Abstract:A 3-D simulation model including the inlet and the cylinder was built to study the backfire mechanism of PFI hydrogen internal combustion engines. A method controlling the backfire was put forward through optimizing the hydrogen injection angle. The low concentrated mixture gas was flow into the cylinder first after the intake valve opening, which can then lower the temperature of the exhaust gas and hot point inside the chamber. Based on the simulation model, the hydrogen injection angle influenced on the concentration and temperature of the mixture gas with the engine at different working speeds and conditions was investigated. The optimized hydrogen injection angle causing no backfire in all working conditions were found. It was proved by the experiment that the hydrogen internal combustion engine with the optimized hydrogen injection angle worked normally without backfire when the equivalent fuel air ratio of mixture gas reaching or even exceeding the stoichiometric fuel-air ratio within the speed range.

Abstract:The two-fluid method using linear cavitation model was utilized to simulate GDI multi-hole injector nozzle flow. The evolutionary law of the cavitation flow pattern was analyzed. Cavitation criterions were summarized and compared. Results showed that cavitation was formed at the hole corner and the gap between the moving needle and valve seat. Cavitation flow pattern was unstable and changed with time. Nozzle flow rate decreased and while exit velocity increased due to the cavitation. Also each hole flow rate was different. The critical cavitation number was efficient to predict the cavitation. The non-cavitation flow of GDI multi-hole injector could only be appeared when the injector worked in low injection pressure and high ambient pressure for stratified combustion applications.

Abstract:In order to establish spray break-up model of multi-hole injection on gasoline direct injection engine, Huh Gosman model was analyzed and evaluated. The primary break-up particle size distribution formula was built based on injection pressure. The spray break-up model was built for gasoline direct injection in cylinder. Finally, by establishing the capacity spray experiments, gasoline free spray experiments were carried out to verify the rationality of the model. It is found that estimating initial droplet size by experience formula to evaluate second break-up model, the spray penetration calculated with Huh Gosman model is smaller than experimental results. Through establishing primary break-up particle size distribution formula and modifying Huh Gosman model, the simulation results and the practical results are close to each other. At last, free spray under different injection pressure were simulated with above established models. Results matches well with the experimental results and the maximum average error is less than 5%.

Abstract:A Weichai-WP12 heavy-duty diesel was taken as the research object and the influence on two-stage turbocharged system was researched, according to contrasting the two states of the IVCA which control mode was open or close. It was also analyzed that the effect on combustion process by key gas path parameters of diesel engines under each speed and middle load condition. The results show that the NOx and soot compromise exhaust emission was significantly declined by IVCA when the injection timing was delayed further after top dead center. At the same time, it was found that IVCA could decrease air intake flow and backpressure, and then it was considered as a useful way to improve the effective thermal efficiency when engines ran under high backpressure condition. The optimization matching process between boost system and IVCA under middle load working condition could come true if the influences of IVCA on operating principle of boost system were found , while the key air path parameters and fuel parameters was collaborated and controlled precisely.

Abstract:Diesel oxidation catalyst was installed in front of diesel particulate filter. The engine exhaust temperature was improved by insufflating diesel oil into vent-pipe upriver diesel oxidation catalyst. The engine exhaust flow was reduced to further improve the exhaust gas temperature and achieve the regeneration of diesel particulate filter. The system was consisted of fuel injector, diesel oxidation catalyst and diesel particulate filters. Study on regeneration characteristics of this system on engine test-bed, including the temperature characteristics of the diesel oxidation catalyst in regeneration, the relationship of injection flow rate and temperature, DPF regeneration process and the fuel economy and secondary pollution of regeneration. The results demonstrates that DOC assisted DPF regeneration can be successfully achieved under idle condition, diesel oil consumption under regeneration process is 120.5g, emissions of CO and HC under regeneration process are 12.4g and 1.1g, respectively.

Abstract:The particulate status characteristics of diesel engine particulate were studied by using thermo gravimetric analysis, scanning/transmission electron microscopy (SEM/TEM) and staged sampling particulate system methods. The variation of the composition, size distribution and microstructure of particulate with different ethanol ratios were studied. Results showed that soot accounted for about 75% of the total particulate mass. With the increase of ethanol ratios, the proportion of soluble organic fraction (SOF) increased and sulfate decreased. With the increase of ethanol ratios, the particulate of size range 0.78～1.4μm decreased and the proportion of 0.25μm increased. The distribution of particulate moved to small size. The particulate size decreased and agglomeration improved with the increase in the proportion of ethanol ratios. The microstructure of the particulate was polymerization, core-shell and disordered.

