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One of the critical barriers for whole-stalk sugarcane mechanical harvesting is the high proportion of impurities especially in the cane tops. In this study, a whole-stalk sugarcane conveying and top breaking system was developed and tested to improve top breaking performance. Effects of feeding roller speed, top breaking roller speed, stagger angle of upper and lower top breaking elements and distance between the upper and lower top breaking element on sugarcane top breaking rate, non-fracture rate and power requirement were explored. Central composite design combined with response surface method was employed to conduct experiments and explore the interaction effects of influence factors on indicators. The optimal structure and operating parameters were determined to be 305 rpm for feeding roller speed, 520 rpm for top breaking roller speed, 14° for the stagger angle and 10 mm for the distance. The predicted values for top breaking rate, non-fracture rate and power requirement were 85%, 83% and 690 W, respectively. Verification experiments demonstrated that the observed values were in agreement with the predicted values. Based on the optimised results, a rigid-flexible coupling model was established for sugarcane conveying and top breaking and the simulation results showed that the model was reliable in predicting the kinetic characteristics of sugarcane in conveying and top breaking processes. The maximum resultant striking force of the top breaking elements on the cane stalk was 807.68 N. Overall, the conveying and top breaking system developed in this study was effective for improving top cleaning performance in whole-stalk sugarcane harvesting.

HighlightsThe cutting mechanism of sugarcane stalks using single-point clamping was analyzed.Physical properties, chemical composition, and maximum cutting force of sugarcane were explored.Strong and complicated correlations between physical properties and chemical composition were established.Stress distributions in sugarcane stalks and the cutting blade were predicted using a finite element model.Abstract. Research on the cutting characteristics of sugarcane stalks is of great significance to improve harvest mechanization. In this study, perpendicular cutting of sugarcane stalks at six different nodes and internodes along the stalk was tested using a single-point clamping method at three cutting speeds (30, 40, and 50 mm min-1). The physical properties and chemical composition were also measured. At the 50 mm min-1 cutting speed, the maximum cutting forces at nodes and internodes upward along the stalk decreased gradually from 810 to 530 N and from 600 to 440 N, respectively. The maximum cutting force was positively correlated with the cutting speed at the same position. Differences in the microstructures of nodes, internodes, and epidermis were revealed by SEM micrographs. The physical properties and chemical composition of the stalks showed significant correlations. Correlation analysis was used to clarify the complicated interrelationships among these independent variables and revealed the interacting mechanism between physical properties and chemical composition. A finite element model was established to simulate the sugarcane cutting process. Results showed that the simulated cutting resistance of the blade was close to that in the experiments. The maximum Von Mises stress of the sugarcane stalk and blade in the cutting process were about 23.34 and 254.17 MPa, respectively. The results of this study provide guidance for designing and optimizing base-cutters of sugarcane harvesters and similar cutting equipment. Keywords: Chemical composition, Correlation analysis, Cutting characteristics, Microstructure, Physical properties, Simulation.

Improving sugarcane chopper harvesters in terms of chopping quality is essential to reduce harvesting loss and costs. In this study, a chopper system used in a sugarcane harvester was developed and utilized to evaluate the effect of rotational speed of chopping drums (X1), overlapping length of upper and lower chopping blades (X2) and bevel angle (X3) on chopping quality and power requirement. Box-Behnken design combining with response surface method was employed to obtain the optimal operating parameters. The significance of independent variables and their interactions were tested by analysis of variance with 95% confidence limit (α = 0.05). The optimal values of the selected variables were obtained by solving the regression models, as well as by analyzing the response surface contour plots. The optimal values of three test variables were computed as X2 of 2 mm and X3 of 21.8°. Based on these conditions, when X1 increased from 200 to 250 rpm, the percentage of undamaged billets decreased from 97.0 to 95.6%, the average maximum chopping power requirements increased from 515 to 625 W, and the standard deviation of chopping length increased from 1.24 to 1.36 mm. Verification experiments indicated that the observed values were in agreement with the predicted values. A high-speed camera system was then applied to capture the stalk trajectory during chopping process. Results suggested that maintaining a stable and low conveying speed of sugarcanes during mechanical harvesting could reduce stalk damage and juice loss, which contributed to high chopping quality.

As a labor-intensive operation, manual harvesting greatly affects cost and therefore profitability in the cabbage industry. A new compact self-propelled cabbage harvester for small, separate fields was designed and field tested. This harvester included a crawler chassis, a picking mechanism, a lifting mechanism, a cutting device, and a leaf separator. Results of preliminary field tests showed that the harvester had good flexibility and maneuverability. Results of field performance tests showed that the harvester could pick cabbages with diameters of 15 to 25 cm, providing a harvesting capacity of 0.21 hm2 h-1 and a harvest loss of 10.2%. Compared with experiments conducted in traditional fields, harvest quality showed an improvement in fields with an experimental cultivation method. The harvest loss was reduced by 5.0%, while the picking rate and accurate cutting rate were improved by 3.0% and 5.4%, respectively. Keywords: Cabbage, Compact, Field test, Mechanical harvester, Self-propelled.

