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Banana stem is a known alternative to wood for the production of pulp and paper. During the production of paper, it is extremely important to save costs and time while at the same time enhancing quality of produced paper. In the present study, paper was developed from banana stem fiber by optimizing its density. Response surface methodology (RSM) using Box-Behnken design (BBD) was used to determine optimum blending parameters of the developed papers. The influence of banana stem fiber amount (250-1000 g), water amount (1-2liters) and blending time (5-10 min) on paper density was ana)lyzed using software Stat-Ease 360, Version 13. The optimum conditions of banana stem fiber amount, water amount and blending time to achieve a density of 675.75 g/m3 were determined as 461.83 g, 1.31liters, and 8.53 min, respectively. ANOVA results revealed that the quadratic model best fits the density response, with blending time and banana stem fiber amount as the most significant model terms. Linear effects were more predominant than quadratic and interaction effects. The developed density model was in close agreement with experimental findings with an R² value of 0.9748. Developed paper had cellulosic contents, with volatiles as high as 82.11%wb and 2.11% wb ash composition. Future works on thermal properties of paper are encouraged. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to get high efficient cellase-producing bacteria and determine the taxonomy. [Method] Sodium carboxymethylcellulose was selected as the sole carbon source to isolate cellulose-producing microorganism. A total of 51 bacteria and actinomyces were isolated from natural fermentation material of tobacco straw.Nine isolates possessed high cellulase activities in congo dye experiment. The phylogenetic relationships of cellulase producing bacteria and actinomyces were determined through the analyses of phylogenetic trees constructed using 16 S rRNA gene sequences. [Result] Luteibacter sp.L43 possessed the highest cellulase activities in enzyme activity tests. The effects of the single factor including pH, carbon and nitrogen concentration on filter paper enzyme, endo-β-1, 4-glucanases and exo-β-1, 4-glucanases for L43 were determined.Under the condition of pH6, sodium carboxymethylcellulose concentration 12.5 g/L and NaNO3 concentration 5 g/L, the highest cellulase activities of endo-β-1, 4-glucanases and exo-β-1, 4-glucanases of L43 were 16.9 and39.62 U/mL, respectively. [Conclusion] This study provided a good cellulose producing bacteria for tobacco straw fermentation and laid a foundation for the development and utilization L43. [ABSTRACT FROM AUTHOR]

The mobile flume has the advantages of not easy to be silted up and can be moved and reused in many places, etc. Compared with the fixed type, the streamlined shape of the measuring flume has good hydraulic performance, and the diffusion section of the flume has a great influence on the hydraulic performance, however, there is a lack of research on the design principle and method of the diffusion section at present. In order to study the influence of flume structure on hydraulic properties, and to provide theoretical guidance for the design of streamlined flume structure, This paper establishes a D40Ushaped channel simulation model, and then uses FLOW-3D to simulate the semi-elliptical with semi-elliptical, semi-elliptical with parabolic, semi-elliptical with arc, semi-elliptical with Myring curve, and fish-shaped flume under flow rates of 35, 45, and 55 L/s. Furthermore, the accuracy effect of numerical simulation is verified by prototype test, and then the design principle and method of diffusion section are discussed. Finally, based on the isight platform, the semi-elliptical with Myring curve and fish-shaped flume with better hydraulic performance are optimized. The results show that the relative error between the numerical simulation and the experimental water depth is 0.1%-1.3% and the relative errors of velocity in upstream, throat and downstream sections are 0.19%-6.63%, 0.06%-6.15% and 0.02%-6.22% at 45 L/s flow rate, respectively. The numerical simulation results have high accuracy. The Froude number in the upstream of the five flumes is less than 0.5, and the maximum backwater height is 5.71 cm, which meets the requirements of flow measurement accuracy and channel safety. Among them, the head loss and backwater height of the semi-elliptical with Myring curve flume are the lowest, the critical submergence degree of the semi-elliptical with semi-elliptical flume is the highest, and the Froude number is the smallest. The design principle of the diffusion section of the flume is: under the condition of slightly reducing the critical submergence degree, the first half of the diffusion section is designed as a curve with larger curvature to reduce the upstream backwater; the second half is designed as a curve with opposite curvature and smaller curvature to improve the flow state, smooth the water flow and reduce the head loss. After optimization, the curvature of the first half of the semi-ellipse with Myring curve and the fish-shape flume increases, and the curvature of the second half decreases, the backwater and Froude number are reduced, and the head loss is reduced by 5.5% and 6.3%, respectively. The study can provide theoretical guidance for the design and optimization of streamlined measuring tank structures. [ABSTRACT FROM AUTHOR]

The research progress on simulation and optimization of pressure swing adsorption purification technology for low concentration coal is reviewed. The adsorbent and pressure swing adsorption process are briefly and clearly introduced. From the perspective of the development trend of adsorbents, simulation and optimization can improve the performance of adsorbents and the ratio of raw materials, and improve the effectiveness of adsorbents. From the perspective of the development trend of pressure swing adsorption, simulation and optimization of pressure swing adsorption equipment can make its automation effect better and economic benefit higher. This paper summarizes and points out that simulation and optimization play an important role in this technology from both perspectives, which improves the efficiency and productivity. While bringing a lot of convenience to the technology, there are also areas for further improvement from both perspectives. From the perspective of adsorbent, the simulation and optimization of multicomponent mixtures still need to be improved; from the perspective of pressure swing adsorption, there are still limitations in the dynamic change simulation in the actual operation, and the safety optimization in the operation of the device should be considered more. [ABSTRACT FROM AUTHOR]

With the increasing awareness of citizen copyright, more and more images containing watermarks are appearing in daily life. However, existing research shows that images with watermarks can cause neural network misclassification, posing a significant threat to the popularization and application of neural networks. Adversarial training is one of the defensive methods to solve this problem, but it requires a large number of watermark adversarial samples as training data. To address this issue, this paper proposes a visible watermark adversarial attack method based on intelligent evolutionary algorithm to generate high-intensity watermark adversarial samples. This method can not only quickly generate watermark adversarial samples, but also maximize the attack on the neural network. In addition, this method incorporates image quality evaluation metrics to constrain the visual loss of the image, making the watermark adversarial samples more visually appealing. The comprehensive experimental results show that the proposed method has lower time complexity than the benchmark watermark attack method, and has a higher attack rate on neural networks compared to the benchmark black box attack. [ABSTRACT FROM AUTHOR]

In the social environment of "carbon peak and carbon neutralization" and the economic environment of "carbon cost", renewable energy with the attribute of zero carbon + low cost has become an important decision-making factor for data center operators to carry out multi-objective management through load scheduling under various internal and external constraints. This paper analyzes the potential and mode of cooperation between renewable energy and data center operation and management, and introduces the data center load scheduling optimization method based on renewable energy consumption. Finally, this paper analyzes, summarizes and compares the data center load scheduling methods based on renewable energy consumption from three aspects: space-based scheduling optimization, time-based scheduling optimization and space-time scheduling optimization. [ABSTRACT FROM AUTHOR]

The current study investigated the Ethiopian sugarcane bagasse during its delignification using the Kraft pulping process and bleaching by single stage hydrogen peroxide process. The multilevel categoric experimental design was used to appraise the effects of the independent process variables (temperature, NaOH concentration, and time) on the pulp yield and kappa number during the Kraft pulping process. The central composite experimental design of response surface methodology was used to appraise the effects of independent bleaching variables (bleaching temperature, H2O2 concentration, and time) on the pulp yield, brightness, and whiteness during the bleaching process. The optimal pulp yield was 38.41% with 17.68 kappa number. The bleached pulp yield for the pulp with kappa number of 17.68 and the pulp with kappa number of 8.41 were 84.12% and 83.91%, respectively. The brightness and whiteness for the pulp with kappa number of 17.68 were 61.92% and 85.36%, respectively. Similarly, for the pulp with a kappa number of 8.41, the brightness and whiteness were 68.35% and 91.43%, respectively. Paper from the pulp with kappa number of 17.68 has higher tensile, burst, and tear strength. The study shows the promising utilization of the Ethiopian sugarcane bagasse for paper production via the Kraft delignification and single stage hydrogen peroxide bleaching. [ABSTRACT FROM AUTHOR]

Reasonable power equipment operation and maintenance schemes are critical for lowering life cycle costs and increasing equipment reliability. In order to formulate a reasonable preventive maintenance scheme to the circuit breaker life cycle cost, this paper describes a method for optimizing the life cycle cost of circuit breakers based on the MBWO (Multi-strategy Black Window Optimization Algorithm, MBWO). The influence of different maintenance methods on the interruption cost is considered when establishing the life cycle cost model, first of all. Second, taking the circuit breaker's reliability and preventive maintenance degree as constraints to construct the minimum objective function, the results are compared with other algorithms. A practical example proves that MBWO has a good convergence speed. It can further reduce the life cycle cost of circuit breakers and improve the reliability of equipment, which provides a reference for the formulation of preventive maintenance schemes for the circuit breaker. [ABSTRACT FROM AUTHOR]

In this paper, an ultrasonic method has been developed to achieve a cleaner washing process for denim fabrics. At first, a comparison study was established between a conventional and an ultrasonic washing processes. Effects of reducing agent and sodium hydroxide concentrations, washing temperature and washing duration parameters were studied. Then, a factorial design was dressed to model the ultrasonic process. Regression equations for the color strength reduction Δ(K/S), lightness difference ΔL* and tensile force F(N) of washed denim fabrics were established. As results, efficience of ultrasonic process has been proven, fade appearance was obtained without degrading the textile material under several washing conditions. Hence, for a frequency of 25 kHz and a power of 300 W, and according to the degree of fade appearance of denim fabrics target, optimal ultrasonic washing conditions would be selected within these proposed intervals: a sodium hydroxide concentration lower than 15 g.L−1, a reducing agent concentration lower than 6 g.L−1, a washing temperature ranging from 50°C to 70°C and a washing duration ranging from 5 to 30 minutes. Finally, certain comfort properties of washed denim fabrics were evaluated. Both conventional and ultrasonic washing processes have been found to lead to similar thermal comfort properties. [ABSTRACT FROM AUTHOR]

Aiming at the limitation of electric vehicle power to driving distance, this paper established a user reservation distribution model to obtain the order distribution result when profit was biggest. This kind of problem belongs to NP-hard problem, which is difficult to solve. The refore, this paper designed a new discrete electromagnetic field optimization algorithm to solve it. Base on the basic electromagnetic field optimization algorithm, it used the binary coding mode to change the particle movement mode, and for the negative electromagnetic field it added update process to the electromagnetic particles. Compare with genetic algorithm, binary particle swarm optimization, improved binary cuckoo search algorithm and binary lion swarm optimization, numerical experiments show that the new algorithm has high er computational efficiency. In addition, compare with the traditional distribution model, the new order distribution model can obtain higher profits, indicate the effectiveness of the model. [ABSTRACT FROM AUTHOR]

This paper considered a wireless communication network with multiple UAV base stations and multiple users.In the network,due to the limited spectrum resource,the backhaul links of the UAV base stations and the data links of the users shared the same spectrum.In order to use the spectrum resource efficiently and improve the communication performance of the users,this paper jointly optimized the bandwidth and power of the backhaul and data links as well as the flight trajectory of the UAV base stations,to maximize the minimum average rate of all users.This joint optimization was subject to the UAVs’ mobility,the total spectrum bandwidth,and the total transmit power,and the involved joint optimization problem was non-convex,thus it was difficult to find the optimal solution.This paper proposed an efficient algorithm to obtain a high-quality suboptimal solution of it.Simulation results show that the minimum user rate achieved by the proposed joint optimization algorithm is significantly higher than that of the benchmark schemes. [ABSTRACT FROM AUTHOR]