Abstract:Multidisciplinary coupling rapid design and optimization of mechanical structure was researched, and multidisciplinary design optimization of diesel engine motion mechanism was proposed. The comprehensive performance of lightweight, thermal, vibration and kinematic were considered in optimizing the diesel engine motion mechanism. Aimed of lightweight, 3-D parametric model of crankshaft-connecting rod-piston were founded, and the performances of lightweight, vibration, thermal and kinematic was set as constraint. Based the theory of collaborative optimization, multidisciplinary design optimization of the diesel engine motion mechanism performed good results.

Abstract:Usually the evaluation index of optimal pump operation solution is single. An optimal pump operation model which contained the constraint of start-stop pump unit was developed, and projection pursuit evaluation method for scheme optimization was proposed. The ant colony optimization algorithm was used to calculate the model. The heuristic information and the pheromone trail update method were improved by analyzing characters of the model for better performances. A calculation example for the No.4 Jiangdu pumping station was conducted. The results from ant colony optimization algorithm showed that 29.2% of energy fee could be saved under the designed operation condition, which was compared with the result from dynamic programming with successive approximation algorithm under the same discrete condition, and was better with 2.8% of the result from dynamic programming. The results from ant colony optimization algorithm had less times of the blade adjusting, and shorter operating time of the pumps. Projection pursuit evaluation could give consideration to multiple evaluation indexes. The evaluation result of projection pursuit not only has low electric fee, but also suitable for practical operation, which indicates that ant colony optimization algorithm combined with projection pursuit evaluation method can provide a high application value to the field of optimal operation of pumping stations and related fields.

Abstract:The shut-down process of bulb tubular pumping station with VFD will be a stabile and safe transient process through the speed lowing gradually. The features of normal shut-down process with VFD were analyzed. The flowing rate balance and torque dynamic balance equations were established. According to the characteristics of the VFD, the speed lowing law was designed and the main hydraulic parameters were simulated during the shut-down transient period by the numerical calculation, the optimal combination between the speed-lowing, the starting time point and closing time of the gate was discovered. The findings of the study provided various shut-down suggestions for safety and stability operation of bulb tubular pumping stations with VFD.

Abstract:The energy model of an intake pump station was firstly introduced. Then, an open loop optimal control approach and a model predictive control (MPC) approach were introduced to improve the operational efficiency of intake pump stations. They lump time of use (TOU) tariff and intake level into their objective functions, and take total water consumption and the low and high limit of the clean water reservoir as constraints as well. An intake pump station, equipped with three constant speed pumps, was taken as a case study. The conventional optimal control and the MPC approach were investigated, respectively. The advantage of the MPC approach was convinced by the simulation results. Further, the load shifting of intake pump stations was also achieved through the proposed control approaches.

Abstract:The design of inlet sump is an important part in whole project-design. With the aim to investigate the change of inlet chamber affected from impeller under different flows, an inlet sump model with and without impeller was analyzed with numerical simulation method. The results revealed that the fluid field of inlet sump without impeller almost had no change in different flows. The situation in the one with impeller was complicated. The inlet recirculation effect of impeller in part-load had a main influence on the outlet of inlet sump which grew with decreased flow. The distribution uniformity and velocity-weighted suction angle changed down with decreased flow rate. Tangent velocity appeared obviously in the outer of sump outlet at the flow rate of 0.4Q0. It had similar distribution with tangent velocity curve in the vortex and upstream developed in sump. All of these can provide an important reference for design and optimization of large vertical pump unit.

Abstract:In order to investigate the constant pressure control characteristics of centrifugal pump, a testing system on constant pressure closed-loop control of centrifugal pump water-supply system，which was based on internal PID controller of frequency converter was set up by using the virtual instrument. An innovative form of the outlet of the pump system composed of three ball valves was remodeled. It could change working condition quantitatively and rapidly. The outlet could create similar step disturbance. A LabVIEW test program was compiled to do research on control characteristics of constant pressure centrifugal pump system. The set range of the given pressure of the constant pressure control system was concluded. Contrasting the control characteristics of the fixed parameter PID regulator under different working conditions, it is showed that the control characteristics of the fixed parameter PID regulator are not good under the working conditions that changes quickly and extensively. Analyzing the control characteristics of the fixed parameter PID regulator and the variable parameter PID regulator under the same working condition, it is discovered that the variable parameter PID regulator is more applicable for the constant pressure control system.

