Theory of oscillations performed by tools in spiral potato separator

The aim of this study is to provide for the intensification of the process of removing impurities from the potato heap by oscillating devices, which takes place, when potato tubers are cleaned in the spiral separator during their lifting. The authors have devised a new design of the spiral separator, which can be used in the process of lifting potatoes from the soil. It comprises cantilever cleaning spiral springs, which in their simultaneously rotary and oscillatory motion clean and transport the potato tubers with good quality. However, the removal of impurities from the cleaning area and the cleaning of the side surfaces of potato tuber bodies from the stuck soil can be significantly more effective, if the spiral springs perform their oscillatory motions in the longitudinal and vertical plane during their operation more intensively. In order to achieve that, the authors have worked out a new theory of the oscillatory motion of the cleaning spiral working under the action of the potato heap. That promotes the intensification of the process of cleaning potato bodies from the stuck soil. The authors have generated a new partial differential equation, which describes the oscillations of the cantilever cleaning spiral. The PC-assisted numerical solving of the said differential equation and further numerical modelling have made it possible to obtain the analytic expressions of the relations between the change in the helix pitch distance of the cleaning spiral and its deformation, in particular, the simultaneous longitudinal extension and transverse bending. That result, in its turn, provided for finding the maximum limit amount of the above-mentioned deformation under the condition that the potato tubers may not fall through the spaces between the spiral turns, taking into account the design and kinematic parameters of the cleaning spiral itself, the material it is made of and the process-dependent mode of operation of the separator. As a result of the PC-assisted numerical modelling, it has been found that the total deflection of the spiral on its length varies within the range of 0 to 0.05 m under the following parameters: angular velocity of rotation of the spiral ω = 30 rad s-1, density of the material of the spiral ρ = 7,700 kg m-3, elastic modulus Е = 2∙1011 Pa, cleaning spiral bar stock radius r = 8.5 mm and a uniform load intensity of 1000 N m-1. Such variation ensures the good quality of cleaning and transportation of potato tubers. According to the results of the PC-assisted numerical calculations, the helix pitch distance of a cleaning spiral with the above parameters and the original helix pitch distance S = 48 mm, due to the spiral’s deformation under the proposed transverse oscillations, can change up to 54 mm, which makes impossible for potato tubers to fall out of the cleaning unit. Experimental studies fully support the results from the theoretical calculations to determine the displacement of the ends of the cleaning unit’s spiral springs

Theoretical and experimental research into impact of threshing tools in combine grain harvesters on quality of cereal crop seeds

The theoretical and experimental research into the micro-damaging of cereal crop seeds in the process of their harvesting by combine grain harvesters in relation to the strains, forces and stresses imparted to them by the threshing tools has been carried out. The propagation of deformations and cracks in the seeds as well as the nature of their strength and the damage that is sustained, when the critical load is applied, have been investigated. It has been established that the onset of cracks, the direction of their propagation and their quantity in the bodies of grain seeds depends in the majority of cases on the direction of action of the external forces and the specifics of the seeds’ internal biological properties. It has been established that the strength of the grain seed is, apart from the arisen cracks, also under the significant effect of the microtraumas in the germ, endosperm as well as the seed coat and shell. Theoretical calculations have been carried out on the PC and the effect that the drum and rotor threshing apparatus have on the deformation and damage sustained by cereal crop seeds has been substantiated. The said calculations and the obtained graphic relations support the results of the experimental investigations and prove that the macro- and especially micro-damage sustained by the seeds of winter wheat and rye is different, when they are threshed with the use of different types of threshing apparatus, which has a considerable impact on the final quality of the harvested cereal crop seeds. The results obtained in the experimental investigations, field and laboratory tests on the topic of the effect of mechanical loading on the sustained damage and quality of seeds indicate that the damage rate accounted for the work processes of the reaping and postharvest treatment of the cereal crop heaps of different winter wheat varieties with the use of rotor threshing apparatus is 3.1% as compared to the drum threshing apparatus – 6.4%, that is, 2 times lower. The total amount of the seeds with microtraumas collected in the hopper after threshing amounts to 23.0% and 54.0%, respectively, which is a significant difference. Similar results have been obtained in the experimental investigations on the effect of the equipment on the sustained damage and quality of seeds in the cleaning, chemical treatment and sowing of cereal crops