Coir is a lignocellulosic fiber which is quite preferable in the production of biofuels and chemicals. Conversion of cellulose and hemicellulose to biofuels requires five main unit processes out of which, pretreatment plays a major role because all subsequent processes depend upon the pretreatment results. Partial degradation of lignin, hemicellulose, and breakdown of the sugars also occur during the pretreatment of the coir. So, the optimal condition selection is vital. In this paper, an attempt has been made to optimize the parameters (time, NaOH concentration, and temperature) by Box-Behnken design in order to get the optimum level of lignin, hemicellulose, and cellulose. To obtain an ideal solution, the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) is used to rank the optimized solutions. Further, to find the authenticity of TOPSIS, the top three ranked solutions are again tested. It is observed that error percentage increases with an increase in rank order. [ABSTRACT FROM AUTHOR]

Quantum do ts (QDs), as typical inorganic fluorescent nanomaterials, have broad application prospects in the fields of optoelectronic devices, new luminescent materials, and biomedicine. In this paper, a very simple one-pot method was adopted to synthesize CdTe QDs stabilized by mercaptosuccinic acid (MSA) in aqueous phase. Cd Te QDs were prepared by using the stable sodium tellurite a s the Te source, cadmium chloride as the Cd source, mercaptosuccinic acid as the stabilizer, and sodium borohydride as the reducing agent. The effects of reac tion condi tions such as the pH of the precursor solution, the molar ratio of Cd/ Te, and the molar ratio of Te/ BH4 - on the 1 uminescence properties of Cd Te QDs were discussed. The optical properties of CdTe QDs synthesized under different conditions were compared and analyzed by fluorescence emission spectroscopy and ultraviolet-visible spectroscopy (UVvis). The results show that the fluorescence performance of the prepared Cd Te QDs is the best when the precursor solution pH is 6, the Cd/ Te molar ratio is 1 /0. 2, and the Te/ BH4 - molar ratio is 1/26. 5. In addition, CNC/ CdTe QDs fluorescent nanocomposite films were prepared by using nanocrystalline cellulose (CNC) as the carrier and MSA-CdTe QDs as the fluorescent object. The different films showed higher saturation of green, yellow, orange and red fluorescence, which are sharp contrast with their colors under natural light. As the simple preparation method, low cost and low toxicity, it is expected to be used as a new type of green laser anti-counterfeiting label in the field of anti-counterfeiting. [ABSTRACT FROM AUTHOR]

Fulvic acid is a kind of water soluble humic acid with low molecular weight, dense functional groups and strong physiological activity. In this paper, the strain, which can utilize the black humic acid to produce the fulvie acid, was screened and characterized based on the physiological and biochemical properties and 16S rDNA sequence analysis. Besides, the fermentation medium was optimized by single factor experiment. The results showed that the obtained strain A1 was identified as Bacillus licheniformis. When the strain was cultured in the optimized medium containing 20 g/ L black humic acid, 15 g/ L glucose, and 10 g/L peptone, for 24 h (37 'C, 200 rpm, 1% inoculation), the final content of fulvic acid reached 23. 02 % . This paper provides a theoretical basis for the study and application of biotransformation of fulvie acid. [ABSTRACT FROM AUTHOR]

Cotton is an important strategic material. With the increase of cotton planting costs, improving the level of mechanized harvesting has become an important way to improve the economic benefits of cotton planting. The main cotton harvesting machinery used in China is the horizontal spindle type cotton picker. In the process of production practice, the domestic cotton pickers have problems during high-speed operation, such as improper matching of picking speed ratio coefficient, badly gear worn and poor reliability of picking head transmission system. In view of the above problems, this paper optimized the transmission system of picking head based on the comprehensively consideration of the operating speed, transmission system reliability, operation quality and other factors, aiming to increase the operating speed of the cotton picker, improve the reliability of the picking head transmission system and the operation quality of picking head. According to the structure and working principle of the horizontal spindle type cotton picking head, the transmission route and transmission ratio of picking head transmission system of cotton picker were analyzed and calculated firstly. Then, the picking mechanism and picking conditions, such as the range of picking speed ratio coefficient of cotton picker, the actual number of turns needed to pick cotton petals and the picking time of spindle, were determined through virtual simulation technology and theoretical analysis and calculation. Meanwhile, the roller power gear in the transmission system of the picking head was selected as the optimization object, the tooth number of roller power gear, modification coefficient of the upper gear on clutch, modification coefficient of roller power gear and addendum height coefficient were selected as design variables, and the objective function and constraint conditions were established. The Genetic algorithm and 1stOpt software were used to optimize the transmission system of picking head. The optimization results were as follows: the number of teeth for the roller power gear was 72, the modification coefficient of the upper gear on the clutch was -0.14, the gear modification coefficient for the roller was 1.208, and the addendum height coefficient was 1.25. A cotton picking performance test bench was built combining the operation requirements of the cotton picker. The operation performance of picking head before and after optimization was verified on the test bench with the factors as follows: picking roller speed was 113-143 r/min, the operation speed was 5.93-7.20 km/h. The results showed that the working speed of the picking head was increased from 6.4 to 7.2 km/h, increased by 3.6%, and the work efficiency increased from 4.86 to 5.47 hm²/h, increased by 12.5%. Under the working speed of 7.2 km/h, compared with before optimization, the collection rate increased from 90.4% to 93.7%, increased by 3.6%, and the impurity rate decreased from 10.28% to 9.72% and decreased by 5.4%, which verified the rationality of the optimization of the picking head transmission system in this paper. The study can provide a reference for the development of picking head of cotton picker. [ABSTRACT FROM AUTHOR]

In mechanized plug seedling production, it is necessary to eliminate inferior plug seedlings and replant healthy plug seedlings with transplanter. In order to improve the plug seedling transplanting efficiency, plug seedling transplanting path would be planned. In this paper, the Clone Selection Algorithm(CSA) model and Immune Genetic Algorithm(IGA) model were constructed to solve the problem of transplanting path optimization of plug seedlings in greenhouse. Compared with the fixed sequence method and the Genetic Algorithm(GA), the simulation and verification tests of the transplanting path planning were carried out with 50-hole, 72-hole, and 128-hole plug trays. Set the population size in the CSA model to 40, the mutation probability to 0.4, and the number of clones to 10. Set the total population size in the IGA model to 40 (of which the memory cell bank capacity was 10), and the crossover probability to 0.5, the mutation probability was 0.4, and the diversity evaluation parameter was 0.95. The results showed that CSA and IGA model designed in this paper could achieve the purpose of optimizing the plug seedling transplanting path. The planned path length of the two models was similar, and the planned path length of two models was significantly shortened compared with the common sequence method and the GA. In the verification tests, the planned path length of common sequence method, GA model, CSA model and IGA model were 52 998, 50 807, 48 977 and 48 945 mm respectively. Compared with the common sequence method and the GA, the planned path length of CSA model and IGA model were shortened by 7.59% and 7.65%, and shortened by 3.60% and 3.66% compared with the GA model. The path planning efficiency of IGA model was higher than that of the CSA model, the calculation time of GA model, CSA model and IGA model was 3.23, 5.86 and 2.72 s respectively, the calculation time of IGA model was 15.79% less than that of the GA model. The models designed in this paper were suitable for path optimization of various-size plug seedlings automatic transplanting in greenhouse, it only needed to get the coordinates of plug seedlings according to the actual needs. [ABSTRACT FROM AUTHOR]

(1) Background--The agricultural and forestry biomass power generation industry is a typical emerging industry'. It is highly valued by all levels of the department. Therefore, they have implemented support policies such as electricity price subsidies. Since the subsidy policy implemented, the agricultural and forestry' biomass power generation industry' has developed a lot, but the development rate is still slow. The industry still has problems such as low farmers' participation and imperfect enterprise development. Can the current electricity price subsidy really promote this industry? (2) Methods--From the perspective of subsidy policy of biomass energy price, this paper used the system dynamics method to build a simulation model of agricultural and forestry biomass power generation industry' integrating government, enteiprises, middlemen and farmers with Vensim DSS tools. Then, based on the existing policies, this paper designed different policy scenarios and compared the effects of different policy scenarios based on the field survey data of typical enterprises, middlemen and farmers in the agricultural and forestry biomass power generation industry during 2017-2018, so as to evaluate the implementation effect of China's forest biomass power generation industry' policy, and to optimize the policy according to the limitations of the existing policies. (3) Results--The results show that compared with the no-policy scenario, the current subsidy policy can slow down the loss rate of agricultural and forestry biomass power generation enterprises, and increase the net profit of the industry'. However, the current subsidy is not effective for farmers and intermediate entities, and because the policy amount is too small, it is impossible to fundamentally reverse the loss status of power generation enterprises. If the policy is implemented according to the current method, the enterprises' loss rate will increase and the net profit of the industry will also drop sharply when the subsidy implementation period ends and the release is stopped. Therefore, the implementation quota and implementation method of the current subsidy policy are not conducive to the development of the entire industry'. Through the simulation of different policy scenarios, it is found that if the subsidy quota is increased to 0. 573 yuan/kWh, and the 2% subsidy withdrawal method is adopted, the overall profits of each main body and industry' can be increased. (4) Conclusions and Discussions--Through the comparison of different policy scenarios, the policy optimization plan is as follows; Increasing the subsidy quota appropriately and adopting the 2% subsidy withdrawal method. Combined with the huge subsidy gap and financial budget constraints in China, the following suggestions are proposed: (1) To guide and implement diversified investments to broaden funding sources and establish multi-channel financing mechanisms; (2) To designe the biomass subsidy withdrawal mechanism to improve policy efficiency, and adhere to the principle of "focusing on planning, approval, and supervision"; (3) To increase the subjects of policy incentives and appropriately grant subsidies to middlemen and farmers in accordance with certain standards; (4) To reduce the cost of transportation links and raw material processing; (5) To promote the renewable energy quota system and the construction of the green certificate trading system. [ABSTRACT FROM AUTHOR]

With the growth of population and the rapid development of social economy, the shortage of water resources and the pollution of water environment in Yanghe River Basin have become increasingly prominent, which leads to the water quality in the assessment section of Yanghe River Basin is difficult to meet the water quality standard. In order to achieve the efficient utilization of water resources and environmental protection, combining with the characteristics of economic development and water resources utilization, an optimal allocation model of agricultural water resources was established with the water quality constraints for Yanghe River Basin. Therefore, under the premise of the water quality of assessment section, the monthly water allocation of different crops and livestock, as well as the crop planting area and the livestock number were optimized to maximize agricultural economic benefit. The paper proposed a method to control water quality by supplying water and reducing pullution simultaneously. Moreover, based on the water water requirement of agriculture and animal husbandry, this paper introduced a method to avoid unbalanced water supply problems and reduce the dimension to improve the solution efficiency. The optimization results showed that the assessment section of the Bridge 8 could be adjusted to meet the water quality standard by increasing the planting area of the vegetables and the tubers with higher benefit, as well as the large livestock number, and decreasing the planting area of oilseeds with severer emission, as well as the small livestock number. Comparing with the actual values in 2014, the agricultural water allocation decreased by 3.38%, and the economic benefit increased by 11.96%. Therefore, the model was verified effectively. Furthermore, the paper analyzed the optimization allocation schemes under different conditions of the low, median and high flow years in 2020. The results showed that, the more water quantity available, the more agricultural water allocation and river recharge correspondingly. In this condition, water allocation of most water users and subzones were also increased, of which Huailai and Xuanhua had larger increments. Besides, the water allocation of crops was larger than that of livestock, and the grains and fruits had larger increments. The increase rate of water users was relative to planting area, while the increase rate of subzones was relative to the crop type and planting area, and water allocation was the comprehensive tradeoff among available water for agriculture, pollution emissions and economic benefits. The proposed model is of great significance for ensuring water quality safety and sustainable development of regional economy in Yanghe River Basin, and has a certain reference value for optimizing allocation of water resources considering water quantity and quality. [ABSTRACT FROM AUTHOR]