Abstract:The unsteady flow in a mixed-flow pump was simulated based on RANS solver embedded with SST turbulence model and SIMPLEC algorithm. The time-domain and frequency-domain of pressure fluctuations at four representative monitoring surfaces under different flow rate and rotational speed conditions were analyzed. Comparison between averaged calculated power and test data verified that interior flow simulated by this numerical model was relatively accurate. The numerical results showed that the maximum pressure fluctuation appeared at impeller inlet where the pressure fluctuation amplitude increased from hub to shroud. The dominant frequency at impeller inlet and impeller outlet was the impeller blade passing frequency, but the dominant frequency at middle and outlet of the stator was correlative with the flow rate. The pressure fluctuation became stronger as deviating from the optimum flow rate, especially at impeller inlet when small flow rate conditions. The optimum flow rate conditions of different rotational speed had a similar dominant frequency of pressure fluctuation, the pressure fluctuation amplitude increased with the rotational speed increasing.

Abstract:With the aim to investigate the difference of different specific speed pumps used as turbines,numerical simulation of different specific speed pump was performed. The efficiency between its two modes and the variations of flow rate and pressure head conversion factors of pump as turbine (PAT) with different specific speed pumps were analyzed. Meanwhile, the power loss distribution within different specific speed PATs were presented. Results showed that the flow rate and pressure head were increased when a pump was operated as a turbine. The efficiency of PAT was no more than its pump mode. The flow rate and head conversion factors decreased with the increase of specific speed. Power loss distribution within each hydraulic part showed that it was the power loss within impeller that took up the majority of the total power loss and this tendency grew with the growth of specific speed. Therefore, the optimization design of PAT should focus on impeller research.

Abstract:Near infrared spectroscopy (NIRS) is a powerful tool in the analysis of the soil compositions as well as soil physical and chemical properties. Artificial neural networks (ANN), genetic algorithm (GA), wavelet transform, support vector machine (SVM) and other modern data processing algorithms have made estimation and analysis of the soil parameters more accurate and stable since they can eliminate spectral error caused by outside interference and efficiently extract spectral information. It is still necessary to eliminate the impact of soil moisture and particle size on soil spectra in the in-site measurement. Development of the portable and vehicle-mounted real-time soil spectral analyzer is an important measure to promote the practice of precision agriculture. The developed vehicle-mounted soil on-line spectrophotometers have realized the analysis of several soil parameters, and reached a very high accuracy. It is a trend to develop multifunctional vehicle-mounted real-time soil spectral analyzer in the future by which the correction of the spectra can be performed with the data fusing of the spectral data and other dielectric or mechanical properties. The modern spectroscopies, photoacoustic spectroscopy (PAS), laser induced breakdown spectroscopy (LIBA), and terahertz (THz), have shown the great potential in the analysis of soil compositions and parameters. It is needed to carry out basic researches to reveal the spectroscopy characteristics of soil samples in different types and conditions.

Abstract:Visible/near-infrared spectroscopy (Vis/NIRS) was investigated for determination of soil properties, namely, available nitrogen (N) and available potassium (K). In order to improve the predictive precision and eliminate the influence of uninformative variables for model robustness, Monte Carlo uninformative variables elimination (MC—UVE) methods were proposed for variable selection in available N and available K NIR spectral modeling. Partial least squares (PLS) models analysis was implemented for calibration models. The modeling variable number was reduced to 210 from 751 for available N calibration model and 150 for available K calibration model. The performance of the model was evaluated by the correlation coefficient (R), RMSEP. The optimal MC—UVE PLS models were achieved, and R, RMSEP were 0.84, 17.1mg/kg for N and 0.76, 15.4mg/kg for K, respectively.

