Table of Contents


    • Mathematical modeling of features of electrophysical processes in a vibration plow with piezoelectric actuator

      pg(s) 3-6

      In the process of studying multiphysical processes, including electrophysical ones, the resonance frequency at which the piezoelectric actuator maximally influences the amplitude of oscillations of the plow blade was established in the COMSOL Multiphysics software package. The maximum amplitude of oscillations of the plow-piezo actuator system and the rational location of the piezo actuator on the dump, which provides an efficient vibration process, have also been dete rmined. The performed numerical experiments allowed to obtain approximation expressions for simplified determination of the amplitude of oscillations of the system depending on the coordinates of the piezo actuator on the heap. The research results can be used in the design of vibrating soil cultivation bodies in agricultural machinery.

    • Research of combustion engine oil quality over exploitation period

      pg(s) 7-10

      Different types of oil are used widely in all over the world. It is used for lowering friction force at the contact zones, e. g., bearings, gears and other areas where at least one element is moving in relation to another one. Several types of oils find place in automotive industry: mineral, semi-synthetic and synthetic. Over the time oil characteristics were improved by enriching with different additives. Special additives can reduce friction forces, present better wash of abrasion products, extend oil life, etc.
      This article deals with the research of degradation of oil lubrication quality in vehicle combustion engine over the exploitation period.
      Quantity of contaminating particles in oil sample was determined by optical microscopy. Oil film strength test was performed with oil samples used after various exploitation periods.

    • Kinematic analysis of the slider-crank mechanism of an internal combustion (IC) engine using modern software

      pg(s) 11-17

      The subject of research in this paper is the kinematic analysis of the slider-crank mechanism of an internal combustion (IC) engine. The piston, connecting rod and crankshaft are the most important moving parts of an IC engine. The performance of IC engines largely depends on the design of the mentioned parts. Special attention should be paid to the kinematic analysis of the slider-crank mechanism, when constructing IC engines. Properly performed kinematic analysis is a prerequisite for the design of an efficient IC engine. Today, there are many software packages that make it much easier for engineers to perform fast and efficient kinematic analysis of machine assemblies. This paper presents the use of kinematic analysis software on the example of a slider-crank mechanism, an IC engine.

    • Identifying Photovoltaic Water Pumping (PVWP) Systems Opportunities in Albanian’s Agriculture Context.

      pg(s) 18-23

      A lot of economic analyses have been conducted in the last ten years to establish the most cost-effective solution for irrigation and evaluation of the project profitability. The benefits generated by the PVWP providing water by a submersible pump located inside a deep well have been highlighted for Divjaka region. The solar potential in the site is quite enough to be used to pump water from the deep well into the tank positioned at an effective altitude which can provide the water quantity and pressure by gravity. The study shows that installing a PVWP system represents the best technical and economic solution to drive a water pump that provides water for sprinkler irrigation. The economic benefits have been also addressed, evaluating the energy production and distribution throughout the year and the specific cost per m3 of water supplied (€/m3). Renewables are the key to enhance food and water security, drive agri-food productivity, leading to socioeconomic benefits in recovering from post-Covid-19. By combining our knowledge, data collected, surveys together can contribute to economic growth of our community-ensuring access to clean and affordable energy and raising the standard of living of rural and most vulnerable communities. In the area there are used two types of water pumping for irrigation purposes: Diesel driven water pumps and electricity powered water pumps. Both systems are very costly due to the high fuel cost and on the other hand self-investment to bring electricity from the national distribution lines are needed.

    • Study of the magnetic field of a magnetic treatment device for agricultural materials

      pg(s) 24-46

      The type of supply voltage of the coil to achieve maximum induction and uniformity of the magnetic field in the magnetic chamber, where the processed material is determinate. The experimentally obtained dependence curves B=f(U) can be used to optimize the regime parameters when processing various agricultural materials in a magnetic field.

    • An overview of agriculture sector in terms of fuel type and systems used for irrigation purposes. Case study: Divjaka region, Albania

      pg(s) 27-31

      In locations where electricity is not available and distribution lines are far away from the connection point, than other means are necessary to provide water for different applications especially in agriculture sector. Using a diesel pump to deliver water account economic and environmental problems. Fuel prices affect the overall costs of diesel-powered water pumping system thereby reducing the incomes from the sale of vegetables or other planted crops. In addition, the use of a diesel-powered water pump system can lead to considerable amount of CO2 released to the surrounding which cause global warming. A possible solution to these problems is using renewable energy source like solar power, which is environmentally friendly and available for free. This paper focus on the identification of sector energy consumption and the possibility of application of PVWP system in the agriculture sector. Several economic analyses have been conducted to establish the best cost-effective solution for irrigation in agriculture sector. The possible benefits generated by the PVWP system implementation for the selected region should be highlighted, as well as the effects of the most sensitive parameters. The solar potential in the site showed that PVWP can be the best solution to provide water for irrigation compared to other traditional water pumping technologies and also can reduce the dependency from fossil fuel powered water pumps and can help the diversification of the agriculture sector especially.

    • Investigation of the movement of a tomato plant during the transition between transport devices

      pg(s) 32-34

      Mechanized harvesting of tomatoes should be carried out with minimal damage. This is achieved by knowing the processes. The movement of a tomato plant in the period of transition between conveying devices has been studied. Dependencies determining the length of free movement and the rates of fall on the fruit separator are derived, which are essential for determining the kinematic regime and preventing damage to the fruit.


    • Studies to establish the evapotranspiration of strawberries grown in open areas

      pg(s) 35-37

      Evapotranspiration of strawberry, remontant variety “Polka” (field production) was established in a three-year field experiment (2011-2013) drip irrigation on leached cinnamon forest soil in the area of the village of Chelopechene, Sofia region. Various irrigation regimes have been tested – from full satisfaction of the daily needs of the crop from water to irrigation with reduced by 20% and 40% irrigation rates.
      On average for the research period the size of the total evapotranspiration for the vegetation period of strawberry is 240 mm, as its main part is formed by the irrigation norm – 58%, and the rest of the precipitation – 42%. The average daily values vary by ten days, with the highest values reaching the first and second ten days of June (harvest period). Values of the biophysical coefficient Z necessary for determining the design irrigation regime and forecasting the time for irrigation of the crop have been determined.