• ## Theory of vertical oscillations of a frontally mounted tops harvesting machine

pg(s) 41-46

To establish influence of kinematic and constructive parameters of tops-harvesting machine on quality of a continuous cut of the massif of tops at oscillations in the longitudinal-vertical plane of its tops-cutting device at frontally mounted machine on a wheeled row-crop aggregate tractor. Used modeling methods based on higher mathematics, theoretical mechanics, solving a system of differential equations and compiling programs and numerical solutions on a PC. An equivalent scheme has been developed for a tops-harvester mounted on a wheeled tractor in front of it on its oscillations in the longitudinal-vertical plane, considering all the forces that arise, taking into account the kinematic excitation that occurs when moving along soil surface definitions also due to the elastic-damping properties of its support-copying wheels. For the specified equivalent scheme, on the basis of application of initial equations in the form of Lagrange of the 2nd kind, on the chosen generalized coordinates, the system of two nonlinear differential equations of oscillatory motion of the tops-harvesting machine is received. According to the analytical transformations, the solution of this system was obtained, which made it possible to obtain the f inal expressions for determining the amplitude and circular frequency of natural and forced oscillations of the tops-harvesting machine. Numerical calculations of the received expressions on the made program on the personal computer are carried out . According to the results of numerical simulation, the final expression was obtained, which allowed to determine the vertical displacements of the end of the rotary cutting unit during the oscillations of the topping machine in the longitudinal-vertical plane. Numerical calculations on the PC of the received expression gave the chance to construct graphic dependences which establish dependences of amplitude of the specified oscillations depending on constructive parameters of the tops-harvesting machine, and also characteristics of roughnesses of a soil surface and elasticdamping properties of copying wheels.

• ## Research on reducing the impact of sloshing on the walls of a liquid manure tank of partially filled in a braking manoeuver

pg(s) 47-51

The appearance of violent liquid sloshing on the walls of the tank can cause great problems to those who handle these liquid manure tank that spread coarse residues from animal farms. This violent sloshing occurs when the tank is partially filled with liquid product. This movement of the liquid inside the tank imposes pressure along the walls when the tank is not full, thus causing instability on the entire structure during its movement on agricultural land. In this work was used a tanker that transports and spreads on the ground animal manure from a cattle farm. The modelling of the tank was done with the Solidworks program and the numerical analysis of the impact of the liquid tension distributions on the tank through with Ansys-CFX. The tanker moves at a constant speed (v=5m/s), after which it is subjected to a braking manoeuver. In this paper is analyzed behaviour and effect the impact of tensions distribution on the walls of the tank, when it has or does not have baffles.

• ## Digital agriculture: The experience of Ukraine

pg(s) 52-56

For example of the implementation of an educational project to train students in the field of digital agriculture technologies is given. The project was implemented at the Dnipro State Agrarian and Economic University. The equipment was provided by LLC “Agro KMR” for information. An overview of software of Ukrainian and foreign production working in the field of digital agriculture is given. The advantages of using digital agriculture are shown. As an example, the implementation of the functions of differentiated sowing of sunflower by the unit Case IH Magnum 380 + Horsch Maestro 36.50SW, for which sowing maps were developed by students, is given. Sowing was performed in real conditions
It is shown that farmers and owners of agricultural holdings should be more interested in the functioning of such a project than universities – because it significantly optimizes and automates production. Without such technologies in the coming years, agricultural enterprises will begin to lose competitiveness.

• ## Evaluation of effects of biofuels blends on performance and emissions of diesel engine

pg(s) 57-60

Growth of the economy and living standards of the population increase the need of people’s and goods transportation by sea, railroads, the air, and highways. As a result, increases the need to use more ships, trains, airplanes, heavy-duty trucks, self-powered machines, city busses, and light-duty passenger cars. Unavoidably increases the demand of the fuel to be consumed, however the natural oil – resources are largely exhausted over hundreds of years. Moreover, the increased consumption of a fossil-origin fuel creates the urgent environment pollution problems and climate change. The automotive air-pollution problem emerged already aim of this article was to
investigate the influence of three-component fuel on the efficiency and emission performance of a diesel engine. The results obtained during the research are presented, which are investigated with a single-cylinder diesel engine “ORUVA F1L511”. The study examines diesel fuel and fuel blends J5Bu5, J5Bu10 and J5Bu15. The results obtained in the study are comparable. Engine load characteristics were recorded at n = 2000 rpm. The study found that the lowest carbon monoxide (CO) emissions (163ppm) were obtained by using J5Bu5 fuel blend. Maximum nitrogen oxide (NOx) emissions were obtained with the engine running on diesel fuel (1839ppm). The lowest NOx emission was obtained with the engine running on a three-component J5Bu15 fuel blend (1643ppm). The highest opacity was obtained when the engine was fuelled with 100% diesel fuel and at full load.