Abstract:In order to reveal the aftereffects of different nitrogen and water regulation levels on rice, pot experiments were carried out to study the aftereffects of short-term and long-term physiological indexes in different water-nitrogen interaction models at jointing stage. The results showed that optimal combination of water and nitrogen had compensation effect on physiological activity in a short-term after rewatering, while long-term aftereffect of delaying senescence was found at late growth stage. The single factor of water and nitrogen had significant influence on chlorophylls, fluorescence parameters, MDA, etc. in the short term after rewatering, and the collaborative interaction of water and nitrogen had reached to significant level in 15d after rewatering. The interaction effect of water and nitrogen is different for different water stress level. The yields of heavy drought treatments increased with the improvement of nitrogen supply, but were lower than other treatments. Accordingly, the heavy-drought should be avoided in rice jointing stage, and soil moisture content can’t hold less than 70% soil water rate. The yields of sufficient irrigation and slight-drought treatments reduced with the increasing of nitrogen supply. Therefore, high level of water and fertilizer at jointing stage did not assure high yield. The treatment of rewatering combined with lower nitrogen supply after slight-drought can obtain the best effect on water saving and yield guarantee.

Abstract:With the aim to understand the spatial distribution of soil moisture along slopes, the method of multi-electrode electrical resistivity tomography was used on two 400m length grass slopes of Diedie and Yunwu Mountains as study area. Both the two longitudinal transect lines were set up to detect the soil resistivity and water moisture by more points simultaneously and continuously. Results showed that there was a good statistical correlation between soil resistivity and moisture content on Yunwu Mountain (R2=0.78), and this suggested that it was feasible to determine the spatial variation of soil moisture through measuring spatial distribution of soil resistivity on slope. On Yunwu Mountain, the soil electrical resistivity gradually increased from the top slope to the mid slope, and then decreased to the bottom. While, on Diedie Mountain, it decreased from the top slope to bottom gradually; the light, mild and severe dry layers occurred in 1～3m, 3～4m and 6～17m soil layers on Yunwu Mountain respectively; While, on Diedie Mountain, the light and severe dry layers occurred in 3m, 6m and below 6m soil layers respectively.

Abstract:A series of field irrigation experiments of bare plot (BP), plastic film mulched plot(PFP) and corn straw mulched plot(CSP) were conducted during the seasonal freeze-thaw period. The effects of irrigation at different stages on soil temperature and soil freeze-thaw characteristics were analyzed. The results showed that the soil temperatures of plots irrigated earlier in freezing period were lower during the freeze-thaw period. The irrigation had a little effect on the soil temperature of BP and PFP in the thawing period, and the irrigation accelerated the thawing of the surface frozen layer. The soil temperatures of CSP irrigated at thawing period were lower and had a smaller variation. The mulching of corn straw went against soil thawing. The irrigation had a great effect on maximum soil freezing depth in the rapid increasing stage of accumulated negative soil temperature at the depth of 5cm.

Abstract:Dry anaerobic digestion of dairy manure under thermophilic temperature (55℃) for biogas producing was investigated, including the effect of different inoculation ratios on biogas producing, and the changes of biogas and methane producing, pH value, concentrations of ammonia, volatile fatty acid and total alkalinity during digestion. Inoculated dairy manure (the ratio of inoculums and dairy manure was 3∶10) was anaerobic digested 15 days under continuous mechanized mixing (8r/min), and total solid biogas production, average daily biogas production, the maximum daily production and the average content of methane reached to 311mL/g, 2.73L/(L·d), 5.23L/(L·d) (3rd day) and 57.1%, respectively.

Abstract:Evaluation of anaerobic co-fermentation of cattle manure (CM) and food waste (FW) was conducted in bath test at 35℃. Effects of mixing ratio on hydrogen yield, pH value, composition of dissolved fermentation products, and VS degradation rate were investigated. Results showed that a mixing ratio of 40∶40 would significantly enhance the efficiency of hydrogen production, and the maximums of hydrogen yield and VS degradation rate (17mL/g and 27.9%, respectively) were obtained. It is found that mixing ratios lead to different fermentation type. Mixing ratio of 40∶40 achieved pH value of 5.5 and butyric acid type fermentation. At multi-FW case, phenomenon of no hydrogen production, ethanol as dominant dissolved fermentation products and pH value below 4.0 was observed. As far as case of multi-CM, low hydrogen production rate was achieved as well as acetic acid as dominant dissolved fermentation products and pH value above 6.0.