Robot has been increasingly used in weeding. Taking the quadruped laser weeding robot as an example, this paper presents a method to optimize its four legs using the dynamic scale synthesis. The objective of the optimization was the lengths of the legs, in which, prior to optimizing the driving torque of the joint in each leg, we first optimized the driving torque of the leg based on the load it was required to take. The laser weeding robot used compound cycloid trajectory to plan its trajectory, which is ready for optimizing the driving torque of the joint in the rear leg. The optimization focused on the driving force moment on both the thigh joint and the calf joint, for which obtained a set of optimal thigh bar lengths and calf bar lengths. We first calculated the foot trajectory and the gait parameters of the robot, and then used the thigh joint force moment, the calf joint driving force moment and different leg rod lengths to maximize the dynamic target; the dimensional parameters of the legs were also taken as design parameter in the multi-objective constraint optimization. After the thigh joint driving force moment and the calf joint driving moment were firstly optimized using the particle group algorithm, the maximum torque of the leg joints within the each group of the rods was calculated under a given target trajectory by combining the leg sizes. Based on the smallest set of driving force moments, we found the maximum and minimum driving torque of each joint in the target trajectory, which was further optimized using the ideal dot method and the particle group algorithm. This transformed the multi-objective optimization to a single-objective optimization. These two-step optimizations allowed us to obtain the leg length in the group of optimal four-legged laser weeding robots. We verified the optimal results against experiments. The results showed that the optimized four-legged laser weeding robot significantly improved its dynamic performance compared to that without optimization. It was also found that the optimization reduced the maximum thigh joint driving force by 5.29% and the maximum driving force in the calf joint by 18.05%. The comprehensive methods presented in this paper cannot only help developing four-legged laser weeding robot prototype, but also provide references for studying driving force moment and energy consumption of four-legged robot. [ABSTRACT FROM AUTHOR]

Along with the continuous development of agricultural aviation application technology, an agricultural unmanned aerial vehicle (UAV) is widely used in modern agricultural production, which is the operation platform for implementing agricultural aviation technology. Due to the characteristics of simple operation, simple structure, easy maintenance and low cost, electric multi-rotor UAV is widely used in the field of agricultural aviation. However, it has the problems of small load capacity, short continuous operation time, low operation efficiency, etc. The multi-rotor single-arm tandem structure can effectively improve the load capacity and operation capacity of the electric UAV, but the structure will lead to the increase of the size and mass of the whole machine and reduce the effective utilization rate of energy, which still needs to be optimized and improved. Rotor spacing affects the overall performance of multi-rotor single-arm tandem electric UAV, but the influence of different rotor spacing on rotor lift of multi-rotor single-arm structure has not been studied. In this paper, by setting up a test platform and taking power consumption (P) and lift (F) as test indexes, the rotors with different spacing were tested, and the optimal spacing ratio between tandem rotors was analyzed and determined. The optimal spacing ratio was verified by theoretical analysis and flight test of solid aircraft. The lift performance and energy consumption of coaxial and tandem twin rotors at different spacing were tested. The results showed that the longitudinal spacing ratio had no effect on the lift performance, while the lateral spacing ratio had an effect on the lift performance. In order to further determine the optimal lateral spacing ratio, the variation law of rotor lift with lateral spacing ratio under the double rotor tandem arrangement was tested. When the lateral spacing ratio was less than 1.8, the lower rotor lift increased with the increase of lateral spacing ratio under the same power consumption. When the lateral spacing ratio was greater than 1.8, the lift of the lower rotor tended to be stable, and the average value of the lower rotor lift relative to the loss percentage of the isolated rotor was stable within 0.70%. When the lateral spacing ratio was equal to 1.8, the average loss percentage of the rotor lift under the tandem layout was 0.66% relative to the isolated rotor lift under different power consumption. At this time, the lower rotor lift is basically the same as the isolated rotor lift, thus determining that the optimal spacing ratio of the tandem double rotor was equal to 1.8. Secondly, by testing the variation of the lift force of two rotors with different sizes and the rotor lift force with the lateral spacing ratio under the tandem layout of multiple rotors, it was concluded that 1.8 was suitable for the tandem layout mechanism with different sizes and number of rotors. In order to validate the optimal effect of the lateral spacing ratio of 1.8 on the rotor spacing of the multi-rotor single-arm tandem electric UAV, this paper compared and analyzed the performance parameters of planar and tandem aircraft of six-axis 12-rotor UAV with multi-rotor single-arm structure. The results showed that compared with the tandem model with lateral spacing ratio 1.8, the fuselage size of the planar model increases by 38.70%, while the lift difference between the two is only 1.52%. Through flight tests, the results showed that under the same load, the hovering power per unit time of the planar model decreased by only 0.06%, while the fuselage mass increased by 6.82% compared with the optimized tandem model, the fuselage size increased by 38.7%. This paper studied the optimal rotor spacing of multi-rotor single-arm electric UAV. On the premise of ensuring the energy efficiency of the UAV, the rotor spacing of the multi-rotor single-arm structure electric UAV is optimized by changing the relative positions between the rotors, so as to optimize the fuselage size and mass, improve the aerodynamic characteristics of the multi-rotor single-arm structure UAV, reduce inertia, enhance payload capacity, and thus improve the overall performance. [ABSTRACT FROM AUTHOR]

Soft soil as a pavement subgrade leads to early pavement failure or increased pavement thickness. Ground improvement techniques have been used as a solution to this. The published studies on coir waste treated soft soil depict that the adverse volume change characteristics of clayey soils are mitigated by the resistance offered by coir waste. However, on analyzing, it can be seen that the engineering properties of coir waste treated soil are on a lower side. Hence, an additional stabilizer lime was used in combination with coir waste to investigate the enhancement in strength and reduction in deformation behavior. This paper presents the experimental studies carried out to investigate how the addition of lime to soil treated with coir waste affects various aspects like compression behavior, undrained shear strength, and deformation behavior. The degree of expansion and effect of the curing period was also analyzed and an optimized design model was arrived to quantify the strength in terms of lime content added to the coir waste treated soil and its curing period. Design charts for pavement thickness over treated subgrade soil were also developed. [ABSTRACT FROM AUTHOR]

This paper presents the use of Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method to determine the optimum time, NaOH concentration, and temperature for reduction in lignin content, reduction in flexural rigidity, and tenacity of the coir yarns using box-behnken design. Optimum conditions for better properties are obtained from the ramp graphs. The results indicate that the TOPSIS method is appropriate for solving the multi-criteria optimization of the process parameters based on ranking system. The optimal value for time, concentration, and temperature are 3 h, 5% NaOH, and 80°C based on the defined criteria. [ABSTRACT FROM AUTHOR]

This paper ostablishod secondary distribution model of optimization problem, aiming at fchfl minimum logistics eosl under optimal layout of I he workshop, and anl colony-genetic hybrid algorithm is used Lo solve quadratic assignment model. The hybrid algorithm combined Lhe advantages of the anl colony algorithm with the Kinetic algorithm, using the solution of ant colony system as the initial population of the genetic algorithm, overcoming the flaws of converging slowly, falling into the local optimum of the ant colony algorithm and easy to premature convergence of the genetic algorithm, which will achieve the global optimal model. This paper regarded a machine factory workshop as an example, using MATLA1J to solve the results, which shows that: it will save 10.0% logistics fees by using the new layout of genetic ant algorithm than the original program; while it is better and faster to use the hybrid algorithm to solve the shop I.nuni optimization problem than the .nil colony algorithm nv genetic algorithm. [ABSTRACT FROM AUTHOR]

Cotton stalk is an important renewable resource. China is rich in cotton stalk, if such a large amount of resources are recycled, it will produce huge economic benefits. But most of them are not recycled at present. In order to improve the mechanized recovery level of cotton stalk, study the influence of different parameters on the mechanized recovery of cotton stalk, and solve the outstanding problems such as high cotton stalk plucking rate and high cotton stalk leakage rate, this paper studied and designed a toothed disc cotton stalk harvester. The machine was consisted of suspension device, limit wheel, pull-out tooth plate, stalk discharge device, hydraulic motor, hydraulic pipeline and hydraulic control box. The key component of the machine was a toothed disc type stalk pulling device. During operation, the cotton stalk was lifted out through the toothed disc, and then the cotton stalk was discharged to the surface through the stalk discharge device. Leakage rate and plucking rate of cotton stalk were the main parameters to evaluate the performance of toothed disc cotton stalk harvester. In this paper, Box-benhnken central combination test method was used to study the working parameters of toothed disc cotton stalk harvester. Three-factor and three-level quadratic regression orthogonal test was designed. The three-dimensional model of response surface was established with the diameter of the toothed disc, the toothed disc speed ratio and the lifting height as the influencing factors. The influence of each factor on the quality of work was analyzed, and the influencing factors were optimized synthetically. The results showed that the lifting height and the toothed disc speed ratio had significant effects on the cotton stalk plucking rate (P< 0.01), while the lifting height, the diameter of the toothed disc and the toothed disc speed ratio had significant effects on the rate of cotton stalk leakage rate (P<0.01). The working parameters of the machine were deduced from the regression model optimization as follows: the lifting height was 66.2 mm, the diameter of the toothed disc was 627.59 mm, and the toothed disc speed ratio was 0.57. In November 2018, field test was carried out in the Yellow River Delta (Binzhou) National Agricultural Science and Technology Park. Test area was divided into 17 test plots, leakage rate and plucking rate of cotton stalk at each test plot were calculated. The results of the Daejeon experiment showed that when the lifting height was 70 mm, diameter of the toothed disc was 630 mm and the toothed disc speed ratio was 0.57, the cotton stalk plucking rate could reach 1.5% and the cotton stalk leakage rate was low to 3.0%. The test results showed that the theoretical results were coincident with the measuring results, and the error between them was less than 4%. The research results can provide references for the structure improvement design and operation parameters optimization of toothed disc cotton stalk harvester. [ABSTRACT FROM AUTHOR]

In most areas of Xinjiang, edible sunflower is harvested in stages by means of transplanting plates for drying and taking plates for threshing. In some areas, edible sunflower harvesters are used for field operations, and problems such as edible sunflower plate leakage and grain loss exist in the process of harvest, which seriously hinder the development of edible sunflower scale and industrialization. In order to solve these problems and improve the harvesting efficiency of edible sunflower machine, this paper conducted a field survey on planting mode and biological characteristics of the edible sunflower in Xinjiang, and summarized the harvesting mechanism of edible sunflower. Starting from the operation path of manual harvesting sunflower tray, and combining with the requirements of field harvesting, a kind of collecting station for edible sunflower was designed. Field experiment was carried out to verify the field performance of the collecting station for edible sunflower. The specific research contents and conclusions were as follows. First of all, experimental study on the physical characteristics of edible sunflower was made during harvest in Xinjiang. It mainly included the determination test of the basic physical quantity, the friction characteristic test and the impact seed falling test. The average moisture content of edible sunflower plate was 38.97% and that of culm was 65.49%. By the bevel method, we got the friction angle between the dish and the steel plate was about 29.2°, the static friction coefficient was 0.56. The experiments were carried out to obtain the operating parameters with less loss of sunflower plate, which provided the theoretical basis for the field operation of edible sunflower harvesting platform. Secondly, in this paper, the whole plan of the collecting station for edible sunflower was determined, and the structural design and parameter analysis of the key devices were carried out. This paper designed a kind of station for collecting edible sunflower by imitating the manual way of picking dish. The whole machine structure was mainly composed of the pick-up device, conveying device, collecting dish box, walking device, power transmission system and frame. By analyzing the segmented path map of manual picking-up and parabolic dish, and combining the working posture of the pick-up device in each harvesting stage, the bionic pick-up device was designed and the basic structural parameters were determined to achieve the goal of bionic dish taking action and the shortest parabolic dish path. The 3D model of the pick-up device was established and the kinematics analysis were carried out to obtain the displacement, speed and acceleration change rules of the pickup device's disk-bar and determined the best structure and working parameters combination of the pickup device. The conveying device was designed and the speed of it was calculated to be 92 r/min, the theoretical productivity was 2.19 t/h. By analyzing the power transmission system, we got the transmission law of chain. The field harvest test finally was carried out with the total harvest loss rate as the test index, the height of the plug plate, the rotational speed of the take-up rod and the forward speed of the unit as the test factors. The results showed that the collecting station for edible sunflower could complete the functions of picking up, transporting and collecting. The optimal combination of the collecting station for edible sunflower was that the height of the disc was 650 mm, the forward speed of the unit was 0.88 m/s, the rotational speed of the take-up rod was 23 r/min, and the total loss rate of harvest was less than 5%, which could meet the operation requirements of Xinjiang edible sunflower harvesting. [ABSTRACT FROM AUTHOR]

