CK, 54 mg/kg. And with the increase of the amount of water-retaining agent, wheat biomass increased, but those of 81 mg/kg of water-retaining agent were significantly high compared with other treatments. Meanwhile, water-retaining agent had an effect on the relations among photosynthetic parameters of winter leaves. The correlations between Gs and Pn and Tr of wheat applied with 54 mg/kg of water-retaining agent were the most closely connected, next were the treatments with 81 mg/kg, CK and 27 mg/kg of water-retaining agent respectively. However, the connections of correlations between Gs and soil, WUE and those between Pn and soil water, Tr, and WUE all showed in the following order: 81 mg/kg, 54 mg/kg,CK, 27 mg/kg. It could be concluded that the treatments with 54 mg/kg and 81 mg/kg of water-retaining agent had significant effect on the correlations between photosynthetic parameters of wheat leaves. 

Abstract:The multi-hierarchy and multi-objective fuzzy theory was applied to establish a multi-hierarchy and multi-objective fuzzy evaluation model of regulated deficit irrigation comprehensive benefits. Using the information entropy theory, the impersonality weights of all hierarchy evaluation indexes were obtained, and the subjective weights given by experts to attain the comprehensive weights for the method of multi- hierarchy evaluation indexes were combined, the reliability of the model evaluation results was improved．At the same time, the model was used to evaluate and order the comprehensive benefits of regulate deficit irrigation integration benefits of mini-watermelon with different water deficit treatments in autumn of 2007. The results indicate that the water deficit can improve fruit quality, but the serious water deficit and moderate water deficit would decrease yield in fruit spreading growth stage. The water deficit has little influence on yield and quality of fruit in fruit maturing stage. During the seeding stage, blossoming and bearing fruits stage, fruit spreading growth stage and fruit maturing stage, the irrigation standard of 0.75 Ep , 0.75 Ep , 1.25 Ep and 1.00 Ep was adopted respectively, and could get the perfect comprehensive benefits of regulate deficit irrigation integration benefits.

Abstract:The cold state PIV analog equipment was designed to explore the movement law of the biomass chars and ceramic balls mix flows in the down flow reactor. By simulating the cold state, the stability and continuity of the equipment of ceramic ball and biomass char, the equipment implements even, precise and continuous down the mix of two particles were tested; it satisfied the requirements of the two particles different mass proportions in the experiment; by testing, the equipment can satisfy the experiment; many bright and white stripes formed by the light’s reflection and refraction in two sides of the round tube axes in PIV were avoided by using the biomass char, and the veracity of data were greatly enhanced.

Abstract:Active air distribution way was taken to the experimentally study on the tar cracking property in downdraft fixed-bed biomass gasifier. The results showed that the reaction was uniform in the same section and the gasifier had a thicker layer at high temperature under the active air distribution, which provided good conditions for tar cracking. The optimum air distribution way was achieved by the experiments, and the tar content in gas was about 600 mg/m3 in the range using corn stalk as the material with high heat value about 5400 kJ/m3. The effect of ash layer thickness and the other factors on tar cracking and gas quality was also studied. 

Abstract:The primary factor of influencing the process of biomass hydraulic briquetting was analyzed and studied. The experimental result indicated that the best range of containing water ratio was 0.15～0.18. Based on the results, the simulation of the process of biomass hydraulic briquetting was carried out with the finite software ANSYS at first. Then the displacement and strain in the biomass extrusion process was analyzed, and the rule along with the disciplinarian of frictionchanging in the process was obtained. All these provided credible conditions for the study of biomass briquetting mechanism. 

Abstract:The mathematic model of biogas heat pump with generator was established. It included biogas engine model, compressor model, heat exchanger model, generator model and etc. Energy supply performance for biogas heat pump with a generator was studied by using the models. The results show that the system has good power generation performance, heat supply performance and refrigeration performance. When the system runs at low speed, the efficiency of energy utilization is more, and the max COP of the system is about 5. The results prove that the system is with a high actively and fully utilizing energy technology. It has good partial load characteristic and good effects for energy saving and environment protection. The voltage of the generator is 28.8V, which is enough for the system operating.