High levels of mechanical damage are a major obstacle for the mechanical harvesting of sugarcane. A chopping system for use in a sugarcane harvester was developed and tested. The three influencing factors studied were the rotational speed of chopping drums (RS), the overlapping length of upper and lower chopping blades (OL) and the bevel angle (BA). The quality of chopping included the percentage of undamaged billets (PUB) and the standard deviation of chopping length (SDCL), and together with the average maximum chopping power consumption (PC) these were regarded as outputs. A Box-Behnken design was employed to conduct the experiments and build regression models. The optimised results indicated that when RS increased from 200 to 250 rpm on the condition that OL and BA were set as 2 mm and 21.8°, respectively, PUB decreased from 97.0% to 95.6%, with PC increasing from 515 to 625 W and SDCL increasing from 1.24 to 1.36 mm. Based on these optimised parameters, a finite element model was established to simulate the chopping process. The chopping resistance of blades, stress distribution of sugarcane and blades in the chopping process were then analysed. Results showed that the maximum Von Mises stress of sugarcane, upper and lower chopping blades in the chopping process were about 16.87, 106.08 and 115.72 MPa, respectively.

This paper aims to investigate the feasibility of using brake pad waste (BPW) in cement emulsified asphalt mixture (CEAM). The effects of BPW filler on early-stage strength, mechanical properties and durability of CEAM were experimentally studied, while mixtures with basic oxygen furnace (BOF), fly ash (FA), hydrated lime (HL) and conventional limestone filler (LF) were prepared and tested as comparison. Results indicate that strength of BPW mixture in early stage and after fully cured are smaller than that for the contrasting mixtures with common by-product fillers. The reason might be that BPW filler has no significant effect on hydration reaction of cement, due to its non-active characteristic. However, the engineering performance of BPW mixture is comparable to that with artificial by-product fillers. Moreover, result of dynamic modulus test implies that the temperature and frequency dependence of CEAM is weaker than the HMA. And there is no obvious difference in viscoelastic characteristics of CEAM mixes using various fillers concerned. The research demonstrates that BPW filler can be used as an alternative material for mineral filler in CEAM.

Cabbage harvesting in China is still done by hand. As the farming labor from rural areas poured into industry, this situation will become a challenge in the near future. A self-propelled cabbage harvester was developed and its field tests were carried out by Zhejiang University to satisfy the ascending demand for cabbage harvesting. To achieve this project, an investigation of cabbage physical properties became the first task providing the reference for machine design. Then the once-over harvester attached to a self-propelled crawler tractor was designed and manufactured, including picking mechanism, lifting mechanism, dual disk saws, leaf separator, and hydraulic system. This harvester picks up the cabbage plants with a pair of picking shovels and delivers them using a pair of transverse belts. In the delivering process, the plant roots are cut by dual rotating disk saws and discarded at the end of tooth-chains. In the rear of harvester, a rotating rubber roller removes the wrapping leaves from the balls. Finally, the cabbage balls are loaded into the bin. After the lab and preliminary field tests, some of the key components were improved. The harvesting tests in experimental and traditional fields were conducted in Zhejiang Province in 2015, and the results demonstrated the harvester had a good capability, feasibility and productivity. When operating at the speed from 0.2 to 0.4 m/s, the harvester presented a good harvesting quality, whose picking rate was more than 90%, delivering rate was almost 100%, accurate cutting rate varied from 57.8% to 75.0%, leaf-separating rate was from 68.0% to 80.0%, and harvesting loss was less than 6.7%. In addition, we found that the ripe uniformity and cabbage variety were also the important factors influenced the harvesting quality. By comparison, the harvesting quality in experimental fields was much better than that in traditional fields. These results provided some critical information required for the improvement of this self-propelled cabbage harvester in China.

Leaves cleaning and top severing, as the key procedures during whole stalk sugar cane harvesting, are influenced by growth height and lodging status of cane stalks. A whole stalk operating system after sugar cane severing was designed and experimented to improve the adaptability of sugar cane harvester. In this system, the rotary rollers of leaf-shredding, leaf-cleaning and top-severing lacerated and peeled leaves by producing centrifugal and frictional force. According to the mechanical properties of cane stalks, the anti-deformation and impact resistance of the tops were significantly lower than other parts, and the anti-float mechanism was designed for severing tops. In this experiment, the speeds of leaf-shredding, leaf-cleaning and top-severing rollers were regarded as experimental factors. Four indices (impurity rate, top-severing rate, abrasion rate and non-fracture rate) were selected as assessment criteria. The working parameters were optimized using quadratic general rotary unitized design to find out the optimum parameter combination. The results indicated that the top-severing rate and abrasion rate were influenced by the speeds of three kinds of rollers significantly. However, the non-fracture rate was influenced by the speeds of top-severing rollers only, though they had no effect on the impurity rate. Optimum working parameters were nonlinearly optimized and determined as 512.9 r/min of leaf-shredding roller speed, 418.8 r/min of leaf-cleaning roller speed and 307.0 r/min of top-severing roller speed. Under the optimized conditions, the verification experiments showed that the experimental results were consistent with the theoretical results.