Mathematical model of cleaning potatoes on surface of spiral separator

ArticleCleaning potato tubers from soil impurities and plant debris after digging them out of soil is a topical problem in the work process of potato production. Therefore, the engineer ing of new designs of potato heap separators necessitates the further studying of them and the optimisation of their kinematic and design parameters, which must not only ensure the high quality of cleaning, but also rule out the possibility of damaging the tubers. The aim of this study is to determine the design and kinematic parameters of the improved design of the spiral potato separator, which will ensure the high quality of cleaning and rule out the possibility of damaging the tubers, on the basis of th e development of the new theory of potato tuber’s motion on the surface of the separator. An analytical study has been carried out resulting in the construction of the equivalent schematic model of the interaction between the potato tuber and separator, th e tuber being approximated by a material point on the surface formed by the two cantilevered spirals, which are the separator’s tools. The separator’s spirals are driven to rotate and at the same time they can perform oscillations in the vertical and axial plane under the action of the varying load generated by the continuous feeding of the potato heap for separation. In the model, the forces acting on the potato tuber’s body are applied to it, the coordinate axes that have been selected and appropriately o riented are shown. A system of equations has been set up for the constructed equivalent schematic model, comprising three differential equations of the potato tuber body’s motion on the surface of the trough formed by the two cantilevered spirals. The dete rmined kinematic and design parameters will allow to raise the quality of cleaning potato tubers from soil impurities and plant debris.

Theoretical study on forced transverse oscillations of root in soil with provision for soil’s elastic and damping properties

The topic of the paper is the theory of the forced transverse oscillations performed by the root fixed in the soil under the action of the harmonic perturbing force vectored at right angle to the root’s centreline and along the line of the translational motion performed by the lifter. On the basis of applying the Ostrogradsky-Hamilton variational principle and using the equivalent schematic model developed by the authors, the expressions have been obtained that allow to determine the amplitude of the forced transverse root body oscillations as function of the perturbing force amplitude value as well as the soil’s elastic deformation and damping coefficients. The ranges of the elastic soil deformation coefficient values, at which the resonant behaviour is observed, that is, at which the forced elastic root body oscillation amplitude value exceeds the tolerance limits, have been determined for the 10, 15 and 20 Hz frequencies of the perturbing force produced by the vibrational lifting tool. That said, the mentioned oscillation amplitude values can vary from 0.58 to 0.45 m, which is sufficient to result in the root breaking. Moreover, it has been proved that, with the increase of the perturbing force frequency, the resonant behaviour ranges shift towards the increased values of the elastic soil deformation coefficient. Therefore, such elastic soil deformation coefficient ranges should be avoided in case of the lifting tool design proposed in the paper. As regards the damping properties of the soil, it has been proved that they do not cause any resonance phenomena

ТРУДНОСТИ ДИФФЕРЕНЦИАЛЬНОЙ ДИАГНОСТИКИ СКЛЕРОДЕРМОПОДОБНОГО ПАРАНЕОПЛАСТИЧЕСКОГО СИНДРОМА И СИСТЕМНОЙ СКЛЕРОДЕРМИИ КАК ФАКТОРА ОНКОЛОГИЧЕСКОГО РИСКА

Системная склеродермия (ССД) – аутоиммунное заболевание соединительной ткани, характеризующееся прогрессирующим фиброзом кожи и внутренних органов. Характерные клинические признаки ССД могут маскировать онкологические заболевания, а паранеопластический процесс, в свою очередь, маскируется симптомами ССД. Цель исследования – показать необходимость дифференциальной диагностики склеродермоподобного паранеопластического синдрома и ССД как фактора онкологического риска. Материалы и методы. Проведен обзор и анализ данных научно-медицинской литературы. Результаты исследований и их обсуждения. Иммунные реакции, участвующие в патогенезе ССД, могут способствовать развитию онкологической патологии; поэтому пациенты с факторами риска развития заболевания требуют наблюдения за возможным развитием неопластического процесса. Пациенты с ССД и аутоантителами к РНК-полимеразе III имеют значительный риск развития рака. Риск канцерогенеза наиболее высокий в первый год после постановки диагноза ССД. С другой стороны, симптомы ССД могут быть маской различных видов рака. Паранеопластический склеродермоподобный синдром, непосредственно не связан с первичной опухолью и ее метастазами, а обусловлен сложными вторичными воспалительно-дегенеративными изменениями системного, локального либо дистантного характера, зачастую протекающими в виде проявлений “перекреста” (overlap) ревматического и опухолевого заболеваний. Предполагается, что раковые клетки могут индуцировать синтез вещества, инициирующего фиброз кожи и внутренних органов. Дифференциация между идиопатической формой ССД, склеродермоподобным паранеопластическим синдромом и развитием рака на фоне ССД вызывает множество трудностей. В статье представлен анализ дифференциально-диагностических мероприятий, предлагается схема скрининга для ведения пациентов с диагнозом ССД, находящихся в группе риска развития малигнизации. Выводы. Результаты анализа источников литературы доказывают актуальность углубленного изучения пациента с впервые выявленным склеродермоподобным синдромом, особенно в пожилом возрасте

