Tag Archives: mathematical model

1142–1149 T. Saller, D. Herak, C. Mizera and A. Kabutey
Linear compression behaviour of oil palm empty fruit bunches
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Linear compression behaviour of oil palm empty fruit bunches

T. Saller, D. Herak*, C. Mizera and A. Kabutey

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Mechanical Engineering, Kamycka 129, CZ16500 Prague, Czech Republic
*Correspondence: herak@tf.czu.cz

Abstract:

The study describes the mechanical behaviour of oil palm empty fruit bunches (EFB) as a promising product for pyrolysis production. The EFB samples mixture of moisture content 6.3 ± 0.3 (% d.b.) were grouped into different fraction sizes of 10, 20, 40 and 100 mm. The initial pressing height of each fraction size was measured at 60 mm and compressed at a maximum force of 4,500 N and speed of 10 mm min-1 to obtain the force-deformation dependencies using the universal compression machine and pressing vessel of diameter 60 mm with a plunger. Deformation, deformation energy, volume energy and strain were calculated. While deformation decreased with fraction sizes, deformation energy increased. The deformation energies at fraction sizes from 10 mm to 100 mm indicated energy savings of approximately 23%. The optimal fraction size in relation to energy efficiency was observed at 10 mm. The tangent model accurately described the mechanical behaviour of the EFB samples mixture. The results provide useful information for the design of optimal technology for processing EFB for energy purposes.

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2217-2244 Y. Tsytsiura
Formation and determination of the individual area of oilseed radish leaves in agrophytocenosises of different technological construction
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Formation and determination of the individual area of oilseed radish leaves in agrophytocenosises of different technological construction

Y. Tsytsiura

Vinnytsia National Agrarian University, Faculty of Agronomy and Forestry, Sonyachna street 3, UA21008 Vinnytsia, Ukraine
Correspondence: yaroslavtsytsyura@ukr.net

Abstract:

For the successful control of the production process, determining the leaf area is a basic requirement. In this context, it is important to determine the regularities of leaf formation within the plant, considering technological parameters of agrophytocenosis construction. These are the important issues covered in this paper based on the years of research conducted between 2013 and 2018 on three cultivars of oilseed radish: one of the poorly explored members of the cruciferous family of multipurpose use. The conducted researches allowed to distinguish features of longline leaf formation of oilseed radish cultivars and mathematically describe features of formation of their area, length and width at the early flowering phase according to the Richards growth curve. The peculiarities of formation of individual leaf area depending on the combination of the variations of the stand density and fertilization in the context of the recommended process regulation of oilseed radish cultivation are also determined. It has been proved possible to use a non–destructive method of determining the individual leaf area of oilseed radish, basing on the evaluation of 29 models, using the following formula S = 7.9316–2.3613L + 0.6897 (LW)+0.0458L2–0.0005 (LW)2 (under the following test parameters of the model: R2 0.9106; RMSE 9.75; d 0.956; BIAS –0.1523).

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18–37 V. Bulgakov, S. Nikolaenko, I. Holovach, V. Adamchuk, S. Kiurchev, S. Ivanovs and J. Olt
Theory of grain mixture particle motion during aspiration separation
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Theory of grain mixture particle motion during aspiration separation

V. Bulgakov¹, S. Nikolaenko¹, I. Holovach¹, V. Adamchuk², S. Kiurchev³, S. Ivanovs⁴ and J. Olt⁵*

¹National University of Life and Environmental Sciences of Ukraine, 15 Heroyiv Oborony Str., UA 03041 Kyiv, Ukraine
²National Scientific Centre, Institute for Agricultural Engineering and Electrification, 11, Vokzalna Str., Glevakcha – 1, Vasylkiv District, UA08631 Kiev Region, Ukraine
³Dmytro Motornyi Tavria State Agrotechnological University, Ukraine
⁴Latvia University of Life Sciences and Technologies, 2 Liela Str., LV-3001 Jelgava, Latvia
⁵Estonian University of Life Sciences, 56 Kreutzwaldi Str., EE51006 Tartu, Estonia
*Correspondence: jyri.olt@emu.ee

Abstract:

The practice of separating grain mixtures with the use of the difference in the aerodynamic properties of their components has proved that the process of separating mixtures in the aspiration separator is the most promising one with regard to the improvement of quality and intensification of production. The authors have developed a new improved design of aspiration seed separators, in which the work process of separating seed material is performed with the use of vibration processes. In this seed material separator, the constant force air flow that acts on the sail members on the central pipe of the separator, when seeds are fed for processing, generates self-excited oscillations in the pipe, which produces centrifugal forces of inertia in the seed feeding system. As a result of the mentioned effect, the propelling force in the process under study substantially increases, accelerating the seeds of different fractions, which differ in their masses, to different velocities. The motion paths of the seed particles change accordingly, heavier particles moving closer to the vertical axis of the aspiration channel, which provides for increasing the efficiency of separation of the seeds of different fractions from each other. In this paper, a new mathematical model is developed for the motion of a seed mixture material particle in the operating space of the separator’s aspiration channel. The mathematical modelling of the process of vibration and aspiration separation has indicated that the separation of the motion paths of the medium and heavy fractions takes place within the range of 20–40 mm; the flying speed of the particles is equal to 3.2–8.0 m s–1, respectively; and their acceleration is equal to 1.8–3.3 m s–2, which provides the necessary conditions for the accurate and high quality separation into the required fractions. In view of the found differences between the kinematic characteristics of the separated fractions of the grain mixture, the diameter of the pipeline for the medium fraction is to be within the range of 90–100 mm, for the heavy fraction – 50–70 mm.

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1927–1941 A. Kabutey, D. Herak, C. Mizera and P. Hrabe
Theoretical analysis of force, pressure and energy distributions of bulk oil palm kernels along the screwline of a mechanical screw press FL 200
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Theoretical analysis of force, pressure and energy distributions of bulk oil palm kernels along the screwline of a mechanical screw press FL 200

A. Kabutey¹*, D. Herak¹, C. Mizera¹ and P. Hrabe²

¹Czech University of Life Sciences Prague, Department of Mechanical Engineering, Faculty of Mechanical Engineering, Kamycka 129, CZ165 00 Prague, Czech Republic
²Czech University of Life Sciences Prague, Department of Material Sciences and Manufacturing Technology, Kamycka 129, CZ165 21 Prague, Czech Republic
*Correspondence: kabutey@tf.czu.cz

Abstract:

The present study is a follow-up of the previously published study on the mathematical description of loading curves and deformation energy of bulk oil palm kernels under compression loading, aimed at determining theoretically the amounts of force, pressure and energy along the screw lamella positions ??? of the screw press FL 200 by applying the tangent curve mathematical model and the screwline geometry parameters (screw shaft diameter, screw inner and outer diameters, screw pitch diameter and the screw thickness). The fitting curve value ?? of the tangent mathematical model was further examined at ?? = 2 and ?? = 3 by identifying the force, deformation, stress and compression coefficients at varying vessel diameters ?? and initial pressing heights ?? of the bulk oil palm kernels. Based on the results of the stepwise regression analysis, the amounts of the theoretical deformation energy ??? in linear pressing as well as the theoretical force ??, pressure ?? and energy ??? of the screw press FL 200 were statistically significant (P-value < 0.05) or (F-value > significance F) in relation to the predictors (??, ??, ?? and ???). The coefficient of determination (R2) values between 61 and 86 % were observed for the determined regression models indicating that the responses ???, ??, ?? and ??? can accurately be predicted by the corresponding predictors. The normal probability plots of the responses approximately showed a normal distribution.

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33–48 V. Bulgakov, S. Pascuzzi, S. Nikolaenko, F. Santoro, A. Sotirios Anifantis and J. Olt
Theoretical study on sieving of potato heap elements in spiral separator
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Theoretical study on sieving of potato heap elements in spiral separator

V. Bulgakov¹, S. Pascuzzi², S. Nikolaenko¹, F. Santoro², A. Sotirios Anifantis² and J. Olt³*

¹National University of Life and Environmental Sciences of Ukraine, Heroyiv Oborony street 15, UA03041 Kiev, Ukraine
²Department of Agricultural and Environmental Science (DiSAAT), University of Bari Aldo Moro, Via Amendola, 165/A, Bari, IT70125, Italy
³Estonian University of Life Sciences, Institute of Technology, Kreutzwaldi 56, EE51006 Tartu, Estonia
*Correspondence: jyri.olt@emu.ee