Abstract:The sewage sludge of Shenzhen Binhe Wastewater Treatment Plant was used as the research object, the dry sludge and returned sludge as the water amendment, the leaves powder and woodchip as C/N and water conditioner, the four aerated static pile (ASP) systems (1.5 m×1 m×1.5 m) as the composting equipment, the sewage sludge composting process conditions were studied. The results showed that using the dry or returned sludge as water amendment to mix with the fresh sludge to the volume ratio of 1∶1, the water content of the mixture could meet the composting conditions. Using leaves powder or woodchip as the C/N and water conditioner to mix with fresh sludge is more useful than using the dry or returned sludge, but it could increase the cost of the compost. For the different treatments the time the temperature of the compost over the 55℃ is more than 12 d, and the compost satisfied the standard of harmless and stabilization. The two pilot-scale ASP systems (10 m×2 m×1.5 m) were used to confirm the conditions come from the small ASP systems experiment. The results indicated that one volume of fresh sludge mixed with one volume of dry or returned sludge the water content of the mix is appropriate for composting, but the volume ratio of 1∶1 fresh sludge mixed with dry sludge is more effective than that of returned sludge and the compost could meet the standard of harmless and stabilization. 

Abstract:The possibility of using near-infrared microscopic imaging to discriminate meat and bone meal (MBM) in concentrate supplement was investigated. Samples of MBM and dairy concentrate supplement were collected, and the sediment particles were prepared and arranged on polytetrafluoroethene (PTFE) background plate for near infrared imaging. Image size was 5000 μm×5000 μm, using 50 μm pixel resolution (10000 spectra were obtained). Each spectrum was across the wavelength range 7800~4000 cm-1 , with 8 cm-1 data resolution. Both principal component analysis and fuzzy clustering analysis were used to extract and present relevant information from NIR microscopic imaging data sets. The results showed that MBM could be distinguished from dairy concentrate supplement by the scores from principal component analysis, and the samples were subdivided by using fuzzy C-means clustering based on the PCA analysis. It is demonstrated that NIR microscopic imaging approach is one of the most promising methods for detecting MBM. 

Abstract:The efficient automatic coating preservation equipment called clean egg coating machine was independently developed, with which clean eggs can be coated and dried. Meanwhile, the control system for batch production was also developed. Experiments of egg in-chain line speed under 6 kinds of different motor frequencies at 5, 10, 15, 20, 25 and 30 Hz respectively were done to test the actual production capacity of the equipment. As a result, the best speed value were found at 12.01 mm/s with the corresponding capacity value at 4804 pieces/h under the following conditions: temperature is 25℃, RH is 60%, spray pressure is 0.6 MPa, spray quantity is 43.6 mL/min, and drying capability of fluid is 1.71 kJ/s. The dryer length is 50cm and the drying time of clean eggs is 4.16 s. 

Abstract:A multi-functional ultrasonic-ozone washer was designed by integrating the technologies of ultrasonic washing and ozone washing with the functions of decontaminating, sterilizing and reducing pesticide residues. The washing process of the washer was auto-controlled by microcomputer program, including the steps of spray rinsing, ultrasonic-ozone washing, and re-spraying. The two sprayers were disposed on the tank wall vis-a-vis in stagger position. Combined with the control program, the sprayers enabled the fruits or vegetables in the tank to move and roll intermittently during washing, which ensured all the surface of the wash matter can be cleaned, and the ozone-water blend effect was improved. Experiments on strawberry washing showed that the washer had no significant influence on the strawberry quality, and the sterilization rate of microorganism on strawberry was more than 90%, the degradation rates of equigard, acephate, dimethoate all reached about 85%. The washer had significant effect of decontaminating, sterilizing and reducing pesticide residues.

Abstract:The aromatic compounds in blackberry juice before and after ultrahigh pressure (UHP) treatment were evaluated by sensory evaluation and analyzed by combining SPME with GC-MS method. The results showed that after UHP, the categories of aromatic compounds in blackberry juice were the same as those in original samples, however, the content had a little change after UHP treatment. The alcohols and esters contents were decreased by 4.8% and 11.1% respectively after 300 MPa, 10 min treatment. While the contents of aldehydes and the ketones were respectively increased by 12.06% and 14.59%; and the alcohols, esters and aldehydes contents were increased by 4.9%, 26.86% and 9.9% after 400 MPa,10 min treatment. But the concentrations of them were not changed significantly after 200 MPa, 500 MPa and 600 MPa, 10 min treatment. The sensory evaluation results demonstrate that blackberry juice under 400 MPa, 10 min treatment has its typical flavor, and matches well with the GC-MS analysis results.

