Effects of Different Vibration Intensities Harvesting on Photosynthesis System Parameters of Lycium barbarum L. Trees with Harvest Machine

The effects of different vibration intensities harvesting on photosynthesis system parameters of Lycium barbarum L. tree with harvest machine were researched. The result showed that the photosynthetic rate, transpiration rate, stomata conductance and intercellular CO2 concentration of L. barbarum tree＇s leaves under different treatment during different periods have no significant difference compared with contrast. It indicates that there is no significant effect on photosynthesis system parameters of L. barbarum tree＇s leaves with harvest machine.

Soil moisture content as a predictor of soil disturbance caused by wheeled forest harvesting machines on soils of the Western Carpathians

Limiting surface soil disturbance caused by forest harvesting machines is an important task and is influenced by the selection of efficient and reliable predictors of such disturbance. Our objective was to determine whether soil moisture content affects soil load bearing capacity and the formation of ruts. Measurements were conducted in six forest stands where various machines operated. We measured the formation of ruts along skid trails in connection with varying soil moisture content. Soil moisture content was determined through the gravimetric sampling method. Our results showed that severe（rut depth16–25 cm） to very severe disturbance（rut depth [26 cm）occurred in forest stands where the instantaneous soil moisture exceeded its plasticity limits defined through Atterberg limits. Atterberg limits of soil plasticity ranged from 26 to 32 % in individual stands. Regression and correlation analysis confirmed a moderately strong relationship（R = 0.52; p ／ 0.05） between soil moisture content and average rut depth. This confirmed that soil moisture is a suitable and effective predictor of soil disturbance.

不同土壤对甘蔗入土切割负载压力影响的研究

针对甘蔗收获机入土切割系统负载压力的预测适应性差、准确性低的问题,通过正交试验探究在不同土壤类型下切割系统的负载压力与入土切割深度、土壤含水率、甘蔗密度及土壤硬度等因素之间的关系并对各影响因素的显著性进行排序;根据试验结果搭建基于BP神经网络的负载切割压力的预测模型并进行验证。试验及验证结果表明:各土壤中入土深度、土壤含水率、甘蔗密度对切割系统负载压力影响显著,红壤的土壤硬度影响显著,而冲积壤的入土深度与土壤含水率交互作用影响较大;预测验证得出黄壤、红壤、冲击壤的平均相对误差分别为1.81%、3.46%、3.79%。研究成果可为提高甘蔗收获机入土切割负载压力预测控制系统的适应性、可靠性提供数据支持和理论依据,对其实际应用具有一定参考价值。

Design and experiment of the comb-brush harvesting machine with variable spacing for oil-tea camellia fruit

Oil-tea camellia tree is an important oil plant in China that has long flexible branches.The most challenging feature for the mechanized harvest of oil-tea fruits is that its flower and fruit grow synchronously.In order to improve the harvesting efficiency and avoid damaging the flower bud,a hand-held fruit harvesting machine with a variable spacing comb brush was proposed.The harvesting machine can generate three kinds of actuation to detach fruit when it runs.The main actuation results from the brushing of multiple comb fingers.The other two kinds of actuation result from the beating of comb fingers on the fruits and the branches.The finger spacing of the comb brush can be adjusted consequently through moving the spacing adjusting crossbar.Hence,when the finger spacing is smaller than the diameter of the oil-tea fruit,the fruit is brushed off,but the flower bud and leaf pass through the finger gap.When the finger spacing is bigger than the fruit diameter,the fruit stuck between the fingers is loosened to ensure the continuous operation of the machine.Nylon was used as the material of the brush finger to avoid damage,which can also reduce the overall weight.The dynamic simulation of the harvesting machine was carried out with ADAMS,and the acceleration of the front end of the comb finger and the variation of the finger spacing were analyzed.The prototype of the harvesting machine was built and tested in the field.Field experiment results showed that when the speed of the comb finger drive shaft was 480 r/min,the average harvesting percentage of oil-tea fruit was 80%,and the flower bud was seldom detached,which met the working requirements of oil-tea fruit harvesting.

Numerical simulation and experiment of grain motion in the conveying system of ratooning rice harvesting machine

The mixtures,grains,and residues in the ratooning rice harvesting machine need to be conveyed forward,backward,upward,and downward.Due to such operations,often accumulation and blockage take place at the intersection of a horizontal-vertical screw conveyor,resulting in low efficiency,high power consumption,and even grain damage.In this study,a CFD-DEM approach was applied to address the above problems.Firstly,a pneumatic conveying device was designed for ratooning rice,and then the motion of the rice grains and airflow field was analyzed in detail.The effects of different cross-sectional heights and lengths of the contraction section related to the mixing cavity were examined.Finally,the three-factor quadratic regression orthogonal rotational combination method was adopted in the experiment,and the fan velocity,filling coefficient,and speed of the horizontal screw conveyor were taken as test factors.The results showed that with the increasing cross-sectional height of the contraction section in the mixing cavity,the grain velocity decreased and the dispersity increased.With increasing length of the contraction section in the mixing cavity,the area of the high-speed airflow zone increased and the diffusion effect was enhanced.At the fan velocity of 2700 r/min,the filling coefficient was 0.41,the speed of the horizontal screw conveyor was 1173 r/min,and the outlet flow optimization index was the highest,which was 45.9%higher than that obtained without airflow.