Faculty of Mechanical Engineering

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ВЕКТОРИТЕ ВО ОСНОВНОТО ОБРАЗОВАНИЕ, ПРЕД И ПОСЛЕ ВОВЕДУВАЊЕТО НА КЕМБРИЏ ПРОГРАМАТА
(Union od Mathematicians of Macedonia – ARMAGANKA, 2020)
Dimovska, Ana
;
Во оваа статија е направена споредба на старата програма по математика и Кембриџ програмата од аспект на вектори. Ставен е акцент на потребата од изучување на векторите во основното образование. Моти- вацијата за оваа статија, односно користењето на “векторскиот” пристап е развивање на геометриска интуиција за концептите како права, рамнина и простор; полесна интерпретација на проблеми од геометрија и навремено совладување на техника која е корисна од чисто математички цели (ко- рисна во други математички области), но и во интердисциплинарни об- ласти како физика, хемија, компјутерски науки и други. Потребата од изучувањето на вектори во оваа статија е заокружена со елементарни при- мери од геометрија и физика.
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ПИСА ТЕСТИРАЊЕТО ВО СРЕДНИТЕ СТРУЧНИ УЧИЛИШТА
(Union od Mathematicians of Macedonia – ARMAGANKA, 2022)
Dimovska, Ana
;
Во оваа статија правиме детална анализа на ПИСА тестирања во други земји и правиме компарација со ПИСА тестирање спроведено во средно стручно училиште во нашата земја. Добиваме резултати за квалитетот на образовниот процес со и без соодветна подготовка за овој вид тестирање, како и разбирање на математиката воопшто.
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Cantor’s Intersection Theorem in (3,1,∇)-G-metrizable spaces
(Union od Mathematicians of Macedonia – ARMAGANKA, 2022)
Dimovski, Tomi
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Dimovski, Pavel
In this article we prove some properties of (3, 1,∇)-G-metrizable spaces and establish analogous Cantor’s intersection theorem for those kinds of spaces.
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Repurposed EV batteries integration in smart energy grids to facilitate a greener energy sector
(Information Society of Serbia - ISOS, 2022)
Dimitrovski, D., Manev, N., Jovanovikj, E., & Uler-Zefikj, M.
The global fleet of electric and hybrid vehicles (EVs) is predicted to grow immensely over the next decade, leading to lower CO2 emissions in road transportation but higher demand for lithium-ion batteries. Battery manufacturing and even battery recycling are both very carbon and energy-intensive processes. Having environmental sustainability in mind, reusing is the preferable technique to the production of waste and recycling since it provides an opportunity to extend the EVs batteries’ lifespan by reusing them in different second-life applications. Reusing batteries in battery energy storage systems (BESS) complements the idea of a smart grid by allowing energy storage at periods of low demand at night and release during the grid peaks, grid frequency regulation and levelling peaks in renewable energy generation, thereby alleviating the intermittent nature of renewable energy sources and decreasing the carbon footprint of the energy sector. The aim of this paper is to conduct an analysis on the benefits of reusing and repurposing EV batteries in smart BESS compared to direct recycling by using available data and case studies. A careful review of the materials shows that the benefits outweigh the disadvantages of repurposing vehicle batteries into secondary applications considering the carbon-intensiveness of the battery recycling process. The benefits of using repurposed battery packs have a major potential to facilitate a greener energy sector by shifting electricity purchases to off-peak times, more efficient use of the energy grid by providing constant energy reserves and storage for meeting changes in supply and demand, emission reductions, integration of renewable power and supporting their expansion, as well as more effective use of original materials.
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General overview of the operation, efficiency, and emissions of waste-to-energy technologies
(Faculty of Mechanical Engineering in Niš, 2022)
Uler-Zefikj, M., Shesho, I., Filkoski, R., Tashevski, D., & Dimitrovski, D.
The amount of waste generated in the Western Balkans region has been steadily increasing throughout the years, with a current amount of 1000 kg generated waste per capita with a recycling rate below 3%. This brings the necessity to analyse different types of waste regarding their calorific value, particle size and moisture content to determine the capacity to use them as low-cost renewable fuels in waste-to-energy (WtE) facilities. By studying the mode and conditions of operation, and process efficiency of different WtE conversion technologies, the suitability of each technique for generating electricity, heat or fuel can be defined. The WtE technology market is presented by providing specific examples of real plants installed around the world, accenting the advantages and shortcomings of each case. Results obtained from the literature review performed show that WtE processes encourage a circular economy by transforming waste management into a resource management system. Finally, WtE contributes to the reduction of landfill waste by its exploitation for renewable energy generation representing a sustainable process. However, some limiting factors remain to be surpassed for these techniques to pair up with conventional energy systems.
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Assessment of the potential for increasing the renewable energy share into district heating system by integration of decentralized solar assisted heating systems
(Savez energetičara, 2021)
Shesho, I., Filkoski, R., Tashevski, D., & Uler-Zefik, M.