Abstract:In order to investigate the effect of 1-methylcyclopropene combined with controlled freezing-point storage on grape texture, the change of ‘ZANA’ grape flesh texture parameters was studied by using texture profile analysis with a texture analyzer. The result showed that softening of grape fruit was delayed by 1.0 μL/L 1-methylcyclopropene combined with controlled freezing-point storage. The hardness, springiness, cohesiveness, chewiness and marketable fruit rate of grape fruit treated by 1-methylcyclopropene are higher than cold storage and controlled freezing-point storage. The hardness of grape has a good positive correlation with resilience. The springiness of grape has good positive correlations with resilience, chewiness and springiness. The marketable fruit rate of grape has a good linear relationship with fruit hardness. In conclusion, TPA test can reflect the change of grape fruit texture during storage and fit for evaluation of the quality of stored grape.

Abstract:Aimed at determining the maturity degree of citrus fruit non-destructively, three tone images were generated by dividing hue range 30°~120° of fruit image equally to three parts. Scale invariance and spectra of multi-fractal were analyzed. Height and width of multi-fractal spectra were extracted as features of color and luster of pericarp of fruits, and were set as input of BP neural network. With total soluble solid contents as the output of network, the neural network maturity degree model mapped fruit image into degree of maturity. The correctness of inspection test was 82%, which showed that maturity degree of citrus fruit could be detected non-destructively based on multi-fractal spectra. 

Abstract:An automatic navigation system was developed on XDNZ630 rice transplanter using RTK-GPS technology. The steering mechanism, gear change mechanism and transplanting mechanism of the rice transplanter were modified from manual control system to electronic control system by using servo motors. According to the position information of the rice transplanter acquired from GPS receiver and vehicle sensors, the close-loop feedback control system of steering was built. The system can accurately control rice transplanter to follow row navigating and turn around at the end of the field by PID tracking method. The road and field experimental results indicated that the lateral tracking error could be kept within 10 cm when the speed of the rice transplant was not greater than 0.6 m/s. The control system can completely satisfy the precision requirement of rice transplanting. 

Abstract:In view of the existing problems of current picking manipulator, an articulated picking manipulator with four degree of freedom was developed. In order to harvest fruits and vegetables of the target space flexibly and efficiently, meanwhile to reduce operating space and structure size of the manipulator as much as possible, the general structure optimization method of the articulated manipulator for picking fruits and vegetables was proposed, which was applied in random cube of the picking space. The mathematical models were constructed by taking the workspace for constraints, and the Matlab optimization Toolbox was applied to realize the proposed method. For verifying the availability of the method, the structure parameters of the designed articulated picking manipulator were optimized by referring to the example of the cucumber picking operation in greenhouse; and the motion planning experiments of the optimized manipulator were carried out. Experimental results showed that the optimized manipulator could cover the whole required target space of the cucumber harvesting operation, and also could reach the limit points and other picking points of the target space, the maximum positioning errors of the x,y,z axis were respectively 4.3 mm,5.6 mm,6.8 mm, so it could basically satisfy the requirement of the cucumber picking operation. 

Abstract:In order to solve the problems of weeding robot including the flexible movement in field and removing weeds without injuring crop seedlings, the principle of intelligent weeding robot system and the mobile robot platform were studied. The mobile platform was a four-wheel driven and four-wheel steering robot. It could move within the speed of 0~1.5 m/s and each leg could rotate freely around Z-axis of itself. A three-finger manipulator was also designed. All the three fingers could rotate around their public-axis and one of them could also around its own Z-axis. When the robot worked, based on the location information of seedlings and weeds gotten by the machine vision, the rotation speed of movable finger could be controlled to avoid injuring the seedlings while the two fixed fingers would remove the weeds between two crop seedlings continuously. The simulation of the trajectories of three-finger manipulator showed that more than 90% weeds could be removed when a manipulator was installed on each side of crop rows.

