Tag Archives: frequency

1944-1961 V. Bulgakov, I. Holovach, Z. Ruzhylo, V. Melnik, Ye. Ihnatiev and J. Olt
Theoretical study on forced transverse oscillations of root in soil with provision for soil’s elastic and damping properties
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Theoretical study on forced transverse oscillations of root in soil with provision for soil’s elastic and damping properties

V. Bulgakov¹, I. Holovach¹, Z. Ruzhylo¹, V. Melnik², Ye. Ihnatiev² and J. Olt³*

¹National University of Life and Environmental Sciences of Ukraine, 15 Heroyiv Oborony Str., UA 03041 Kyiv, Ukraine
²Dmytro Motornyi Tavria State Agrotechnological University, 18B Khmelnytsky Ave., UA 72310 Melitopol, Zaporozhye Region, Ukraine
³Estonian University of Life Sciences, Institute of Technology, 56 Kreutzwaldi Str., EE 51006Tartu, Estonia
*Correspondence: jyri.olt@emu.ee

Abstract:

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.

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987–992 J. Hart and J. Bradna
Suitability of 2.4 GHz and 5 GHz wireless communications in production processes
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Suitability of 2.4 GHz and 5 GHz wireless communications in production processes

J. Hart* and J. Bradna

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 00 Prague, Czech Republic
*Correspondence: janhart77@gmail.com

Abstract:

Today, it is increasingly modern to use wireless transmissions in production. It is possible to send information messages, control messages and it is often possible to access the technologies as IoT (the Internet of Things). The aim of this work was to find out which of the selected Wi-Fi frequencies is more suitable for use in syrup processing equipment. The evaluation was performed on the basis of attenuation and download speed at each frequency (2.4 GHz and 5 GHz bandwidth). These frequencies have been chosen due to their massive deployment for wi-fi networks that currently dominate wireless communications. Measurements were made downloading files on different frequency bands. Mean and maximum data throughput and signal strengths were also measured. By measuring, it has been found that when using 2.4 GHz wireless Wi-Fi technology, you can very often encounter strong interference effects. Despite the theoretically worse 5 GHz frequency spread, you can achieve up to 30% better data throughput on average. The results show the suitability of 2.4 and 5 GHz Wi-Fi technology. The main finding is that, despite the worse frequency spread of 5 GHz, it is more appropriate. Not only due to speed but also in the future due to better transmission capacities and future channel expansion.

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711–724 V. Bulgakov, V. Adamchuk, V. Gorobey and J. Olt
Theory of the oscillations of a toothed disc opener during its movement across irregularities of the soil surface
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Theory of the oscillations of a toothed disc opener during its movement across irregularities of the soil surface

V. Bulgakov¹, V. Adamchuk², V. Gorobey² and J. Olt³*

¹National University of Life and Environmental Sciences of Ukraine, 15, Heroyiv Oborony Str., UK 03041 Kyiv, Ukraine
²National Scientific Centre, Institute for Agricultural Engineering and Electrification, 11, Vokzalna Str., Glevaкha-1, Vasylkiv District, UK 08631 Kiev Region, Ukraine
³Estonian University of Life Sciences, Kreutzwaldi 56, EE51014 Tartu, Estonia
*Correspondence: jyri.olt@emu.ee

Abstract:

 The paper presents the main provisions of the new theory of oscillations of the versatile combined opener assembly of the breeding seed drill with a spring-suspended furrow opening toothed disc in the vertical longitudinal plane during its movement across irregularities of the soil surface. Basing on the improved design of the opener assembly, an equivalent schematic model has been developed, which takes into account the forces applied to the structural components of the opener, forces in the springs as well as the reaction of the soil acting on the toothed disc, the hoe-type seed conductor and the packing wheel. The system of differential equations has been set up, which describes the movement of the opener across irregularities of the soil surface depending on the opener’s design parameters and the kinematic modes of performing the drilling work process. The derived mathematical model makes it possible to determine the amplitudes and frequencies of the translational oscillations of the device in order to assess their impact on the drilling work process. The developed theory provides also tools for the assessment and lowering of the energy characteristics of the versatile breeding seed drill related to the oscillating movements of its openers in soil.

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