Cotton stalk is an important renewable resource. China is rich in cotton stalk, if such a large amount of resources are recycled, it will produce huge economic benefits. But most of them are not recycled at present. In order to improve the mechanized recovery level of cotton stalk, study the influence of different parameters on the mechanized recovery of cotton stalk, and solve the outstanding problems such as high cotton stalk plucking rate and high cotton stalk leakage rate, this paper studied and designed a toothed disc cotton stalk harvester. The machine was consisted of suspension device, limit wheel, pull-out tooth plate, stalk discharge device, hydraulic motor, hydraulic pipeline and hydraulic control box. The key component of the machine was a toothed disc type stalk pulling device. During operation, the cotton stalk was lifted out through the toothed disc, and then the cotton stalk was discharged to the surface through the stalk discharge device. Leakage rate and plucking rate of cotton stalk were the main parameters to evaluate the performance of toothed disc cotton stalk harvester. In this paper, Box-benhnken central combination test method was used to study the working parameters of toothed disc cotton stalk harvester. Three-factor and three-level quadratic regression orthogonal test was designed. The three-dimensional model of response surface was established with the diameter of the toothed disc, the toothed disc speed ratio and the lifting height as the influencing factors. The influence of each factor on the quality of work was analyzed, and the influencing factors were optimized synthetically. The results showed that the lifting height and the toothed disc speed ratio had significant effects on the cotton stalk plucking rate (P< 0.01), while the lifting height, the diameter of the toothed disc and the toothed disc speed ratio had significant effects on the rate of cotton stalk leakage rate (P<0.01). The working parameters of the machine were deduced from the regression model optimization as follows: the lifting height was 66.2 mm, the diameter of the toothed disc was 627.59 mm, and the toothed disc speed ratio was 0.57. In November 2018, field test was carried out in the Yellow River Delta (Binzhou) National Agricultural Science and Technology Park. Test area was divided into 17 test plots (each plots is 30 m×0.76 m), leakage rate and plucking rate of cotton stalk at each test plot were calculated. The results of the Daejeon experiment showed that when the lifting height was 70 mm, diameter of the toothed disc was 630 mm and the toothed disc speed ratio was 0.57, the cotton stalk plucking rate could reach 1.5% and the cotton stalk leakage rate was low to 3.0%. The test results showed that the theoretical results were coincident with the measuring results, and the error between them was less than 4%. The research results can provide references for the structure improvement design and operation parameters optimization of toothed disc cotton stalk harvester. [ABSTRACT FROM AUTHOR]

Grain loss rate is one of the most important performance index of corn head in mechanized harvesting. Seed harvesting is the main development direction of mechanized corn harvesting. The characters of seed harvesting corn variaty increased the urgency to reduce grain loss on corn head. The paper was proposed to solve the problem of grain loss on corn head. Theoretical analysis was conducted to the snapping process. Corn ear was subjected to pull force by the snapping rolls and the pull force transferred by corn stalk. Corn kernels were divided into 2 types due to their force condition. A kernel at the bottom end of corn ear was subjected to reaction forces by stripper plates, corn cob and the adjacent kernels and shear force by the pedicel. Kernels out of contact with the stripper plates were subjected to reaction forces by the adjacent kernels, pull force and shear force by corn cob. As the impact force was related to the impact time according to the theorem of impulse, the paper analyzed collision model between corn ear and stripper plates in the snapping process. A mathematical model was obtained about the impact time and intrinsic parameters of the system. The impact time was dependent on system mass, stiffness coefficient and damping coefficient, which lays on the mechanical structure and materials of collision objects. So, the impact force would decrease as the impact time could be prolonged by reducing the stiffness coefficient and raising the damping coefficient. The quantity of shed kernels could be reduced consequently. The paper proposed a corn head with wheel type rigid-flexible coupling snapping device to reduce loss. The corn head consisted of the frame, gear-box, snapping rolls, gathering chain, wheel type rigid-flexible coupling snapping device, and chain wheels. The wheel type rigid-flexible coupling snapping device consisted of snapping wheel axle, spring seat axle, supporting axle, buffer spring, and snapping wheel frame. Force analysis was conducted on the snapping wheel. According to the force conditions and dimension boundary condition, the structure diameters of snapping wheel, snapping wheel frame, and buffer spring were confirmed. In order to obtain the optimal parameters with the minimum loss rate of wheel type rigid-flexible coupling snapping device, the optimization experiments were conducted of the factors at 3 different levels. In the optimization experiments, the snapping wheel radius was designed at 10, 15 and 20 mm respectively, the flexible body thickness was at 2, 4 and 6 mm respectively, the snapping rolls rotating speed at 700, 800 and 900 r/min respectively. The Response Surface Analysis method was used to design the experiments. The software Design-Expert 8.0.6.1 was used to analyze the data. Regression equation was induced according to the experiment and analysis above. The optimal combination of wheel type coupling snapping device was as follows: The snapping rolls rotating speed was 700 r/min, the snapping wheel radius was 15 mm, the flexible body thickness was 4 mm. Verification contrast test was conducted between corn head with wheel type rigid-flexible coupling snapping device and the one with snapping rolls and stripper plates on corns at different moisture contents. As the kernels moisture contents were 21.8%, 16.7% and 13.4%, the grain loss rate decreased 53.4%, 48.6% and 47.0% respectively. This study provides not only theoretical basis but also design reference for the improvement of corn harvester design. [ABSTRACT FROM AUTHOR]

Simultaneous localization and mapping( SLAM) become a research hotspot in robot positioning and navigation.This paper elaborated the SLAM back-end optimization framework based on graph optimization from three aspects: optimization model, optimization algorithm and evaluation of results. In the aspect of modeling, this paper analyzed the modeling method based on dynamic Bayesian network, the modeling method based on factor graph and the modeling method based on Markov graph. In addition, it discussed the methods of back-end optimization, that is, least squares optimization method, relaxation optimization method, stochastic gradient descent optimization method and manifold optimization method. In the evaluation of the results, it described the evaluation of the results using χ2 error and MSE error. Finally, it made a prospect on the development of SLAM based on the current research hotspots. [ABSTRACT FROM AUTHOR]

Aiming at upgrading the regional industrial structure and achieving efficient use of water resources, this paper used relevant analysis theory and grey system theory to study the relationship between industrial structure and water consumption. On the basis of determination of the direction of industrial structure optimization, an industrial structure optimization model considering water carrying capacity was constructed, optimized the regional industrial structure under different level years, determined the industrial optimization scheme and analyzed them. The proportion of industrial structure in 2025 and 2030 will be 1.28:36.78:61.94 and 1.13:35.88:62.99, respectively. The model optimization results show that the optimized industrial structure of Zhengzhou in the future level years will improve the efficiency of water resources utilization. [ABSTRACT FROM AUTHOR]

In order to overcome the barriers on conducting field irrigation experiments including limited number of treatments and level setting, a large number of influencing factors as well as the high cost of human and material resources, this paper establishes an irrigation scheduling analysis method through combination of field observation and numerical simulation. The method was applied to analyze the water consumption characteristics and irrigation scheduling of pepper under the condition of border irrigation in the Shule River Basin. Field observations included soil volumetric moisture content, crop plant height, meteorological data, and soil physical parameters. The Hydrus-1D model was adopted in the method to simulate the water movement process during crop growth period. The calibration and verification of the model were conducted by using data of measured soil volumetric moisture content in the first and second half of pepper growth period, respectively. RMSE (root mean square error) and RMSD (root mean square deviation) were used to quantitatively evaluate the performance of the model. RMSE reflected the average degree of absolute error between the simulated value and the measured value. RMSD was the standardization of RMSE, and reflected the degree of deviation between the simulated value and the measured value. The calibrated and validated model was used to analyze the water consumption law of the crop growth process, and numerical experiments of the irrigation scheduling scenario were conducted to find the better irrigation scheduling with minimum water stress and deep percolation. The amount of water stress was defined as the cumulative amount of soil water content less than 60% of field capacity in the maximum root layer. The results of the method application showed that the total water consumption of pepper during the whole growth period was 456.76 mm under current irrigation scheduling. The ranking of average daily water consumption intensity was swelling stage > fruit setting stage > flowering stage > maturity stage > seedling stage. The results also showed that there was serious deep percolation loss, and water stress occurred in several growth periods, for the amount of deep percolation in the current scheduling during the whole growth period was 171.56 mm and that of water stress was 39.46 mm. In order to obtain the better irrigation scheduling, 96 new scenarios for irrigation scheduling were developed, which included 6 irrigation amounts for each application and 16 irrigation time intervals. With the increase of TIA (total irrigation amount), WC (water consumption) showed an increasing trend, and then became steady, and the range of TIA for WC peaks was 950-1 120 mm. WS (water stress) showed a trend of rapidly decreasing with the increase of TIA, and became extremely small after TIA exceeded 750 mm. With the increase of TIA, DP (deep percolation) showed a trend of slowly increasing first and then rapidly increasing linearly. According to the principle of minimum amount of deep percolation and water stress, taking into account the operating intensity and acceptability of the farmers, this paper proposed that the border irrigation scheduling of pepper in Shule River Basin should be: 525 mm for the total irrigation amount, 9 times irrigation per year, 30-day interval between 2 irrigations in the seedling period, 15-day interval in other growth periods, and 45-80 mm for the irrigation amounts for each application. In practice, it can be adjusted according to specific climatic conditions and soil moisture monitoring. [ABSTRACT FROM AUTHOR]