Abstract:Selective adsorption of CO2 from its mixture with CH4 on several commercial molecular sieves was studied at ambient temperature(25℃) and low pressure (0.2MPa). The behaviours of the molecular sieves were compared by using three basic parameters: selectivity, adsorption capacity and regenerability. The results indicate 3A and 4A molecular sieves have low CO2 adsorption capacity. However 5A and 13X molecular sieves show high efficiency in dynamic separation of CH4 and CO2 when the adsorbents are used for the first time. The separation coefficient between CH4 and CO2 on 13X molecular sieve is higher than 5A, which proves 13X molecular sieve show better performance in separating CO2 from its mixture with CH4. But 5A and 13X molecular sieve could not be regenerated completely by vacuuming and the adsorption/regeneration performance became stable from their second use. The reason why separation performance of 5A and 13X molecular sieves decrease is explained by FTIR spectroscopy that the partial poisoning of the molecular sieves happened. That is to say the regenerability of the two molecular sieves need improve.

Abstract:With the aim to explore the efficient application of microwave liquefied product, experiment on the synthesis of polyurethane (PU) with microwave liquefied product from corn stover instead of petrochemical polyol was carried out. The optimized synthetic process of PU was 0.30g foam blowing agent and isocyanate index 1.0. The biodegradable property of the composites was investigated by means of bury test which showed 18.71% degradation rate in six months. The thermal gravimetric analysis indicated four phases in the thermal pyrolysis of PU. All the results indicated microwave liquefied product from corn stover could be used for the production of PU foam while the material property was to be characterized and improved.

Abstract:With Aspen Plus software, the simulation of the whole process of bio-syngas production from gasification via pressurized interconnected fluidized beds was carried out, and the model was validated by the comparison of simulation results and experimental results. The effects of gasification temperature (Tg), gasification pressure (pg) and steam to biomass ratio (S/B) on bio-syngas composition, H2/CO ratio, gasification proportion, bio-syngas yield, and carbon conversion were studied. The results showed that gasification temperature, gasification pressure and S/B had great influences on the biomass gasification process and the suitable gasification temperature and pressure was around 800℃ and 0.4MPa.

Abstract:The water-insoluble lignin (WIL), water-soluble lignin (WSL) and kraft black liquor (KBL) were performed on a thermogravimetry coupled with Fourier transform infrared spectrometry (TG—FTIR) to study the impact of sodium cation on lignin CO2 gasification, respectively. The TG profiles of the WSL and KBL were analogical during the whole reaction owing to the presence of sodium cation. The WIL and WSL had similar chemical structure, but there were different reactivity of CO2 gasification. Sodium cation on lignin structure had a control effect on the formation of CO in the CO2 gasification of WSL.

Abstract:With the aim to ensure the integrity and objectivity of agricultural products traceability chain and provide agricultural information to consumers, a GPS-based origin positioning and identification system was designed for agricultural products, especially for the regional agricultural products and products labelled with protected destination of origin. The GPS model was integrated with electronic scales with the information of agricultural products. The practical application shows that the system can effectively verify the labeled information with GPS information to realize the origin positioning and identification for agricultural products.

Abstract:Fuzzy information of corn juices was automatically evaluated based on a sensor array. The concept of weights was introduced for different taste sensory evaluation aspects of corn juices. The conversion of the qualitative and quantitative information was achieved. At the same time, adjustment of a comprehensive cloud model was completed based on the difference of weight. According to the requirements of the different evaluation aspects of corn juices including sweetness, soursweet and flavor, sensor array were analyzed and combination of different sensor array signals were obtained. Fuzzy neural networks were built for prediction of corn juices taste fuzzy information. The information for different aspects collected from sensor array was input. The information from cloud model according to sensory evaluation was output. With training fuzzy neural network, fuzzy layer center value, the fuzzification layer node width values and fuzzy decision-making regulation parameters were obtained to determine the network structure. The forecast analysis showed that the system allowed good effect with 0.00243~0.09177 error rate in the process of automation evaluation of fuzzy information for corn juices.

