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• A simple model for fruit tree shaking harvest

  33-36.

  Z. Láng

  Views:

  211

  A tree structure model was composed of trunk and main roots. It included a mass, spring and damping element, all of them reduced to the external end of the main roots. The model parameters, such as virtual turning centre, reduced mass, spring constant and clamping coefficient were measured on a real cherry tree. The model was than virtually shaken at 80 cm trunk height and acceleration and displacement amplitudes versus shaking frequency were calculated. The real cherry tree was shaken also at 80 cm trunk height by an inertia type shaker machine and the same data were recorded. The acceleration amplitude vs. frequency and displacement amplitude vs. frequency functions were similar for the virtual and real tree which proves the ability of the model. Power demand and specific power demand was then calculated in function of shaking frequency. The diagrams show that the shaking frequency of 12-14 Hz, of the practice is not the most efficient concerning amplitude, but is probably necessary from the point of view of acceleration needed to detachment of fruits.

• Mass and displacement relationships of tree shakers

  36-40.

  E. Horváth

  Views:

  116

  The degree of mechanically harvested fruit removal by shakers is determined by the displacement pattern, the frequency and the amplitude of shaker mechanism attached to the tree trunk. The displacement pattern is derived from the structural setup of the vibration mechanism, the frequency can easily be adjusted by the rev/min (rpm) of the rotating masses. More problems are arising in determining the dynamics of the tree-shaker system. Among others the amplitude of the attachment point and its components, the effective masses reduced to the attachment point.

  Recent work gives some new insight into the tree-shaker dynamics including new calculation methods to determine the displacement components and the effective masses reduced to the attachment point. A fully new approach is given to include the vibrating soil mass into the total effective mass. The assumptions are supported and verified by laboratory and field measurements.

   

• Cost-effective plantlet production and wintering method of virginia fanpetals (Sida hermaphrodita L. Rusby)

  137-141.

  E. Kurucz

  G. Antal

  J. Popp

  M. G. Fári

  Views:

  218

  The main goal of this research was to work out programmable, cost-effective and industrial scale technologies of mass propagation from the seeds of rootstock nurseries of undomesticated American populations of Sidahermaphrodita. During our previou`s seed treatment experiments, it was concluded that around 60% of the Virginia fanpetalsseeds collected during the four cropyears can be considered as high quality, infection-free, normally imbibing and germinating seeds (Kurucz et al., 2013a,b). The experiments performed with the nurse-in-tray method developed by us showed that the summer-autumn nurse-in-tray plantlet production and unprotected wintering of Virginia fanpetals with properly pre-treated and fractioned seeds is a promising new method. No weeds appear between the plants, but only on the side of the cases during plantlet production. The investment cost of the method is minimal. There are no heating costs and this phytotechnique can be easily and properly mechanised. Plantlet production can be performed near the large-scale plots. After exploring the root and shoot system, it was concluded that the nurse-in-tray method is suitable for producing plantlets with hardened and strong roots. Scheduled plantlets can be produced in an industrial scale volume by the time of early spring (March) plantlet planting. The excavateof plantlets can be flexibly adjusted to the needs; they may even grow in the plantlet cases for a whole year. We think that these innovative plantlet production and wintering methods which are suitable for large-scale use will make Virginia fanpetals a proper feedstock for the constant supply of the Biomass Supply Chain both in Hungary and in European countries which are in the same climate zone. The comparative analysis of the costs of this procedure calls for further research.

• Evaluation of a simple fruit tree structural model

  123-126.

  Z. Láng

  Views:

  183

  A simple three element tree structure model of Lang, 2006 was tested in plum orchard using two different inertia fruit tree shakers. The first was a slider crank type one; the second had rotating eccentric weights. The parameters of both were chosen to give similar frequency and amplitude output in average orchard conditions. Orchard experiments were carried out shaking the trees with both machines at several frequencies and shaking heights. The measured acceleration and amplitude values were plotted on diagrams together with the calculated acceleration and amplitude curves of the fruit tree-shaker machine model. Choosing the right fruit tree parameters, such as apparent spring constant, damping coefficient, reduced trunk mass and coefficient of elasticity of the trunk the measured and calculated values coincided well. This proves the ability of the fruit tree model for optimising the shaker parameters to any given orchard.