A hybrid refrigeration system of refrigerator car was designed in this paper. Photovoltaic energy storage system was the auxiliary power source of the refrigeration system and it drove the refrigerator during refrigerator car parking for a long time midway or at night. Engine drove refrigerator when refrigerator car was driving. The experimental analysis of hybrid refrigeration system of refrigerator car found that power generation of solar panels could only keep electric compressor working for 4.13 hours in one day. The power generation was not enough to support refrigeration system working for all night and this would affect the quality of cargo in the refrigerated carriage. In order to solve this problem, on the one hand, the energy consumption of refrigeration system needed to be reduced. On the other hand, the power generation capacity should be increased. Firstly, mathematical model of the hybrid refrigeration system of refrigerator car was established. Then, experiments about photovoltaic energy storage system and refrigeration system have been down. Correctness of the model was verified by comparing experimental data and simulation data. On this basis, the refrigeration efficiency and economic coefficient of photovoltaic power generation were put forward as the system evaluation indexes in this paper. The refrigeration efficiency was the ratio of energy consumption to cooling capacity and represented the energy consumption of the refrigeration system. If the refrigeration efficiency is lower, the energy saving of the refrigeration system is more. The economic coefficient of photovoltaic power generation is the ratio of power generation of solar panels to the power capacity of batteries and it represents the power generation capacity of per-unit cost of photovoltaic energy storage system. If the economic coefficient of photovoltaic power generation is greater, the power generation capacity per unit cost of photovoltaic power generation system is more. The two evaluation indexes were unified as the objective function. Nine constraints were enumerated. Based on chaotic ant colony algorithm, the hybrid refrigeration system of refrigerator car was optimized. The results after optimization showed that the energy consumption of the refrigeration system was reduced by 238.63 W, the cooling capacity was increased by 103.11 W and the refrigeration efficiency was reduced from 0.542 to 0.402. The optimized refrigeration system was more energy-saving. The volume of optimized refrigeration system was smaller, which made refrigeration system easier to install on the refrigerator car. Also, the power capacity of batteries was decreased by 2.67 kW·h, the whole day power generation capacity of solar panels was increased from 4.45 to 5.82 kW·h and the economic coefficient of photovoltaic power generation was increased from 0.464 to 0.840. In summary, the optimized hybrid refrigeration system of refrigerator car was more energy-efficient and economical. The optimization method and encouraging results in this paper will provide a fundamental reference for optimization design of the research on solar refrigeration system. [ABSTRACT FROM AUTHOR]

Automatic poppet valve is a key component of reciprocating pump, which directly influences its performance and lifespan by controlling flow direction of fluid. Many researchers focus mainly on constant stiffness coefficient springs, due to its widespread application in the automatic poppet valve. Previous research already proves that spring plays an important role in the dynamic properties of poppet valve. The main function of spring is to balance inertia force. Studies also suggest that impact velocity and lag height gradually decreases with the increases of stiffness coefficient and preload. However, the increases of stiffness and preload makes head loss rise. Therefore, only by adjusting different combinations of spring stiffness and preload, it is difficult to reduce impact velocity and lag height while reducing head loss. This contradiction restricts the further improvement of reciprocating pump performance. In addition, the determination of the preload and stiffness of spring is often based on empirical formulas in the design process about constant stiffness coefficient spring. To solve these problems, application of variable stiffness coefficient spring on the pump valve was proposed in this paper. In the meantime, a new optimization design method for it was established. The main research contents of this paper included: (i) A mathematical model on the motion properties of valve disc was established under the condition which spring stiffness coefficient was variable. In this model, dynamics differential equation of valve disc motion, continuous flow equation of fluid between valve gaps and initial condition were all considered about. Based on above mathematical model, a computer simulation program was compiled to solve this simulation model by using of Runge-Kutta method. (ii) In order to verify accuracy of simulation model, two contrast tests were carried out. Firstly, lift of valve disc was compared between simulation results and measured results when stroke frequency was 74 min-1. In the process of measurement, the lift of valve disc was measured by lift sensor and pressure in the liquid cylinder was measured by semiconductor pressure transducers. The contrast result showed that the error was less than ±8％. Secondly, by changing parameter of stroke frequency, maximum lift was compared under different stroke frequencies, the error was less than ±10％. In summary, the above comparison showed that simulation model met the requirement of precision. (iii) According to above simulation model, we selected many different combinations of stiffness and preload for the constant stiffness coefficient spring for simulation comparison. After calculation, there was a mutual contradiction between impact velocity, lag height and head loss. In other words, impact velocity and lag height would increase with head loss reduced. Subsequently, in response to above deficiencies, three common types of spring: stiffness decreasing type, stiffness increasing type and stiffness constant type were chosen in the simulation. By comparing with curves of lift, velocity and head loss, it was demonstrated that stiffness decreasing type can improve the suction performance of reciprocating pump, while impact velocity and lag height were not significantly increased. (iv) Based on the numerical simulation model of valve disc motion properties, optimization simulation model of variable stiffness spring parameters was established. In this optimization model, the objective function was that maximum head loss was minimum. The constraint condition was that impact velocity satisfied the theory of no impact. Genetic algorithm and pattern search were used to solve this optimization model. In the end, compared with the constant stiffness coefficient spring, the maximum head loss for variable stiffness spring was reduced by 20.85%. In conclusion, variable stiffness coefficient spring can be used for improving suction performance of reciprocating pump and alleviating the occurrence of cavitation. Besides, this optimization method has a certain guiding significance for guiding design process of spring parameters on the pump valve. [ABSTRACT FROM AUTHOR]

Sowing opener is one of the key parts of seeders, and its working performance affects the seeding quality. Domestic and foreign scholars have done a great deal of research on sowing openers in terms of traction resistance, soil disturbance, soil return performance and blocking performance. But there are few reports on the research of sowing opener for the integrative structure of ditching, earthing and suppressing. In this paper, an integrated sowing opener, which can be used to ditch, earth and suppress, was designed. It can solve the problems such as large disturbance of soil, insufficient compactness of seed bed soil, and poor uniformity of sowing depth. The combination of its sliding knife, retaining plate and repressing wheel can realize the seeding ditch, the seed falling to the bottom of the ditch, the wet soil returning to ditch, the suppressing wheel suppressing the seeding ditch, and the seed being in close contact with the soil. In this paper, the cutting edge curve is analyzed according to the slip cutting principle. It sets the cutting edge curve equation as parabola equation to deduce the conditions which can satisfy the needs of the slide cutting. That is, the slip angle is larger than the friction angle. The final result shows the range of the slider slip angle is 25°-65°. Based on the analysis of the principle of soil reflux after the operation of the trench opener, it can be seen that the change of the obliquity angle of the retaining plate affects the soil disturbance and the soil reflux, and the range of the inclination of retaining soil plate is 0-12.4°. According to the agronomic requirements, the range of soil compactness required for seed growth is 30-50 kPa, and the spring deformation amount is calculated to be 9-15 mm. Finally, the influencing factors can be determined. They are the slip angle, the slope of the retaining plate and the deformation of the spring. The slider slip angle, inclination of retaining soil plate and deformation variables of spring were selected as test factors. Soil compaction and soil disturbance were selected as experimental indices. The optimal parameter combination of the integrated seeding opener obtained from the soil bin text of optimizing the structural parameters was as follows: The slider slip angle was 44.6°, the inclination of retaining soil plate was 3.2° and the deformation variable of spring was 11.8 mm. In order to verify the operation performance of the integrated seeding opener better, field contrast tests were carried out with a double-disc opener and a sharp angle opener under the optimal parameters. The variation coefficient of sowing depth, soil compactness, soil disturbance and backing soil quantity were selected as test indices. The experimental results showed that variation coefficient of sowing depth of the integrated opener was 6.03%, which was 32.4% lower than that of the double-disc opener and 25.2% lower than the sharp angle opener. When the integrated opener was operated, the seeds fell into the ditch prior to the soil, which improved the seeds depth uniformity. The soil compactness was 38.6% higher than that of the double-disc opener and 62.9% higher than that of the sharp angle opener after the working of integrated opener. The suppression part of the integrated opener suppressed the ditches, after the soil-covering ditches were suppressed again by suppressing wheels of the seeder, which increased the soil compaction of the seed bed. The amount of soil disturbance generated by the integrated opener was 16.3% lower than that of the double-disc opener and 36.5% lower than that of the sharp angle opener. But its backing soil quantity was 29.9% higher than that of double-disc opener and 61.5% higher than that of sharp angle opener. Therefore, the integrated opener has little disturbance to the soil. In general, the integrated opener can improve the seedbed environment, enhance soil compaction and improve the uniformity of seeding depth. Besides, this type opener provides an integrated reference for the design of sowing openers. [ABSTRACT FROM AUTHOR]

The spatial layout optimization of rural settlements is the main content of new rural construction, and also one of the key contents of the overall land use planning. The rational spatial layout optimization of rural settlements can not only promote the intensive use of land resources and improve rural production and living environment, but also accelerate the transfer of rural labor force and further narrow the gap between urban and rural development. In order to determine the type of spatial layout optimization of rural settlements scientifically and guide the optimization of spatial distribution of rural settlements and the practice of new rural construction effectively, this paper put forward a spatial distribution optimization method of rural residential areas based on town planning regulation, which was applied to Kekeyiligeng Town in Wuchuan County, Inner Mongolia Autonomous Region. Under the regulation of land use planning at town level, the following steps were in process: First of all, the rural residential areas were divided into 2 different evolution directions based on the location within or outside the boundaries of urban construction land expansion: urbanization and non-urbanization. Specifically, the rural residential areas located within the boundaries of urban construction land extension were identified as urbanization type; conversely the rural residential areas outside the extended boundary range were defined as non-urbanization type. Secondly, the spatial layout optimization type of the urbanization type residential areas was determined as the community-based management mode due to that the rural residential areas as urbanization type were likely to be included in urban construction in their future development. Thirdly, for non-urbanization rural settlements, the evaluation index system for the comprehensive influence of rural residential patches was constructed from 3 aspects: the coordination of town planning, the convenience of production and living, and the activeness of residential areas. Based on comprehensive evaluation scores, the spatial layout optimization types of non-urbanization type were accordingly divided into 3 categories: comprehensive development, in-situ renovation, and combined migration. Finally, the rural settlements optimal layout scheme with 4 optimization types was formulated. The results showed that there were 6 rural residential areas identified as community-based management areas in the study area, with an area of 15.29 hm2, accounting for 2.92% of the total area of the town; 46 comprehensive development areas, with an area of 178.28 hm2, accounting for 35.04% of the non-urbanized rual residential area; 53 in-situ renovation areas, with an area of 189.20 hm2, accounting for 37.20%; 40 combined migration areas, with an area of 141.22 hm2, accounting for 27.76%; the paper also put forward a more specific optimization plan for the 4 optimization types of rural residential spatial layout. Under the framework of town planning regulation, and given full consideration to the space-time arrangement of the rural settlements layout optimization in the town planning period, the optimal layout scheme obtained by the method constructed in this paper is more accordant with practical circumstances in China, and the spatial distribution optimization method of rural residential areas based on town planning regulation can provide a new idea for spatial optimization and renovation of rural residential areas and also provide reference for related research. [ABSTRACT FROM AUTHOR]

With the further reform and development of higher education, the type and quantity of teaching research projects have also increased sharply. Based on the theory of PDCA recycle, this paper sorts out the current procedure of management. The problems are that reasonable layout lacks in the planning phase, the application and reviewing are complicated in the implementation phase, effective supervision also lacks in the execution phase and the practice promotion of teaching achievements is poor. In this paper, the theory and method of portfolio management are used to teaching research project management. It optimizes and innovates the current procedure and works out the index system of score mode on the basis of portfolio management method. According to the life cycle theory, the project manage penetrates the whole project implementation. It forms scientific management system. This paper helps improve the quality of education, form higher quality teaching achievements, and support teaching service. [ABSTRACT FROM AUTHOR]