Abstract:Based on least squares—support vector machine (LS—SVM), the effective wavelength (EW) in visible/near infrared (Vis/NIR) region was proposed as a new approach for the variety discrimination of pears. 210 pear samples were used for the calibration set, while 30 samples for the validation set. After partial least squares (PLS) analysis, the EWs were selected according to the X-loading weights and regression coefficients, and an EW—LS—SVM model was developed for the variety discrimination. This model was compared with EW—BP-ANN model by using back-propagation artificial neural network (BP-ANN).Results showed that the same recognition accuracies (100% for the calibration set, 93.3% for the validation set) were obtained for EW—LS—SVM and EW—BP-ANN models, respectively. Studies show that it is feasible to use EW—LS—SVM model for the variety discrimination of pears.

Abstract:In order to promote the application of low-temperature pasteurization in the heat thermosensitive materials, the equipment was designed. The design principle, its structural characteristics and processes were proposed, and the thermal power, heat transfer and flow resistance were analyzed. The maximum processing capacity was 13800mL/h with 230mL/min of maximum flow velocity. Taking water as treatment material, the temperature of water can reach to 52℃ from 4℃ in 4.5s, and reduce to 20℃ from 52℃ in 3s or 10℃ in 6s. And the bacterium concentration of liquid egg white could lessen to 100CFU/mL in 2.5min at 55℃. The performance test shows that the system possesses a good heat-transfer capability, and a high sterilizing effect. Results provide the technical basis for the design and manufacture of low-temperature pasteurization equipment.

Abstract:The effect of ultra high pressure (UHP) treatment on conformation of S-ovalbumin was studied with Raman spectra and fluorescence spectra analysis. The effect of UHP on some functional properties of S-ovalbumin, such as solubility, emulsibility and foamability, were also investigated. It was showed that no significant changed in the molecular weight distribution of S-ovalbumin after UHP. Along with the increase of pressure, the content of random coil of S-ovalbumin was increasing gradually, the stability decreasing owing to the conformation change of disulfide bonds, and tyrosine was buried in the side chain, accordingly the compactly plate sheet structure was to become loose. The fluorescence intensity showed a slight increase after UHP under 100MPa, but then a sharp decline with the increase of pressure, no shift of the fluorescence emission peak happening, so it was pointed out that UHP induced conformational change. The solubility, emulsibility and foamability properties of S-ovalbumin had been improved significantly with the increase of pressure, and achieved the best effect at 300MPa. Then, there was a drop down when the pressure was 500MPa.

Abstract:Glucose was used as an agent to modify soybean 7s globulin, in order to prepare for three glycation products of soybean 7s globulin. Rotary rheometer, texture analyzer and scanning electron microscope were used to analyze rheology, texture and microstructure of soybean 7s globulin and its glycosylation product gel, in order to study the effect of glycosylation reaction on 7s globulin gel. Research results showed that glycosylation reaction could improve the thermal stability of soybean 7s globulin and move up the soybean 7s globulin gel point. The viscoelasticity of the soybean 7s globulin gel was increased. The sugar chains could promote the formation of the soybean 7s globulin gel network.

Abstract:With the aim to improve the yield of rice bran polysaccharide, the method of extrusion in conjunction with ultrasound was used. On the basis of single factor experimental results, the combination design of quadratic orthogonal rotation was adopted to analyze the conditions of extrusion process and ultrasonic treatment condition, and then the mathematical model of ultrasonic treatment was constructed. The test results show that the rice bran is acquired under the condition of moisture content 20%, extrusion temperature 115℃ and screw speed 120r/min, the yield of rice bran polysaccharide can reach to 7.18% under the optimized conditions of ultrasonic time 21min, ultrasonic power 117W, ultrasonic temperature 72℃ and liquid-solid ratio 8.7mL/g.

Abstract:Some kind of audible sound can help plants or animals to grow healthily and faster. However, the acoustic waves was hard to be produced accurately as they would be absorbed or reflected back and forth in controlled environments such as greenhouse, plant factory, or aquaculture factory. A solution for improving audible sound output based on a closed-loop feed-forward control method was proposed. The output sound can be corrected by updating the transfer function of sound generation system. Proof tests were conducted in an artificial climate cabinet with 1.2m×0.53m×0.9m. The results showed that pure tones, combination sound of pure tones, and normal music can be produced with over 98% output accuracy.