Hemodynamic, hormonal and metabolic factors of fitness level at women

Background. It is known that the state of physical fitness of people who come to rehabilitation varies considerable range. We know also that this contingent characterized significant deviations in both sides of the gender and age norms of a number of parameters hemodynamic and autonomic regulation as well as of lipid and electrolytes exchange. Hence the assumptions listed parameters related to the state of the physical form. We set a goal by correlation analysis to detect hemodynamic and metabolic as well as hormonal factors of fitness level . Materials and methods. The object of observation were 29 women (average age 45 years with a range of 29-61 years) patients with chronic cholecystitis in remission who arrived at spa Truskavets’ (Ukraine) for rehabilitation . Physical form evaluated on a 5-point Ǻstrand scale using veloergometry. State of central hemodynamics was investigated by echocardiography. Plasma levels of cortisol, aldosterone, estradiol, TSH and triiodothyronine determined by ELISA, of triacylglycerides, cholesterol in lipoproteins of different density, uric acid, phosphate, calcium, magnesium, sodium and potassium determined by methods reflometry and spectrophotometry. In addition, determined levels of sodium and potassium in erythrocytes as well as the activity of Na,K-, Ca- and Mg-ATPase of erythrocyte membranes . Testing was performed twice. Results. Ascertained wide variety of fitness level on a 5- point Ǻ strand scale: un satisfactory in 15,5% , satisfactory in 64% and good in 20,5% . The method of correlation analysis revealed both positive ( levels in plasma estradiol , cholesterol of alpha- lipoproteines, triiodothyronine, magnesium and level in erythrocytes sodium ) and negative ( blood pressure , levels in plasma cortisol , triacylglicerides , TTH, uric acid and Mg- ATPase activity ) actotropic factors which together determine the level of physical fitness on 55 %. Conclusion. Identified actotropic factors may be viewed as objects of targeting of fitness rehabilitation in women

Justification of parameters for novel rotary potato harvesting machine

Received: March 6th, 2021 ; Accepted: May 12th, 2021 ; Published: May 14th, 2021 ; Correspondence: [email protected] authors have set an aim in relation to the development of a novel rotary potato harvesting machine design and the substantiation of rational design and process parameters for the clod crushing tools in the machine in order to improve its separation capacity. A novel design solution has been suggested for the process of crushing the two adjacent potato rows with the vanes of the vertical rotor and the expediency of using the methods of crushing clods in the two adjacent potato rows in advance has been justified. Also, the more rational placement of the clod crushing tools in the potato harvesting machine has been suggested. Following the completed research, the geometrical parameters of the vertical rotor have been substantiated, in particular, its diameter dр = 0.65–1.0 m and height hzag = 0.27 m. Additionally, the process parameters have been substantiated for some other tools crushing the clods, in particular, the angle of inclination of the share’s working face, which has to be equal to 10°, the elevator belt width bel = 1.05 m, the linear velocity of the belt Vp = 1.95 m s –1 , the belt agitation amplitude Аst = 18 mm. If the soil moisture content is equal to W = 18.4%, the soil separation rate rises insignificantly, when the rotor diameter increases within the range of 0.65–1.0 m, moreover, at Vm = 1.0 m s –1 it varies within the range of 85.3–87.2%, at Vm = 1.5 m s –1 – within the range of 87.0–92.7%, at Vm = 2.0 m s –1 – within the range of 86.0–89.1%. The best performance is achieved at a rotor rotation frequency of nр = 100 min–1 and a translational velocity of Vm = 1.5 m s –1 , in which case the soil separation rate S is equal to 93.5%. The tuber damage rate Pb decreases from 4.2% to 1.5%, as the rotor diameter dр increases from 0.65 m to 1.0 m, the translational velocity of the machine Vm – from 0.8 to 2.2 m s –1 at the rotor rotation frequency nр = 50–100 min–1