The decrease in conventional energy resources, environmental pollution issues and climate change are the leading factors inducing the increase of energy efficiency criteria’s. Trends to improve energy efficiency are mainly aimed at the construction sector as one of the leading sectors in energy consumption. In the paper are analyzed the performance of the decentralized solar assisted heating systems (SAHS) for climatic conditions in Macedonia in order to assess the possibility to be integrated as part of the district heating system. The analysis is based on a holistic approach, in which the performance of the SAHS are generally functionally dependent on four factors: (1) the characteristics of each component, (2) the system structure and mutual interactions of the components, (3) the management method and (4) specific energy consumption for heating of the building. The specific analysis is directed toward assessment of the solar fraction of the SAHS as a function of the building energy performance and system heating temperature range. The numerical modeling of the processes occurring in systems is performed with the dynamic simulation software TRNSYS. It is developed dynamic model of the solar combisystem and reference building. The dynamic model contributes in the flexibility of conducting parametric analysis. The obtained results from the parametric analysis are condensed in a general table upon which was performed analysis of system performance.
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Implementing Model Predictive Control (MPC) in Steer-by-Wire Systems for Future Automated Vehicles
(IOP Publishing, 2024-09-01)
Changoski, Vasko
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Vasileva, Anita
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Jakimovska, Kristina
;
The need for future green sustainable transportation represents a motivation for the researchers in order to create a better society. In this paper a proposed Steer-by-Wire system for future automated vehicles is analysed by implementing model predictive control (MPC) controller that would optimise the desired behaviour of the vehicle. By using MATLAB/Simulink, a bicycle vehicle model is simulated in standardised test manoeuvres according to standard ISO:7401. These results are used as referent data for the desired trajectory of the vehicle and as input data for the MPC controller. The idea of using these results for the controller is generated by the desire of creating a shared information intelligent systems. Shared information and control in the future intelligent systems would be crucial for creating the desired sustainable transport. By traveling, the vehicle would collect data of the desired measured variables and those data would be send to every other vehicle. Therefore, the next vehicle would possess the previous data and would try to improve the vehicle response and safety. Every optimised trajectory would be shared with the rest of the vehicles and this cycle would result in further optimization and in creation of a safer, more comfortable and more sustainable transport. The optimisation is done by the MPC controller which is responsible for defining the steering wheel angle and therefore creating the Steer-by-Wire system that is entirely defined by the MPC controller without driver commands. By comparing the trajectory of the automated vehicle and the desired trajectory gained from the previous simulations, the desired steering wheel angle is defined. This results in creation of a Steer-by-Wire system that improves the vehicle dynamics, safety and dynamic response of the vehicle. The mathematical modelling, results of the simulations and advantages of using the MPC controller for the Steer-by-Wire system in automated vehicle are presented.
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Improving vehicle dynamics employing individual and coordinated sliding mode control in vehicle stability, active front wheel steering and active rear wheel steering systems in co-simulation environment
(IOP Publishing, 2022-12-01)
Changoski, Vasko
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Gjurkov, Igor
;
The goal for the future, safer and more sustainable transportation leads to implementation of many advanced systems in vehicles. In this paper, a vehicle model with stability control system that uses the braking system is regarded as a base active vehicle. Two alternative vehicle models are considered where this system is combined and integrated with active front wheel steering (AFS) and active rear wheel steering (ARS) system, separately. For the purpose of this research, 3D virtual vehicle models based on a B-segment vehicle were created in ADAMS/Car. As a research tool, a co-simulation approach between ADAMS/Car and MATLAB/Simulink was used. Several sliding mode controllers (SMC) have been proposed and implemented in MATLAB/Simulink in order to analyse the potential improvements of the vehicle dynamics due to the integration and coordination of these systems. In the same MATLAB/Simulink environment, a reference 2DOF nonlinear bicycle model was used. The vehicle models were simulated in driving scenarios based on standardized ISO 7401 test procedures. The scenarios include situations where the passive vehicle loses its stability or fails to complete the manoeuvre while the vehicles with stability control or integrated control systems successfully complete it.
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Implementing Model Predictive Control (MPC) in Steer-by-Wire Systems for Future Automated Vehicles
(IOP Publishing, 2024-09-01)
Changoski, V
;
Vasileva, A
;
Jakimovska, K
;
Danev, D
The need for future green sustainable transportation represents a motivation for the researchers in order to create a better society. In this paper a proposed Steer-by-Wire system for future automated vehicles is analysed by implementing model predictive control (MPC) controller that would optimise the desired behaviour of the vehicle. By using MATLAB/Simulink, a bicycle vehicle model is simulated in standardised test manoeuvres according to standard ISO:7401. These results are used as referent data for the desired trajectory of the vehicle and as input data for the MPC controller. The idea of using these results for the controller is generated by the desire of creating a shared information intelligent systems. Shared information and control in the future intelligent systems would be crucial for creating the desired sustainable transport. By traveling, the vehicle would collect data of the desired measured variables and those data would be send to every other vehicle. Therefore, the next vehicle would possess the previous data and would try to improve the vehicle response and safety. Every optimised trajectory would be shared with the rest of the vehicles and this cycle would result in further optimization and in creation of a safer, more comfortable and more sustainable transport. The optimisation is done by the MPC controller which is responsible for defining the steering wheel angle and therefore creating the Steer-by-Wire system that is entirely defined by the MPC controller without driver commands. By comparing the trajectory of the automated vehicle and the desired trajectory gained from the previous simulations, the desired steering wheel angle is defined. This results in creation of a Steer-by-Wire system that improves the vehicle dynamics, safety and dynamic response of the vehicle. The mathematical modelling, results of the simulations and advantages of using the MPC controller for the Steer-by-Wire system in automated vehicle are presented.
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Influence of Edge Surface Quality on Hybrid Laser Arc Welding of Structural Steel S355J2
(2024)
Petreski, Martin
;
;
Vrtanoski, Gligorche
;
Krstevska, Aleksandra

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