Abstract:Closed-loop control system of greenhouse temperature was established for multi-index optimization by CFD modeling. In the system, multi-index including average temperature, temperature distributed and control cost, and control scene was natural ventilation. In order to minimize these indexes under the control mode, the GA optimization algorithm was adopted to obtain the optimal control outputs (entrances and skylights amplitudes). Simulation experiment shows that the technique of CFD for model can hold whole greenhouse environment into one system to improve control accuracy, and the control objective by CFD model is a “field”, not a “point” as tradition. Meanwhile, using GA algorithm can get the optimal control inputs in multi-index system for reducing regional difference and energy consumption synchronous, so this design technique can richen the technology in greenhouse control system.

Abstract:According to the existing problem of breeder continuous observing sows’behavior for sow farrowing judgment, working hard, piglet death due to negligence, monitoring system of sows’behavior before farrowing based on three axis acceleration sensor and WSN was designed. Sows’activities information was collected by using wireless acceleration sensor node. According to different acceleration curve volatility, behavior type was classified by K-means clustering algorithm, displayed real time and wireless transferred by 3G. The experiments showed that the system could acquire and transfer sows’activities information in no time, and the typical behaviors consist of lying, standing, eating and nesting were detected correctly. The accuracy was 87.93%. The system worked stably.

Abstract:In order to improve the accuracy rates and lower the impact on fruit recognition in unstructured environment, a combination of PMD camera and color camera was used to capture multi-source images of orchard scenes, SURF algorithm was used for extracting scale invariant features, Euclidean distance was regarded as a measure for judging the similarity of features, the ratio of distance from the closest neighbor to the distance of the second closest was utilized for initially matching feature vectors, BBF algorithm was devoted to speed up the closest neighbor’s query, a kind of iterative method between picking out outlier points and optimization of model was applied to purify results, the performance of image registration was evaluated according to the MSE, NMI and COEF. The different experimental results show that the amount of information locking to object are enriched by the combination of cameras, the hybrid algorithm is real-time, robust and has ideal precision, which meets the need of orchard test.

Abstract:Parameters of pulse coupled neural network(PCNN) were simplified and adaptive to determine. Spatial information and gray information of image were coupled to the weighted connection coefficient for greenhouse cucumber segmentation by using the 2-D Tsallis entropy to select the best results of iteration. Experimental results showed that, methods of contrast and regional consistency were employed to evaluate effect of different segmentation. Segmentation results of prospered method was better than using Shannon entropy and minimum cross entropy to terminate iteration of standard pulse coupled neural network segmentation.

Abstract:Growth mechanism and visualization model of lily scale was developed. According to growth mechanism of scales whirling and packing, the system of bulblet growth and visualization was constituted. The scales’ growth was regarded as linear growth trend, when growing a little elements, the scale deflected a certain angle to center-stem. Scales’ visualization model was developed by employing quadrilateral picture element drawing double-semi-elliptical truncated cone. The section drawing of scale was crescent, which was composed of two semi-ellipses of identical semi-major axis and unequal-semi-minor axis. The result shows that this system can simulate livingly lily bulblet vegetation process of whirling and packing.

Abstract:Machine vision inspection of white foreign fibers in cotton is a research hotspot in China and aboard. Based on the fact that there are flosses and free filaments on the surface of a cotton layer，and most of the white foreign fiber surfaces are smooth, without any floss， an image acquisition method of the cross-section of the samples under the illumination of linear laser was proposed, which showed the differences of the microstructure characteristic of their surface from the reflection and transmission of the linear laser. Then, according to the features of the distribution and density of the flosses around the white spots in the images, an algorithm for identification of cotton and white foreign fibers was suggested. The experimental results indicated that, by the new method, the detecting rate of the white foreign fibers in cotton was up to 86.9%.

Abstract:Based on the evaluation analysis of the energy characteristics of products, an energy optimization performance assessment model was presented taking into account economical effectiveness, environmental performance and uncertainty of energy consumption factors of use phase. In accordance with using process of energy optimization, the economy analysis model and environment analysis model were established. Uncertainty factors influencing energy optimization were analyzed and modeled during the usage stage. Therefore the evaluation value of energy optimization performance was obtained. Then the product design scheme was evaluated by applying fuzzy information axiom method, and the optimal design scheme was acquired. At last, a product case was given to verify the assessment method.