Research into geometric parameters of digging shares used for lifting sugar beet roots from soil with assistance of vibration

Received: February 2nd, 2021 ; Accepted: March 27th, 2021 ; Published: April 7th 2021 ; Correspondence: [email protected] of the important conditions in securing the high quality, when performing the work process of vibrational root lifting, is to avoid damaging the roots. It is obvious that the greatest probability of damaging and even breaking the lifted root arises, when the tool interacts with the root body during their first contact and in the time of the root passing in the throat between the operating shares. The aim of the study is to substantiate the rational design length for the working throat of the vibrational root lifter in its interaction with the sugar beet root while lifting the latter from the soil. As a result of the completed research, the minimum permissible tool oscillation frequencies have been determined for the specific values of the lifter’s translational velocity and the working throat rear part length, at which the event of the vibrational lifting tool gripping the root will occur at least one time. For example, when the length of the lifter’s working throat rear part is equal to 0.1 m and the oscillation frequency is equal to ν = 20.3 Hz, the satisfactory quality of the vibrational root lifting process is ensured, when the velocity of the translational motion performed by the vibrational lifter stays within the range of 1.3–2.55 m s –1 . In order to ensure the good quality of the vibrational root lifting process at the lifter’s translational velocity equal to V = 2.0 m s –1 and the frequency of its tool’s oscillations equal to ν = 10 Hz, it is necessary that the length of the lifter’s working throat rear part is equal to 0.2 m, at a tool oscillation frequency of 6.7 Hz - 0.3 m. As a result of the completed numerical calculations, the permissible values have been determined for the tool oscillation frequency, which can be recommended for the translational velocities within the range of 1.3–2.2 m s –1 , taking into account the limitation set for the tool oscillation frequency by the pre-condition of the guaranteed gripping of each root by the digging shares

Theory of motion of grain mixture particle in the process of aspiration separation

The paper describes the development of a mathematical model for the motion of a seed mixture particle in the aspiration channel of the separator after the particle passes the cone-shaped spreader and enters the workspace of the aspiration channel in the pneumatic dynamics and vibration unit devised by the authors. The unique feature of the proposed new design is the presence of the central pipe with sail members in the aspiration channel. The sail members in the air stream generate the self-oscillatory mode of motion of the central pipe, which results in the efficient separation of the grain seed mixture into the required fractions. On the basis of the prepared equivalent schematic model, the differential equations of the motion of a seed mixture particle in the process of aspiration separation have been generated. Basing on the results of the PC-assisted numerical modelling of the motion paths, on which the material particles (seeds) of the heavy and medium fractions travel, it has been established that they move on different courses, and the course of the heavy fraction seeds is such that, after they pass the cone-shaped spreader and advance further in the air stream through the space of the aspiration channel, they move closer to the pipe of the aspiration channel. Also, their velocities and accelerations are greater than the same kinematic parameters of the medium fraction seeds. The seeds of the light fraction move upwards under the action of the air stream and leave the aspiration separator at its top

Motion stability estimation for modular traction vehicle-based combined unit

One of the promising ways of efficiently applying high power intensity tractors is their design and utilisation in the form of modular traction vehicles comprising two modules: the power module and the process module. In order to provide for the sufficient manoeuvrability of the modular traction vehicle, when its process module passes a turn, the latter is equipped with vertical and horizontal hinge joints. The freedom of the process module’s rotation with respect to the power module in the horizontal plane through the agency of the above-mentioned vertical hinge joint is restrained by a hydraulic cylinder, in which the chambers above and below the piston are connected via a throttle valve with a hydraulic resistance coefficient of about 1.03×106 N m s rad–1 . This paper is concerned with the theoretical and experimental research into the stability of motion (on turn spaces as well as in the transport mode) of a modular combined unit, when its velocity changes and/or the slip resistance coefficient of the tyres on the wheels of the process module, in which the hydraulic cylinder is equipped with a throttle valve with the above-mentioned hydraulic resistance coefficient, changes