• ## Operational properties of diesel fuel with the addition of rapeseed oil esters

pg(s) 61-63

The article is devoted to the study of performance indicators of diesel fuel with the addition of rapeseed oil ether. To do this, the study used diesel fuel of Euro 5 grade “L” and the following dietary supplements: rapeseed oil methyl ester and rapeseed oil isopropyl ester. In the resulting biofuels the corresponding physical and chemical properties were determined. Based on the results of research, it was found that the complex of quality indicators of diesel fuel of petroleum origin and samples of rapeseed oil esters slightly differs from the indicators of petroleum diesel fuel, and, also, number of indicators of environmental properties are better than those of fuel of petroleum origin.

• ## Evaluation of the tire cross-section shape in relation with the traction force and traction efficiency of an agricultural tire

pg(s) 64-67

In this paper the traction force and traction efficiency of an agricultural type tire were evaluated, using a semi-empirical traction model of the driving wheel of a Romanian tractor; the model is based on Bekker’s pressure-sinkage relationship and on the ASAE equations for traction force and traction efficiency.
Tire deformation under vertical load was taken into account by the means of tire volume stiffness; three variants were considered in terms of tire cross-section: elliptical shape, spherical segment shape and toroidal shape.
Experimental data, obtained when ploughing operations were performed, were used in order to validate the results predicted by the models, using goodness-of-fit analysis.
It was concluded that the model based on the spherical segment shape of the tire cross section provided acceptable results for both traction force and traction efficiency in comparison with the experimental values; the other two models were more accurate in relation with the traction force, but proved to be less precise when referring to traction efficiency.

• ## Study of the influence of the irrigation regime on the yield of short-fruited cucumbers grown in open areas under drip irrigation

pg(s) 68-70

In order to establish the irrigation regime of short-fruited cucumbers in open areas in the soil-meteorological conditions of the area of the village of Chelopechene – Sofia, researches were carried out in drip irrigation of cucumbers variety “Levina”, testing different regimes – from full satisfaction of daily needs the culture from water to irrigation with reduction by 30% of the irrigation norm. A variant with a 30% increase in the irrigation rate was also tested.
The obtained results show that the cultivation of short-fruited cucumbers for fresh consumption in open areas requires 15 waterings with an average irrigation rate of 18.3 mm, which is realized at different intervals depending on plant development and the stress of metrological factors and irrigation rate 280 mm.
The realized irrigation regimes have influenced the formation of yields of short-fruited cucumbers. The yields during the three years of the experiment varied from 2368 to 5404 kg / dka, with the highest yields being obtained in the first and second years. Yields in the third year were lower by 30% as a result of adverse weather conditions, which led to a shortening of the growing season of the crop.

• ## Energy consumption and emissions of agricultural machinery for different arable land types

pg(s) 71-74

In this research, a survey was conducted in the Republic of Croatia in order to determine energy consumption in agriculture. The survey included collecting data on agricultural machinery based on machine type, fuel used, type of business and arable land type. There were more than 9,000 participants in the survey, of which more than 6,000 family farms. Results are shown on a national level for four land types: arable land, meadows and pastures, olive plantations and vineyards, as well as for three groups of participants: enterprises, family farms, and eco-producers. The last was found to have the lowest energy consumption and emissions on most land types, except on arable land, where all three groups have similar results. Vineyards had the highest emissions per hectare, while meadows and pastures had the lowest.

• ## Balkan endemic plants of Shutman Strict Nature Reserve in Kosovo – an inventory with chorological and life-form analyses

pg(s) 75-78

Balkan endemic taxa are those whose distribution is restricted exclusively to the Balkan Peninsula. The aim of the present study is to determine the number of the Balkan endemic taxa in Shutman Strict Nature Reserve in Kosovo and to presented chorological groups and life-form categories of this flora. In the investigated area are recorded 67 Balkan endemic and sub-endemic species and subspecies. The most important contributors at family rank in the Balkan endemic taxa are Asteraceae, Caryophyllaceae, Brassicaceae, Campanulaceae and Rosaceae, while the richest genuses are Silene, Achillea and Campanula. In the chorological structure of the of the Balkan endemics the
largest numbers are from the Balkan, S European and C European chorological groups, while in the life-form spectrum of the flora hemicryptophytes and chamaephytes are the most abundant. The data of the study showed that Reserve of Shutman has a very high level of endemic species. This fact shows that Shutman Reserve is an important center of the Balkan endemic flora in the Kosovo and the Balkan Peninsula and the existence of a rich endemic flora is of great importance in the conservation of biodiversity in this area.