Diving tubular pump is a kind of low-head large-flow horizontal pump. This type is postpositive bulb pump and the motor is coaxial with pump, which is suitable for irrigation or storm drainage pumping station. For the advantages of excellent hydraulic performance, compact structure, good noise resistance and low operating cost, diving tubular pump is widely applied in low head pumping station. The internal structure of diving tubular pumping system is more complex than other pumping systems for the combination of motor and rotor. Bulb, support slices, cable hole, inlet passage and outlet passage constitute the flow passage components of diving tubular pumping system, which have influence on the internal flow pattern and hydraulic loss of diving tubular pumping system. For low head condition, small increase of hydraulic loss will result in large efficiency loss of pumping system. So the analysis on hydraulic performance of flow passage components of diving tubular pumping system needs to be carried out. In this paper, to acquire hydraulic performance of flow passage components, the inner flow field of diving tubular pumping system is calculated by CFD (computational fluid dynamics). The influence on hydraulic performance of pumping system with different flow passage components is analyzed and the experiment is performed to verify the result of numerical calculation. The head and efficiency difference between model test and CFD simulation are less than 1% in the best efficiency point condition, and the high efficiency range predicted by CFD coincides with the results of the experiment. In order to acquire the influence on hydraulic performance for different numbers of support slices, 3 kinds of slices' numbers are simulated to show that the number of support slices affects the flow pattern between guide vane and support slice. The hydraulic loss of bulb part increases with the number of support slices. The hydraulic loss of pumping system is relatively lower while the support slices' number is equal to guide vane's, which is 5 in this pumping system. Also the shape of bulb tail of pumping system has influence on the flow pattern in outlet passage. Three kinds of bulb tail shapes are calculated, including cone, semi-ellipsoid and semi-sphere. Cone is bad shape for bulb tail, due to the bad flow pattern caused by blunt tail. Semi-sphere is better than cone for less hydraulic loss and better flow expansion in outlet passage. Compared to cone and semi-sphere, semi-ellipsoid is the best shape for bulb tail, which can prevent bad flow pattern like backflow and flow separation. Cable hole is a small pipe which locates at bulb, and its influence on flow pattern and hydraulic loss is ignored by manufactures for its small volume. This paper compares 2 different section shapes of cable hole, specific circle and streamline shape. The result shows that cable hole causes 16% hydraulic loss of bulb, and streamline shape acquires better pressure distribution on cable hole and slightly enhances the flow pattern behind cable hole. Besides, the combination of cable hole and support slice can improve the flow pattern in bulb part and improve efficiency of pumping system. The transition shape of inlet passage between 2 gate slots is also a key factor on hydraulic performance of diving tubular pumping system. Two transition shapes are calculated, including converging square pipe and converging square-circle pipe. Compared with converging square-circle pipe, converging square pipe decreases hydraulic loss of pumping system by 5% and acquires better flow pattern around gate slots. In addition, the other advantage of converging square pipe is the convenience for construction. In conclusion, the efficiency of optimized diving tubular pumping system increases by 2.5%, which reaches 78%. In best efficiency point, the uncertainty of hydraulic performance between simulation and test result less than 1%. [ABSTRACT FROM AUTHOR]

Automatic canal control plays an increasingly important role in water delivery systems, for it is effective in distributing the water resource rationally and reducing the discharge of wastewater. For the control of an open-canal system, the first issue is how to define the control performance indicator, and then the controller could be designed by pursuing the optimized value of performance indicators. The characteristics of canal systems result in the diversity and complexity of performance indicators, marked by big lag, strong nonlinearity, high coupling and multi-input multi-output (MIMO) topology. Therefore, the objective of this study was to improve the existing performance indicators and propose a general indicator reasonably and overall. We tried to demonstrate the feasibility of them by applying in 2 actual canal systems. In this paper, traditional performance indicators of canal control systems were concluded and analyzed, and some additional indicators were replenished and some of them are nondimensionalized by using the design discharge or constant depth of the control point or other inherent parameters. A set of indicators which can evaluate different canal systems were proposed by weakening the influence of canals' dimension parameters. This set was applied to 2 canal systems with different scales: The large-size canal system is 24 km long × 15 m wide × 6 m deep and the small-size canal system is 18 km long × 5-7 m wide × 2.5 m deep, and the larger is around 20 times the size of the smaller. A simulation model of canal systems' control based on MATLAB was constructed, which consisted of 7 modules: physical model establish of canal systems, steady flow state profile calculation, feedforward control module, feedback control module, gate discharge calculation, gate opening transformation and unsteady flow calculation. Among the models, energy equations and de Saint-Venant system of equations were used to compute the constant flow and unsteady flow, and the canal control system was designed which regarded flow rate as the feedforward and the water level as the feedback. Relying on the imulation model of canal systems' control, we optimized the controller parameter aimed at different nondimensional performance indicators, and conducted the comparison between each other. The simulation proved that the optimal values of indicators had high consistency in the order of magnitude with little concern to the canal scale. For example, the optimal NIAQ (nondimensional integrated absolute discharge change) of both canal systems was 10-5. So this series of indicators could be used to compare the performance of different canal systems. However, due to the different optimization effect of single indicator, pursuing the extreme of any single indicator might result in an unbalanced system. Through the analysis of genetic relationship and representativeness among the series of dimensionless performance indicators, a general indicator (GI) was given based on the water level deviation, flow rate changes and transition time with weight. And as far as we're concerned, the control performance was fit for our requirement when the value of GI was no more than 10-3 in magnitude. The simulation results showed that this aimed GI could stabilize the system and balance all dynamic performances of canal systems well compared with a signal indicator. What was more, we studied the flow and water level procedure lines the canal systems showed under different controller parameters by controlling variable. And we discussed the relationship between proportional-integral-derivative (PID) controller parameters and performance indicators. There existed an insensitive range in which the proportional gain could control the flow rate smoothly in pure proportional (P) controller (proportional gain was smaller than 4 in No.1 canal system, and smaller than 15 in No. 2 canal system), and the integral time had a similar effect on water level in proportional-integral (PI) controller. Thus the optimizing method of finding a robust controller was proposed preliminarily: searching the intersection of controller parameters which worked well under different conditions. The series of non-dimensional indicators and GI proposed by this paper can be used to evaluate different canal control systems and different controllers, which can be used as benchmark while designing a new canal control system. This work suggests quite promising solution for the operation of a large number of water delivery systems and irrigation district canal networks in China. [ABSTRACT FROM AUTHOR]

Unmanned aerial vehicles are widely used in agriculture because of the advantages of flexible landing, no contact with plots, and wide adaptability of terrain. Currently, the unmanned aerial vehicle sowing operation is mainly based on the centrifugal sowing device, which mainly relies on the disc to sowing, forming the circular-shape falling area, causing the unstable uniformity of sowing, and it is difficult to control in the direction of the sowing width. In order to meet the needs of unmanned aerial vehicle low-altitude and high-speed sowing operations, and to ensure the uniformity of the sowing, a pneumatic unmanned aerial vehicle sowing device was designed in this paper, making use of the air-flow to blow the seeds out in different directions. The basic working principle was that the seed particles discharged from the metering device were mixed with the high-speed air flow in the flow-spitting box, forming a gas-solid two-phase flow, and then separated into a few streams of seed particles along the diversion channels. The high-spread streams of seed particles, released from the outlet of the diversion channels, cause the formation of a larger width, achieving satisfying sowing presentation. Meanwhile, the key components of the sowing device were simulated and tested. In this paper, the rotor wind field of the multi-rotor unmanned aerial vehicle was simulated and analyzed. The wind field distribution was summarized from two aspects of the vertical plane and the horizontal plane of different heights, and the movement and reasons of the particles in the rotor wind field were analyzed. Three main aspects (the relationship between the outlet size and the wind speed of the air-flow outlets, and the influence of the cone angles of the diversion channel on the airflow, and air pressure distribution in the diversion channel) were studied. The reasons for doing these tests were that the wind speed at the air-flow outlets was the key factor to determine whether the seed can be blown out or not. The design of the diversion channel affected the trajectory of the internal seed particles flow, and the most important thing was the effect on the velocity of the seed when leaving the diversion channel in the size and direction. The effect of the cone angle of the diversion channel on the sowing width and the sowing uniformity was tested. The test results showed that there was a strong negative correlation between the outlet size of the flow-spitting box and the outlet wind speed, and thus, the air outlet size can be determined according to the required wind speed. There was a strong linear correlation between the cone angle and the sowing width of the diversion channel. The correlation coefficient (R2 = 0.999) can be used to determine the appropriate cone angle according to the requirement of sowing width. Considering the distribution of pressure and flow velocity in the diversion channel and the influence on the width and uniformity, 130° was preferred as the cone angle of the diversion channel. Finally, the effects of sowing height on sowing width and sowing uniformity were studied. The correlation analysis method was used to analyze whether the working height in a certain range had an effect on the sowing width. By analyzing the uniformity variation coefficient in the sample areas the effect of working height on sowing uniformity was determined. The results showed that, in the range of 1-2.8 m, the correlation coefficient of height and width was 0.359, greater than 0.05, and the variation coefficient of sowing uniformity was above 15%, and the significance of height and coefficient of variation was 0.197, greater than 0.05, both of which mean that the height of unmanned helicopter had no significant effect on sowing width and sowing uniformity in the range of 1-2.8 m. Therefore, in this range, it is not necessary to consider the effect of the working height fluctuation on the sowing width and uniformity when sowing by this device. In the actual operation, taking into account the sowing width and uniformity coefficient of variation and energy consumption and other factors, the optimal height of 2 m was preferred on the unmanned aerial vehicle. This study provides the basic reference for further optimization of the prototy [ABSTRACT FROM AUTHOR]

Due to the short technical research period in the early stage, many single or special designs issues for Sanhekou Hydro-Junction have limited the process of constructing, such as the insufficient depth, unreality and environmental barriers. In the bidding and constructing stage, the proprietor unit standard from the overall situation and optimized the whole design in time. The optimization indicates that they have shortened the construction duration for 13 months and saved the investor for more than 70 millions Yuan, meanwhile it have improved the construction management efficiency dramatically. This paper analyzed and summarized the construction organization and design optimization results of Sanhekou water Conservancy project from the aspects of concrete mixing system, traffic scheme, slag field, raw material dam foundation excavation, etc. which provided useful reference for similar- engineering constructions. [ABSTRACT FROM AUTHOR]

Sweet potato is an important food crop and energy crop. In order to solve the problems of larger loss rate and high damage rate of 4UZL-1 sweet potato combine harvester during the operation process, a potato connection and conveying mechanism was designed based on the analysis of the structure of 4UZL-1 sweet potato combine harvester and characteristics of domestic sweet potato planting models in this paper. The potato connection and conveying mechanism was mainly composed of a depth limiting mechanism, a digging conveying mechanism, an arc grid conveying mechanism and a scraper chain conveying mechanism. The working parameters were obtained through the kinematic and mechanical analysis of the working process of the mechanism. Aiming at the main evaluation indexes of potato damage rate and loss rate during the transfer and transportation, the Box-Benhnken test was presented on the basis of single-factor test. The angle of the digging conveyor, the conveyor angle of the scraper chain, the conveyor speed of the digging and the conveyor speed of the scraper chain were selected as testing factors. The multiple regression model of evaluation index to each factor was established, and the influence of each factor on operation quality was analyzed, and the optimal structure and operation parameters were obtained. The results showed that the order of the significance influence of factors on potato loss rate from large to small was that the conveyor angle of the scraper chain, the conveyor speed of the digging conveyor, the conveyor speed of the scraper chain and the angle of the digging conveyor. The order of the factors influencing on potato damage rate from large to small was the conveyor speed of the digging, the angle of the digging conveyor, the conveyor speed of the scraper chain and the conveyor angle of the scraper chain. When the forward speed of the machine was 1 m/s, the angle of the digging conveyor was 20°, the conveyor angle of the scraper chain was 68°, the conveyor speed of the digging was 1.2 m/s, and the conveyor speed of the scraper chain was 0.67 m/s, respectively, the potato loss rate was 1.12%, and the potato damage rate was 0.94%. Compared with the predicted values, the relative errors were 3.4% and 1.1%, respectively, the results satisfied the performance requirements of the 4UZL-1 sweet potato combine harvester. The study is benefit for the structure improvement and operation parameters optimization of the sweet potato combine harvester. [ABSTRACT FROM AUTHOR]