Abstract:

One of the principal problems in the harvesting of potatoes is the cleaning of the lifted heap from soil and plant impurities. The low quality in the performance of this harvesting work process operation is the main cause of the withdrawal from fields of considerable amounts of fertile soil. In order to facilitate choosing the optimal parameters for the new design of the spiral potato heap cleaning unit, a mathematical model of sieving the soil impurities through its cleaning spirals has been developed. The obtained analytical expressions have been solved with the use of a PC and the results have been used for plotting the graphic relations between the parameters of the examined process of a variable-mass body’s motion on the surface of a spiral, which have made it possible to select the optimal design and kinematic parameters of the spiral cleaning unit under consideration. The obtained graphic relations indicate that the rate of sieving in the spiral separator depends on many factors, including the initial mass, the design dimensions (spiral’s radius, helix angle etc.), the frictional properties of the surface, the angular parameters of the position of the potato heap elements on the spiral’s surface, and the angular velocity of the rotational motion of the spiral roll itself.

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481–490 A. Kešner, R. Chotěborský, M. Linda and M. Hromasová
Methodology of the stress detemination in the tool module during the work of the agriculture machine
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Methodology of the stress detemination in the tool module during the work of the agriculture machine

A. Kešner¹*, R. Chotěborský¹, M. Linda² and M. Hromasová²

¹Czech University of Life Sciences Prague, Facult of Engineering, Department of Material Science and Manufacturing Technology, Kamýcká 129, CZ165 21 Prague, Czech Republic
²Czech University of Life Sciences Prague, Faculty of Engineering, Department of Eletrical Engineering and Automation, Kamýcká 129, CZ165 21 Prague, Czech Republic
*Correspondence: kesner@tf.czu.cz

Abstract:

Machine construction is designed using by mathematical models. The frame is a fundamental part of an agricultural soil cultivation machine so that forces were transferred during transport and machine work to frame. The stress in the machine frame is important to know for the best frame design of the machine. The mathematical model included measured strain can able to design or detect deficiencies on the machine frame. Due to the transfer of forces from the tools, stress is created in the machine frame. High requirements are placed on the determination of boundary conditions for mathematical models in agricultural machinery. Various types, sizes and equipment of agricultural tools significantly affect the transfer of drought force to the machine. The direction and magnitude of the forces, that are caused by agricultural tools, it is important to find out. Ansys mechanical solver have been used to determination strain like response of frame from chisel module. The results can be used as a boundary condition for mathematical models.

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866–876 E. Shalavina, A. Briukhanov, R. Uvarov, E. Vasilev
Method for selection of pig manure processing technologies
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Method for selection of pig manure processing technologies

E. Shalavina*, A. Briukhanov, R. Uvarov, E. Vasilev

Institute for Engineering and Environmental Problems in Agricultural Production – IEEP, Department of Environmental Engineering of Agricultural Production, 3, Filtrovskoje Shosse, p.o. Tiarlevo, Saint Petersburg-Pavlovsk RU196625, Russia.
*Correspondence: shalavinaev@mail.ru

Abstract:

The criteria, which take into account both economic and environmental indicators, were suggested for assessment of technologies and selection of the most reasonable solution. The method of Pareto optimization was applied. Technologies suited for the North-West Russia were considered to design a mathematical model and to obtain the required indicators for the criteria calculation. The technology of multi-stage processing of pig manure with cyclic sedimentation tanks was studied in more detail based on a separate, specially designed three-level mathematical model. The objective function was the eco-economic index of nitrogen, which is the ratio between the economic benefit from the marketed yield increment and the costs of nutrients retention in the organic fertilizers applied to soil under the harvested crop yield. The resulting simulation data were substantiated by experimental studies. A mathematical model and an algorithm for selecting the best-suited technology were designed. As the calculation process involved a large bulk of data, the WEB programming was used. Simulation results demonstrated 90% accurate choice of technology. The designed model was tested for the conditions of a pig complex in Leningrad Region with the manure output of 150 t per day and no own farmland for organic fertilizer application. Calculations proved the economic and ecological effectiveness of the multi-stage processing of pig manure: operating costs per one ton of produced organic fertilizer were reduced 1.8 times, fuel costs – 1.4 times and labour costs – 3.3 times. The chosen technology also featured higher ecological safety coefficient. Estimated ecological and economic effect of introduction of this technology amounted to 5936 thousand roubles per year.