Abstract:Based on the pseudo-rigid-body model (PRBM), a PR pseudo-rigid-body dynamic model (PRBDM) subjected to a force at the end was developed considering the effects of transverse deformation and axial deformation of flexible elements in compliant mechanisms comprehensively. The dynamic equation of the PR PRBDM was derived by using the Lagrange equation. The changes of performances of the PR PRBDM were showed in the equation feature and dynamic responses. The numerical analysis results indicate that the PR PRBDM proposed can be used to show the real dynamic characteristic of compliant mechanisms by introducing a prismatic pair to simulate the axial movement of flexible elements in compliant mechanisms and was suitable for the dynamics analysis and design of compliant mechanisms.

Abstract:In order to solve multi-objective optimization problem of the hydrodynamic sliding bearing, a modified multi-objective differential evolution algorithm (MMODE) was proposed. The proposed algorithm provided a modified differential vector selection mechanism to improve the convergence speed and a population pruning strategy to maintain the population diversity. The vector selection mechanism compared two selected individuals and used the non-dominated individual minus the domination individual. Compared with several other evolutionary algorithms, the results showed that the proposed algorithm could overcome the premature convergence efficiently and had better convergence and diversity metrics. The results of engineering example showed the feasibility of the proposed algorithm.

Abstract:The synthesis of mechanism the disc cam mechanism with oscillating follower has not been completed satisfactorily. The synthesis was solved completely by introducing a concept of auxiliary parallel line family based on the principle of analogous velocity chart. The left and right end points of intersection of the auxiliary parallel lines and the lines which limited the axis position of cam were solved. Through this method, the boundary points and lines of the axis position of cam were achieved in theory. Then the accurate analytical solution and the numerical discretization method for solving the points and lines were presented. According to this method, the minimum sizes of the base circle radius and the length of pendulum can be derived directly and the allowable selected area of the axis position of cam can be presented. The synthesis of the disc cam mechanism with oscillating follower is completed satisfactorily. The mechanism design example shows that this method is corrected and effective.

Abstract:Due to the problems of temperature-sensitive point selection and model establishment in the modeling of CNC machine tools thermal error compensation, the method was presented by combined with fuzzy clustering and grey correlation to select temperature-sensitive points and the autoregressive distributed lag was used to establish model. According to the experimental data of machine temperature and thermal error, multiple regression model and autoregressive distributed lag model were built respectively. The modeling test of thermal error was designed on the Leaderway V-450 CNC machining center, the thermal error and temperature data were measured on the conditions of the spindle speed in 2000, 4000 and 6000r/min. The result showed that fitting accuracy of distributed lag mode was better than that of multiple regression model, robustness of distributed lag mode was lower than that of multiple regression model when experimental data of any spindle speed was used to modeling, but the robustness of distributed lag mode was prior to multiple regression model when experimental data of any two spindle speeds were used to modeling. Application of autoregressive distributed lag model for CNC machine tools thermal error prediction can be useful.

Abstract:Based on a rigid plastic finite element method, the surface defect of closed precision-forging process for shifting gear blank can be predicted. The metal forming process with different drafting angle and fillet radius in the die key part was simulated by using the orthogonal experimental method, and the initiation of surface defect was analyzed in detail. The reasonable forging critical diagram of shifting gear blank was given, which effectively eliminates fold and unfilled. Meanwhile, in view of the problems of the high position accuracy of ribs and the high forming load in actual practice, a new scheme of divided flow precision-forging was put forward, which can greatly improve rib position degree precision and reduce load. The accuracy of position degree was less than 0.08mm, and the reduce load was reduced by 20%~40%. The new scheme was put into actual practice and the key problems of a closed precision-forging process for shifting gear were solved. The reliability of the numerical simulation was verified.

Abstract:An improved model of tangential contact stiffness for joint interface was put forward by using anisotropic fractal geometric theory. Numerical simulation was executed to visually attain the complex nonlinear relationships between joint interface tangential contact stiffness and normal load, tangential load, fractal dimension D, fractal roughness G, relating factor K and material property φ. The numerical simulation results indicate that the joint interface tangential contact stiffness increases with increasing normal load, relating factor K or material property φ, but decreases with increasing tangential load or fractal roughness. When fractal dimension is smaller, the joint interface tangential contact stiffness increases as fractal dimension increases. However, when fractal dimension becomes larger, the joint interface tangential contact stiffness decreases as fractal dimension increases.