China is rich in crop straw resources, but straw burning is serious and resource utilization is not high. To solved the ecological pollution and resource waste caused by straw burning, and let straw carbonization equipment market promotion. The orthogonal experiment of carbonization process was designed according to the literature and the results of preliminary experiment. The straw biochar produced by process test was analyzed. The thermal characteristic parameters and combustion characteristic parameters were calculated. Straw biochar yield, fuel ratio, hydrocarbon atomic ratio, alkalinity index, high calorific value and dimensionless comprehensive combustion index Z were used as quality evaluation indexes for high quality straw biochar. Grey correlation analysis method and comprehensive quality score method were used to analyze the evaluation indexes and influencing factors, and the response surface method designed by CCD experiment was used to optimize the production process of straw biochar directional regulation. The experiment provides a theoretical basis for improving the energy utilization rate of straw and provides a large number of data support for the popularization and application of continuous straw carbonization equipment. The results showed that temperature was the primary factor affecting the quality of straw biochar. The five evaluation indexes of straw biochar quality except the yield of straw biochar were ranked as follows: Z > H/C >FR >AI >HHV, the quality of straw biochar produced by the equipment is stable and close to the burning quality of bituminous coal. In the orthogonal experiment, the experiment in group 16 and group 12 obtained a higher comprehensive score, and the optimal process parameter combination was A3B4C1. CCD test results after response surface optimization, in the balance of the two response values to meet the maximum, the predicted optimal process parameters are: cut after the corn straw, after 600 ℃ thermal carbonization for 50 min, the production of straw biochar output is 53.05%, its combustion index Z is 0.726 6. The empirical test showed that the difference between the experimental value and the predicted value was less than 0.2%, the fitting model and the response surface optimization method were accurate and feasible, and the combustion quality of straw biochar produced by the optimal carbonization process was greatly improved. The C content and H/C of straw biochar produced under the best technological conditions are increased by nearly 2 times, which is closed to the combustion quality of bituminous coal and anthracite, and far better than the barbecue biochar purchased in the market. Through the carbonization process in this study, the utilization quality of straw biochar can be controlled directionally, forming a reproducible and generalized quasi-directional regulation method of high quality fuelized straw biochar. The analysis methods greatly reduce the experiment times, choose the appropriate fuel straw biochar quality evaluation index, and on the premise of saving the cost of raw materials and energy, quick understanding of high quality energy straw biochar production process parameters, facilitate continuous piecewise uniform crop straw carbonization market-oriented all-round production system of rapid popularization and application.In addition, the experimental design and data analysis method in this paper can also provide data support for the production of straw carbonization process using straw as raw material for adsorption and fertilizer carbon. [ABSTRACT FROM AUTHOR]

In recent years, the pneumatic centralized fertilizing and seeding methods were developing rapidly. The pneumatic centralized fertilizing system was mainly used for layered fertilizing operation. The fertilizing pipes of the fertilizer discharging system were connected with the fertilizer outlet of the layered fertilizing shovel. Under the actions of air flow, the fertilizer was transported to the outlet of the fertilizing shovel quickly and remotely, so as to realize the layered application of the fertilizer in the soil. In this paper, in view of the problems such as the fertilizer falling into the inlet was not smooth and the airflow velocity at the outlet was too high, which leading to fertilizer bounce and dust when the fertilizer discharging system and layered deep fertilizing shovel were combined, the relationship between the structure of each part of the fertilizer discharging system and the working parameters was studied through the test-bench of the pneumatic centralized fertilizer discharging system, and the structure of the fertilizing system was optimized. An air-fertilizer separation device was designed, which was installed between the distributor outlet and the fertilizer discharging pipe of the layered deep fertilization shovel, part of the airflow from the fertilizing system was discharged by the air-fertilizer separation device in advance to reduce the airflow velocity at the fertilizer outlet of fertilizing system. The structure and basic working parameters of each component of fertilizing system were determined through theoretical analysis and parameter calculation. In specific, the airflow velocity of the fertilizing system inlet should be greater than 25 m/s, the diameter of the air-fertilizer conveying pipe, fertilizer inlet and fertilizer outlet was 76, 55 and 20 mm, respectively. The main factors affecting the airflow velocity at fertilizer outlet and inlet of fertilizing system were also determined through analysis. Taking the exhaust outlet area of the air-fertilizer separation device (A), the airflow velocity of the fertilizing system inlet (B) and the fertilizing rate (C) as the test factors, the quadratic regression rotary orthogonal platform experiment was conducted. According to the test results, the mathematical regression model between the test indexes and the influencing factors was established. The results showed that the exhaust outlet area of air-fertilizer separation device, airflow velocity of the fertilizing system inlet and fertilizing rate had a significant effect on airflow velocity at fertilizer outlet of fertilizing system, and exhaust outlet area of air-fertilizer separation device had a significant effect on the airflow velocity at inlet of fertilizing system. The optimized parameters were conducted by fitting and optimizing the test results. It was obtained that airflow velocity at fertilizer outlet, fertilizer inlet of fertilizing system was 5.91 and 3.94 m/s, respectively, the exhaust outlet area of the air-fertilizer separation device, airflow velocity of the fertilizing system inlet and fertilizing rate were 798.0 mm², 28.10 m/s and 0.28 kg/s, respectively. The verification test results showed that the airflow velocity at fertilizer outlet and fertilizer inlet of the system was 6.02 and 4.11 m/s, the fertilizer at the inlet of the fertilizer discharging system falled smoothly and stably. [ABSTRACT FROM AUTHOR]

To solve the problems of low removal rate and incomplete separation for the current longitudinal-axial-flow combined harvester in the case of harvesting rice and wheat, a segmented longitudinal-axial-flow threshing device was designed in this paper. The threshing device mainly comprised a tapered threshing roller, a concave sieve with adjustable threshing strength, a 360° separation device and an electric control system for operating parameters. Through the single factor tests, the optimal switching states of the concave sieve with adjustable threshing strength for rice and wheat threshing was obtained respectively. In order to find out the influence rule of the working parameters of the device on the threshing effects and the optimal parameter combination, the multi-objective optimization tests were carried out. The rotational speed of roller, the angle of deflector, the threshing gap of concave sieve, the separation gap of concave sieve and the feeding rate were selected as the influence factors and the crushing rate, impurity rate and loss rate were selected as the test indexes. The test results showed that the significant sequence of influence of threshing parameters on the crushing rate was the rotational speed of roller, the threshing gap of concave sieve, the angle of deflector, the feeding rate, the separation gap of concave sieve. The significant sequence of influence of threshing parameters on impurity rate was the rotational speed of roller, the angle of deflector, the threshing gap of concave sieve, the feeding rate, the separation gap of concave sieve. The significant sequence of influence of threshing parameters on loss rate was the rotational speed of roller, the angle of deflector, the threshing gap of concave sieve, the feeding rate, the separation gap of concave sieve. Through multi-objective parameter optimization analysis, the optimal working parameters combination for wheat threshing were determined that the rotational speed of roller was 905 r/min, the angle of deflector was 69°, the threshing gap of concave sieve was 18 mm, the separation gap of concave sieve was 19 mm and the feeding rate was 4 kg/s. The field verification tests were carried out using the optimal working parameters combination. The results indicated that the crushing rate was reduced from 1.46% to 1.00%, the impurity rate was reduced from 1.85% to 1.43% and the loss rate was reduced from 1.72% to 1.20% compared with the conventional longitudinal-axial-flow threshing device. All the relative errors between the measured values and the optimized values were less than 5%, the working indicators met the requirements of relevant national standards. The device effectively solved the problems of high crushing rate, unclean threshing and incomplete separation, the research results can provide reference for the structural improvement and operation parameters optimization of the threshing device of longitudinal-axial-flow combined harvester. [ABSTRACT FROM AUTHOR]

In order to solve the problem of poor growth quality of pot seedling caused by large soil disturbance and low soil porosity of the hole wall during the hole forming process of soil opener for rapeseed transplanting machine, simulation analysis of the hole forming process of two different types of soil openers was carried out by using the discrete element method software EDEM according to the physical size parameters of rapeseed pot seedlings and the agronomic requirements of transplanting pot seedlings of rapeseed in this paper. The discrete element method was used to establish and modify a soil model consistent with the physical and mechanical characteristics of the soil in the test bin. In combination with the movement trajectories of the two different types of soil openers, hole forming method (soil picking type and soil extruding type) of soil openers, bottom size of soil opener and soil opening depth were chosen as the test factors. The soil return coefficient in the hole section and the soil porosity of the hole wall were chosen to evaluate the effects of various test factors on hole morphology and soil disturbance. The discrete element method simulation results showed that soil picking type soil opener was a relatively superior method for hole forming. The soil return coefficient in the hole section and soil porosity of the hole wall of soil picking type soil opener were better than that of the soil extruding type soil opener. The section shape of the hole formed by the picking type soil opener with square structure at the bottom was a rectangle. The longitudinal length of the top of the hole was less than the width of the top of hole, and the longitudinal length of the bottom of hole was larger than the width of the bottom of hole. The optimal parameter combination of the soil opener required by agronomic hole size requirement was obtained as follows: the bottom size was 50 mm, the soil opening depth was 40 mm, the length and width of the hole top size formed by soil picking type soil opener was 69 mm and 79 mm respectively, the effective depth was 40 mm, the soil porosity of the hole wall was 48.5%, and the soil return coefficient in the hole section was 0.08. Physical soil bin test was carried out to verify the operating performance the soil opener. The soil in the test bin was treated so that the soil conditions of the simulated soil were consistent with those of the soil in the test bin. The results of soil bin test showed that the average error between the simulation results and the soil bin verifying test results of the longitudinal length of top, width of top, effective depth, soil porosity of the hole wall and the soil return coefficient in the hole section of the hole formed by soil picking type soil opener were 4.8%、3.4%、1.2%、1.5% and 14.2%, respectively, the optimized soil opener could form holes that meet the design requirements. This study provides a reference for the next step of optimization of soil opener. [ABSTRACT FROM AUTHOR]

Thermal storage performance is the key to improve the overall efficiency of solar hot water utilization systems. In order to find the optimal structure of solar water storage tank to adapt to the actual situation of solar energy resources in Urumqi, and to determine the optimal operating conditions in different periods of time, the flow and heat transfer processes in solar water storage tank under 25 different working conditions were numerically analyzed by standard k-ε model in this paper. The results showed that the thermal stratification effect of the solar water storage tank with the flat roof was the worst one, the dimensionless exergy was 0.903, the solar water storage tank with the spherical foof was the best and the dimensionless exergy was 0.881. The solar water storage tank with flat roof had the highest instantaneous heat transfer efficiency and its value was 0.899, while the solar water storage tank with the spherical roof had the lowest value 0.855. At 11:30, 13:00, 15:00, 16:20 and 18:00, the solar water storage tank with spherical roof could obtain the optimal thermal stratification effect when the cold water inlet velocity were 0.42, 0.42, 0.1, 0.18 and 0.26 m/s, respectively. The minimum dimensionless exergy for the five times were 0.879, 0.873, 0.879, 0.881and 0.874, respectively. For the five studied times, however, the solar water storage tank with spherical roof had the maximum instantaneous heat transfer efficiency when the cold water inlet flow velocity was 0.10 m/s. And the maximum instantaneous heat transfer efficiency for the five times were 0.864, 0.852, 0.864, 0.865 and 0.862, respectively. If the solar water storage tank was used for heating, the lower limit of cold water inlet velocity of the tank was 0.26 m/s. When the inlet velocity of cold water was under 0.26 m/s, the parallel operation mode of water tank or combined operation mode of water tank and electric heating boiler should be adopted. This study can provide reference for the operation optimization of solar energy storage system in different climate conditions. [ABSTRACT FROM AUTHOR]