Abstract:By analyzing the shortage of traditional approach,a new individual trees recognition method was proposed. Firstly, the generalized Gaussian function was used to analyze the fitting pulse shape LiDAR data, and the high density point cloud and the waveform parameters were obtained, then the non-ground points were gained by establishing DEM; secondly, the spatial characteristics of point cloud was computed to receive forest points; lastly, Markov random fields were exploited to label individual trees in 3D. The experimental results show that this method can effectively improve the recognition accuracy, especially in the low dense, small trees identification effect, and the average recognition accuracy is 75%. 

Abstract:The key technology for map-based variable rate application of fertilizer lies in fertilizer should be applied precisely at each location within the field according to prescription map. Software for variable rate application control was developed based on object-oriented programming approach. A kind of algorithm for real-time application map identifying relying on machine location was designed and successfully implemented. Field test showed that prescription map cell was identified less than 100 ms, which could meet the requirements of actual field application. A model to determine positional lag was developed for map-based variable rate application system by analysis of factors causing position lag. In addition, field tests were conducted and result showed that delay time was about 1.84 s.

Abstract:Different from traditional methods, a novel poor information measurement error prediction method based on grey system theory and bootstrap theory was presented. At first, all calibrated measurement error sources were calibrated, and all measurement error transfer coefficients were calculated, and the calibration data of all error sources were sampled based on bootstrap theory, and predictions of calibration data of all error sources were gained by a grey bootstrap fusion model. Then the error prediction values for dynamic measurement of poor information were got in terms of error combination principle. At last, in an example of a general dynamic measurement, the predicting measurement errors were acquired by this novel proposed method and the actual measurement errors were shown to be in a good agreement with each other, and the validity of the proposed method was also represented.

Abstract:Artificial neural network (ANN) and fuzzy math were introduced to the design filed of CNC software for realizing the fault tolerance of CNC interpolation and improving the reliability of software. In addition, function aspects (velocity, acceleration, chord error, prediction accuracy, fault tolerance, real time ) from the experiment on non-uniform rational B-spline (NURBS) interpolator based on ANN were evaluated in detail. The experimental results show that the NURBS interpolation based on ANN can not only meet the requirements of the function aspects, but also realize the fault tolerance of CNC interpolation, which may provide a new strategy in the improvement of the reliability of CNC software. 

Abstract:The surface morphology of the membranous wing of the oriental mole cricket (Gryllotalpa orientalis Burmeister) was examined by scanning electron microscopy (SEM). The contact angles of water on the membranous wing surface of the oriental mole cricket were determined with an interface tension/wetting-angle measuring instrument (model OCA20). The relationship between wettability of the membranous wing surface of the oriental mole cricket with geometrical structure of its membranous wing surface was analyzed. The results showed the difference of each part of the membranous wing surface in the geometrical structure. The average apparent contact angles of water on the membranous wing surface of the oriental mole cricket was from 94.4° to 118.6°, indicating a hydrophobic ability. The comprehensive action of the geometrically structural surface and the hydrophobic function was the dominant mechanism of preventing adhesion of soil and water from their membranous wing surface. This research established the theoretical foundation on exploring all kinds of membranous wings and improving the waterproofness of green thin film.

Abstract:The relationship between system alignment errors and four equivalent misalignments was built through 3-D tolerances modeling theory and transfer matrix accumulating method based on feature variances. Tooth contact analysis algorithm with consideration of alignment errors was provided, and the contact pattern digital features were completely defined. In the situation of transmission performance requirements and cost constraints, the accuracy of parts was optimized based on genetic algorithms by using meshing relative to alignment errors sensitivity as the optimal objective function. Taking a pair of spiral bevel gears as an example, the feasibility of tolerance optimization method was verified by comparing the meshing and transmission errors before and after optimization.

Abstract:A model of laser milling on Al2O3 eramic was established based on ANSYS finite element software. Laser milling process was analyzed by APDL code, and the dynamic distribution of the temperature field during the milling process was studied. The influence of the laser power and scanning velocity on the milling width and depth were investigated. According to the numerical simulation, the relevant parameters were used in the laser milling experiment. It indicated that the numerical simulation results were consistent with the experiment, the effect of laser milling on Al2O3 ceramic could be accurately predicted by the established model. The width and depth of laser milling were increased by laser power and decreased by the scanning velocity. Compared with the scanning velocity, laser power had more important influence on laser milling.