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1321-1331 V. Kirsanovs, A. Žandeckis and C. Rochas
Biomass gasification thermodynamic model including tar and char
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Biomass gasification thermodynamic model including tar and char

V. Kirsanovs*, A. Žandeckis and C. Rochas

Institute of Energy Systems and Environment, Riga Technical University, Azenes iela 12/1, LV-1048 Riga, Latvia
*Correspondence: vladimirs.kirsanovs@rtu.lv

Abstract:

Biomass gasification is a thermochemical process in which feedstock is heated to high temperatures in a condition of absence of oxygen. As a result, biomass is converted into the combustible syngas, which typically consists of carbon monoxide (CO), carbon dioxide (CO2), hydrogen (H2), methane (CH4), nitrogen (N2) and water vapour (H2O). Biomass gasification process simulation plays an important role in gasification process comprehension and optimization. Typically, gasification models have only one output flow in the process mass balance, which represents the amount of the produced syngas. Tar and char also are significant products of gasification process. This study presents a thermodynamic biomass gasification model. The fundamental distinction of the proposed model, comparing to other available models, is that tar and char also are taken into account in developed model. Gasification process is affected by many factors. Similarly, the amount of produced tar and char can significantly vary depending on gasifier operation conditions. Literature review on the previous studies is done to determinate the most critical factors which affect tar and char formation. Results show that temperature in the gasifier, equivalence ratio and fuel properties have dominant effect on the products yield. Two regression models are elaborated to present the amount of the produced tar and char depending on independent variables. The achieved mathematical equations are added to the developed thermodynamic model of the gasification process. Biomass gasification process is simulated with different values of fuel moisture and equivalence ratio. The results show that produced syngas amount, calorific value and biomass energy conversion efficiency are more realistic after tar and char including in the model.

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939-947 D. Herak
Analysis of mechanical behaviour of Jatropha curcas L. bulk seeds under compression loading with aid of reciprocal slope transformation method and tangent curve method
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Analysis of mechanical behaviour of Jatropha curcas L. bulk seeds under compression loading with aid of reciprocal slope transformation method and tangent curve method

D. Herak

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Mechanical Engineering, Kamycka 129, 16521, Prague, Czech Republic; e-mail: herak@tf.czu.cz

Abstract:

This study is focused on the utilization of the reciprocal slope transformation method (RST) and tangent curve method (TCM) for description of mechanical behaviour of Jatropha bulk seeds under compression loading. The experimental data derived from a compression test was done using compression device and pressing vessel with diameter 60 mm at compression speed of 1 mm s−1 and compressive force between 0 kN and 100 kN. Measured dependency between compressive force and deformation was fitted by RST method and TCM method and they were statistically analysed by ANOVA. Comparison of both methods in individual pressing regions is an integral part of this manuscript. It was determined that reciprocal slope transformation method describes precisely the beginning of deformation characteristics and it can cover the reorganizing process in the bulk seeds. From the conducted study it also follows that tangent curve method is suitable for description of mechanical behaviour at bulk deformations in which the reorganization process in the bulk seeds is finished yet.

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81-88 J. Priekulis and K. Vartukapteinis
Rational application of mobile machinery for slurry transportation and distribution
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Rational application of mobile machinery for slurry transportation and distribution

J. Priekulis* and K. Vartukapteinis

Faculty of Engineering, Latvia University of Agriculture, J.Čakstes bulv. 5,LV-3001 Jelgava, Latvia; *Correspondence: juris.priekulis@llu.lv

Abstract:

The article describes the most important versions of slurry transportation and distribution using mobile machinery. Calculation methods of organisation of work, including formulae calculation and description of work planning procedures are given. The principles of mathematical model development that are used for calculation and analysis of slurry transportation and distribution technological parameters are discussed.

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