There are a lot of blind application of chemical fertilizers in the planting of bananas, which leading to waste of fertilizers and environmental pollution. According to the distribution pattern of banana root system, a variable fertilizer apparatus was designed in this paper. Based on the image processing of banana root morphology and the statistics of the area area pixels, the distribution pattern of the banana root system in the horizontal direction was analyzed. Based on the characteristics of the root area distribution, the change of fertilization amount along with the root distribution in horizontal was normally distributed, that is, the amount of fertilizer in the main root was the largest. Based on this, a rotary plate variable fertilizer apparatus was designed. By calculating the fertilizer amount distribution discharged on the simulated ground by the simulated fertilizer discharger, it was determined that the distribution law of the fertilizer amount along the forward direction of the machine was also normally, which was the same with the banana root distribution. In order to ensure that the fertilizer discharging amount and the center position of the normal distribution of the root are consistent in space, taking the spatial consistency of the center positions of the two normal distribution as the goal, the operation process planning was carried out for the image acquisition interval time, algorithm time, motor response time, fertilizer falling time, etc., and the accompanying operation control model of the machines was established. The variable control system was used to achieve and ensure that the center positions of the two normal distributions were consistent in space. The center combination simulation test was carried out with the movement speed, the moving period of the rotating plate, the central angle of curved slot and the opening size of curved slot as independent variables, and the length of fertilizer distributing and the fertilizer discharge amount were used as test response values. The result of optimal parameter combination was that the movement speed is 0.25 m/s, moving period of the rotating plate is 10.00 s, the central angle of curved slot is 90.00°, and the opening size of curved slot is 20.00 mm. The model and test errors, simulation and test errors of the length of fertilizer discharge are 4.98% and 3.30% respectively, the model and test error, simulation and test error of fertilizer discharge amount are 11.15% and 6.68%, respectively. The field test was conducted to examine the field operation effect of the fertilizer discharger, the average qualified rate of fertilizer discharging length was 96%, the average qualified rate of fertilizer discharge amount was 95.33%，the operation performance of fertilizer apparatus was good. [ABSTRACT FROM AUTHOR]

Mechanical precision seed metering device is widely used in precision seeding technology because of its simple structure and uniform seed metering. Seed filling process is the key link of the whole operation process of seed metering device. The precision metering device is mainly divided into internal filling, side filling, external filling, and the combination of side filling and external filling according to the seed filling mode. In the operation process, the internal filling mode mainly completes the seeding operation through the process of type-hole filling and gravity clearing, and the seed motion parameters close to the type-hole directly affect the seeding quality of the machine. The rotary type-hole cotton precision seed metering device is a kind of mechanical precision seed metering device. In order to solve the problem of missing seed in the process of filling, the influence of the motion parameters of rotary type-hole cotton precision seed metering device on the filling performance by establishing the kinematic model of the seed filling process in this paper. Using the discrete element simulation software to analyze the speed change trend of cotton seed falling into the type-hole and the influence of seed wheel vibration frequency on seed group disturbance. Taking the vibration frequency of seed wheel, vibration offset angle of seed wheel and rotating speed of metering device as the test factors, and taking the qualified rate of seed spacing, replaying rate and missing rate as the test indexes, three factors and five levels of positive traffic rotation combined test are carried out to explore the influence of each factor on seed metering performance. Design expert 8.0.6 software is used to analyze the test results and optimize the regression model. Single factor simulation test results show that the instantaneous speed of cotton seed increases with the increase of the rotating speed of the seed wheel, the instantaneous speed of the cotton seed is less than that of the seed wheel when it is filled into the type-hole, the cotton seeds with lower relative speed have better filling effect. When the vibration frequency of the seed wheel is 7 Hz, the average value of the normal force of the seed group is the smallest, which is 0.75 N, at this time, the internal friction of the seed goup is the smallest, the cotton seed is easy to be taken by the type-hole, and the seed filling performance of the seed metering device is improved. The simulation results of quadratic regression general rotation combination show that when the rotating speed of the seed metering device is 12.59 r/min, the vibration offset angle of seed wheel is 8.06° and the vibration frequency of seed wheel is 6.08 Hz, the qualified rate of seed spacing reaches the maximum of 94.5%, and the leak seeding rate is 2.9%, the repaly rate is 3.3%. On this basis, the platform validation test was carried out with Xinluzao No.61 cotton seed as the test object. The test results showed that when the rotating speed of the seed metering device was 12 r/min, the maximum qualified rate of the seed spacing was 94.65%, the error between the rotating speed of the seed metering device and the simulation test is 5.4%, which verifies the accuracy of the simulation results. This study can provide a reference for the structural optimization of the key components of the rotary type-hole cotton precision metering device. [ABSTRACT FROM AUTHOR]

In the implantation process of garlic mechanized seeding, under the strong coupling among garlic seeds, soil and parts touching it, the verticality of adjusted garlic seeds is very easy to reduce again, thus affecting the final garlic output and garlic quality. How to ensure that garlic seeds are planted in an upward vertical direction has become a key technology to be solved. To solve this problem, this paper took the planetary wheel garlic planter designed in the early stage as the research object, introduced its structure and working principle in combination with the whole garlic planter, realized the adjustment of the opening and speed ratio of the inserting duckbill by processing the cams of different planters, and changed the opening phase angle of the inserting duckbill by adjusting the circumferential position of the cams installed in the machine. Based on the establishment of garlic inserting seed model and the analysis of the process, the tip motion equation of the duckbill was established and imported into CAXA software to generate the movement track. Through the analysis of the movement track under different parameters, it is clear that the key factors that affect the verticality of garlic seeds after planting are the linear speed of the inserting duckbill, the opening phase angle and the ratio of the opening angle of spigot duck's beak to the center angle corresponding to the cam convex section (the opening and speed ratio). In order to verify the correctness of the theoretical analysis, a garlic planting test-bed was developed, and the indoor experiment of Cangshan garlic planting was carried out. Through the single factor experiment, it was determined that the value range of the linear speed of the duckbill was 200-500 mm/s, the range of the opening phase angle was 0-20°, and the range of the opening and speed ratio was 1-2. In order to obtain the optimal parameters of these three factors, the Box-Benhnken central composite test method was used to design the linear velocity, opening phase angle and opening velocity ratio of the spilt duck's beak by three factors and three levels quadratic regression test. The sowing test was carried out, and the response surface mathematical model was established by using Design-expert software. The key parameters affecting the verticality were comprehensively optimized. The optimal working parameters are as follows, the linear speed is 200 mm/s, the opening phase angle is 20°, the opening and speed ratio is 2. In order to verify the performance of the inserter using the optimized parameters, field experiments were carried out. The results showed that the average vertical degree of garlic seeds in the optimal parameter operation was 63.2°, which was 21.8% higher than that before. It not only met the requirements of garlic planting vertical degree, but also further improved the integration of agricultural machinery and agronomy, which improved the guarantee for large-scale mechanized vertical sowing of garlic. [ABSTRACT FROM AUTHOR]

In modern agricultural production, the arched shed is more and more widely used in vegetable cultivation and seedling breeding. The arched shed is mainly built by manual. At present, the agricultural demand of arched shed width is about 0.8-1.5 m, and the height of arched shed is about 0.4-1 m. In order to improve the mechanization and automation level and the efficiency in the process of building arched shed, automatic cuttage device of arched shed was designed in this paper. Automatic cuttage device of arched shed was mainly composed of hydraulic transmission system, arm bending, crank slide mechanism, and tent pole cuttage mechanism. The hydraulic transmission system was the power source of the device. According to the technical requirements of building the arched shed and the conditions for the existence of crank, the structural optimization design of the crank slider mechanism was carried out, which was the critical component of automatic cuttage device of arched shed. When the length of the crank was 230 mm, the length of the connecting rod was 220 mm, and the eccentricity was 220 mm, the best force transmission effect and the movement efficiency were achieved. In addition,, the motion analysis of the crank slider mechanism was carried out. The initial angle and the maximum position angle of the crank were determined as 132° and 30°, respectively. The bending arm was designed to bend the shed rod, and at the same time to ensure that the shed rod vertical into the soil. The stress analysis of the rod in the initial state was simulated with different place of application of force, which is the different distance between the end of the bending platen and both ends of the rod. The closer this distance is, the greater the deformation will be. Therefore, the total bending arm length was set to be 44 cm, of which the length of bending platen was 7 cm. The thin and soft skeleton of the arched shed was covered with a flexible plastic film on the outside of the structure, which is more sensitive to the wind load. It is particularly important to ensure the wind resistance of the arch canopy. The wind resistance of small arch shed was analyzed by ANSYS, and it was found that the wind resistance of arched shed was the best when the ratio of frame width to frame length was between 0.60-0.66. The key parameters such as the height of the roof from the top of the shed, the width of arbor and the depth of shed insert soil were measured. The average buried depth was 15.23 cm, and the stability coefficient was 97.86%. The average height and width of the tunnel were 56.19 cm and 93.85 cm respectively, the stability coefficient of them were 99%. Combined with the agricultural demand, the errors were within the allowable range. The correctness of the optimized design, the feasibility of the solution and the stability of the machine operation are further verified. [ABSTRACT FROM AUTHOR]

For solving the optimization operation model of parallel pumping stations, wolf pack algorithm (WPA) has some problems such as poor convergence and robustness. In order to improve these problems, taking a typical parallel pumping station group as an example, aiming at the lowest energy consumption of the main unit of the pumping station system, and considering the constraints of flow rate, blade angle and number of running units, a mathematical model for optimal operation of parallel pumping stations was established in this paper. Simulated annealing algorithm (SA) was introduced into WPA, named as hybrid wolf pack algorithm (HWPA), which was proposed to solve the established optimization model. Minimum value, average value and standard deviation of energy consumption were used to evaluate the performance of the algorithm. Compared with particle swarm optimization (PSO) and WPA, the minimum value of energy consumption based on HWPA was decreased by 15.60 kW and 10.23 kW on average of energy consumption, the average value of energy consumption was decreased by 36.94 kW and 14.30 kW on average respectively, and the standard deviation was decreased by an average of 84.82% and 72.90% respectively. On the basis of the HWPA, four parameters of walking step, running step, minimum and maximum of siege step in the algorithm were analyzed by single factor simulation. At the same time, the min-max standardization method was used to standardize the minimum value, average value and standard deviation of energy consumption. The standardized value was further weighted to get the comprehensive evaluation index(E) of the algorithm evaluation. Then, according to the trend of E, the reasonable range of the above four parameters was determined. According to the results of single factor analysis, the four parameters mentioned above were selected as independent variables, and latin hypercube sampling was used to design simulation. Considering the minimum value, average value and standard deviation of energy consumption, the optimal combination of parameters was determined to be 0.33, 1.53, 0.672 and 4.8×105, and then the improved hybrid wolf swarm algorithm (IHWPA) was proposed. Compared with HWPA, the minimum and average value of energy consumption based on IHWPA were reduced by 4.66 and 13.26 kW on average, and the standard deviation was reduced by an average of 94.02%. IHWPA was used to determine six optimization schemes of typical parallel pump stations under different operation conditions. The results showed that the global convergence and calculation robustness of the algorithm were improved by introducing SA algorithm and optimizing the parameters of WPA. The optimal scheme reduces the energy consumption by 9.80% on average compared with the actual operation scheme, and the energy saving effect was significant. When the total pumping flow rate was small, the optimization effect of the optimization scheme was more significant, conversely, the difference between the two schemes became smaller, but the energy consumption of the optimization scheme was still lower than that of the actual scheme. It can be concluded that IHWPA is suitable for solving optimal models for this kind of pumping stations, which can provide a reasonable and effective operation scheme for pumping station engineering and reduce the operation energy consumption. [ABSTRACT FROM AUTHOR]