The theory of cleaning the crowns of standing beet roots with the use of elastic blades

ArticleA standing beet root crown cleaner has been designed. The design comprises the vertical drive shaft that carries two flat elastic cleaning blades installed on axes and connected through the articulated connection. The aim of the study was to develop the new theory of cleaning the crowns of standing roots with the use of an elastic blade installed on the vertical drive shaft in order to determine its optimal design and kinematic parameters. The first step was to design an equivalent schematic model of the interaction between the elastic cleaning blade installed on the vertical drive shaft and the spherical surface of the beet root fixed in the soil. The interaction between the blade and the root's crown took place at the point, where all the forces that can arise during such interaction are applied. A three-dimensional coordinate system was set and the design and kinematic parameters of the considered interaction were designated. Using the original differential equations projected on the set coordinate axes, the system of four nonlinear differential equations of the three-dimensional motion of the elastic cleaning blade on the spherical surface of the root crown was set up, then it was transformed into the system of two differential equations in the normal form. Further, to determine the force that strips off the remaining haulm, which is part of the obtained system of differential equations, the problem of its analytical determination was solved separately. Also, the additional equivalent schematic model of the interaction between the elastic blade as a cantilever beam and the root's crown was designed, the differential equation of the beam's deflection curve (taking into account the beam's simultaneous bending and twisting) was set up and, on the basis of it, the projections of the stripping force on the coordinate axes were found. The values of the force were substituted in the earlier obtained system of differential equations

Experimental research into new harrowing unit based on gantry agricultural implement carrier

Received: October 6th, 2020 ; Accepted: December 11th, 2020 ; Published: December 16th, 2020 ; Correspondence: [email protected] the point of view of energy saving, research into agricultural gantry units equipped with new implements specially adapted for operation in such systems and capable of efficiently functioning in controlled traffic (permanent lane) and wide span (gantry) systems is an important and topical issue in soil tillage science. The range of wide span systems includes harrowing units for fallow land tillage. This paper describes the experimental determination of the operating characteristics of the harrowing unit, in which a gantry implement carrier propels harrows for fallow land tillage, for the purpose of establishing the compliance of their parameters with the fundamental principles of the effective implementation of the controlled traffic and wide span soil management. The experimental investigations were done using strain-gauge and control-and-measuring equipment with analogue-to-digital conversion of the signals received from the sensing elements. An agricultural wide span unit with a track width of 3.5 m and harrows for fallow land tillage were investigated. The results show the harrowing unit is well adapted to operation in controlled traffic and wide span soil tillage systems and delivers high quality performance of the harrowing process. The latter effect is also due to the fact that the gantry travels on the compacted tracks which have a few surface irregularities compared to cultivated soil. The coefficient of variation of the draught force applied to the hook of the gantry during harrowing operations did not exceed 10%. This is evidence of the high stability (low variability) of the harrowing process, which has a positive effect on the motion stability of the harrowing unit based on the gantry tractor

Quasi-freestanding and single-atom thick layer of hexagonal boron nitride as a substrate for graphene synthesis

We demonstrate that freeing a single-atom thick layer of hexagonal boron nitride (hbn) from tight chemical bonding to a Ni(111) thin film grown on a W(110) substrate can be achieved by intercalation of Au atoms into the interface. This process has been systematically investigated using angle-resolved photoemission spectroscopy, X-ray photoemission and absorption techniques. It has been demonstrated that the transition of the hbn layer from the "rigid" into the "quasi-freestanding" state is accompanied by a change of its lattice constant. Using chemical vapor deposition, graphene has been successfully synthesized on the insulating, quasi-freestanding hbn monolayer. We anticipate that the in situ synthesized weakly interacting graphene/hbn double layered system could be further developed for technological applications and may provide perspectives for further inquiry into the unusual electronic properties of graphene.Comment: in print in Phys. Rev.

Theory of retaining potato bodies during operation of spiral separator

ArticleThe increase of the efficiency and quality of performance of the work process of potato heap separation can be achieved by means of improving the design of the vibrational spiral separator and substantiating theoretically its rational parameters under the condition of eliminating damage to the potato tubers. An equivalent schematic model of the interaction between the potato tuber and the surface of the cantilever spiral springs has been devised. On the basis of the model, the kinematic characteristics of the tuber’s flight and its impact contact with the elastic surface of the over mounted rebounding conveyor have been investigated. A new analytical mathematical model of the potato tuber’s flight from the surface of the spiral separator and its subsequent encounter with the rebounding conveyor mounted above the spiral springs has been developed. New analytical dependences have been obtained for finding out the distance and height of the potato tuber’s flight to the point of impact contact as well as the trajectory equation fo r the travel to the said contact, which makes it possible to obtain the kinematic constraints imposed on the allowed rate of travel under the condition of not damaging the tuber. On the basis of the obtained analytical dependences, the kinematic parameters of the improved design of the spiral potato harvester separator in its interaction with a potato tuber under the condition of not damaging the latter have been investigated

Theoretical research into the motion of combined fertilising and sowing tractor-implement unit

ArticleA mathematical model has been developed representing the motion of a seed drill combination simultaneously performing the preceding banded placement of mineral fertilisers. Such a combined unit comprises the gang-up wheeled tractor, the fertiliser distribution module behind the tractor attached to it with the use of a hitch and intended for the banded placement of mineral fertilisers and the grain drill behind the fertiliser distribution module attached to it also with the use of a hitch. For the components of this dynamic system the coordinates of their centres, their masses as well as the external forces and the reactions of the soil surface applied to them have been determined. In order to use the original dynamic equations in the form of the Lagrange equations of the second kind, the generalised coordinates and kinetic energy relations have been determined. Following the necessary transformations, a system of six differential equations of motion has been generated, which characterises the behaviour of the combined machine unit during its plane-parallel motion. In this system, two line coordinates and one angular coordinate characterise the behaviour of the propulsion and power unit (wheeled tractor), while three angular coordinates characterise the rotations of the draft gear and the centres of the machines integrated with its use

Theory of impact interaction between potato bodies and rebounding conveyor

ArticleIn order to increase substantially the quality of the potato heap separation, it is necessary to carry out the theoretical substantiation of the spiral separator’s parameters with regard to the impact interaction between the product and the tools of the un it under the condition of not damaging the tubers. An equivalent schematic model of the impact interaction between a potato tuber and the surface of the rebounding conveyor has been devised. Taking into account the coefficient of restitution of the tuber’s velocity in case of an impact, new analytical expressions have been obtained for determining the magnitude and direction of the potato tuber’s velocity after the impact. They provided the basis for applying the principle of momentum at impact and obtainin g the analytical expressions that allow determining the impact impulse and impact force at the impact of the tuber on the surface of the rebounding conveyor and, eventually, the dynamic constraints on the permitted velocity of the tuber prior to the impact interaction under the condition of not damaging it. A new analytical mathematical model of the impact interaction of the potato tuber during the potato heap separation has been developed. On the basis of the obtained theoretical results, studies have been carried out on the rational kinematical parameters of the high - quality performance of the above - mentioned work process under the condition of keeping the potato tubers undamaged