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A consideration of phenanthrene presence in Bor's municipality based on its content in leaves and stems of Hedera helix L.
(Union of Mechanical and Electrotechnical Engineers and Technicians of Serbia (SMEITS), 2023) Papludis, Aleksandra; Alagić, Slađana; Milić, Snežana; Nikolić, Jelena; Medić, Dragana; Stević, Zoran; Stankov Jovanović, Vesna
In this work, unwashed samples of leaves and stems of poison ivy, Hedera helix (Hh), which grows naturally in the area of the town of Bor and its surroundings, were analyzed for the content of phenanthrene (Phe), as a dangerous pollutant belonging to the group of polycyclic aromatic hydrocarbons (PAHs). The concentrations of Phe at all investigated sites were significantly higher in leaves than in stems: 1084.28 μg/kg and 675.08 μg/kg, respectively. The highest concentrations in the leaves were detected at the sites: BN (107.42 μg/kg), SN (190.15 μg/kg), O (220.82 μg/kg) and NS (265.03 μg/kg). Based on the calculated factor R and Pearson's correlation coefficients, it is turned out that the sources of Phe for leaves and stems in Hh from the municipality of Bor were numerous - in addition to the emissions from the mining and metallurgical complex (with the smelting and city heating plant, as the main sources of pollution), the other sources are most likely: the domestic heating and traffic. Finally, Phe (as one of the low-molecular weight PAHs) may come in the investigated plant parts not only from the atmosphere but also from the soil.
A note on additive formulas for the Drazin inverse of matrices and block representations
(University of Niš, Faculty of Sciences and Mathematics, 2024) Ilić, Ivana; Stanišev, Ivana; Višnjić, Jelena
In this paper, we investigate the additive properties of the Drazin inverse for complex matrices. We derive new additive formulas for the Drazin inverse, which generalize some previous results on the subject. Furthermore, we give a new representation for the Drazin inverse of a block matrix, which extends some known representations.
A novel approach to copper leaching from chalcopyrite with sulphuric acid solutions
(Association of Metallurgical Engineers of Serbia (AMES), 2023) Bogdanović, Grozdanka; Petrović, Sanja
Chalcopyrite is the most abundant copper sulphide mineral. Extensive research in the field of hydrometallurgy was conducted with the aim of developing efficient processes for leaching copper from chalcopyrite concentrates and lowgrade ores and/or complex chalcopyrite-containing ores. Chalcopyrite leaching in sulphuric acid solution was most studied with Fe (III) ions as an oxidant, with or without the assistance of microorganisms due to the simplicity and low cost of the process. In recent years, there has been increased interest in the possible use of different oxidizing reagents (hydrogen peroxide, ozone, chromium (VI) ions, etc.) for chalcopyrite leaching, with research being conducted at the laboratory level, probably due to their higher cost. The addition of organic compounds, such as alcohols (methanol, ethanol, ethylene glycol, isopropanol), in the acidic aqueous solution of hydrogen peroxide and sulfuric acid, had increased chalcopyrite leaching. The aim of this paper is to present a brief overview of the oxidative leaching of chalcopyrite by means of hydrogen peroxide in sulphuric acid solutions and with the presence of alcohols.
A renewable energy sources and sustainable development equation
(University of Belgrade, Technical Faculty in Bor, 2023) Nedeljković, Milan; Mladenović, Srba; Petrović, Jasmina
Natural resources are an essential part of our planet, providing us with everything from food and medicine to energy and building materials. Oil, metals, ores, minerals, plants and animals, water, air, land, etc. are all examples of natural resources. A nation's wealth, status in the world economy, power, and political influence are determined by its natural resources. Natural resources are a universal good and a common resource. Their use, economic implementation and economic exploitation should be committed and well planned. Human activities such as overconsumption, pollution, and deforestation are placing increasing stress on these resources. To ensure that we can continue to rely on them in the future, we must use natural resources according to the principles of sustainable development. The process of meeting the needs of the present without compromising the ability of future generations to meet their own needs is called sustainable development. It involves striking a balance between economic growth and the protection of the environment and the conservation of biodiversity. By sustainably conserving natural resources, we can reduce the impact of climate change and ensure that ecosystems continue to perform important functions such as pollination, carbon sequestration, and air and water purification.
A short review of application the UAV remote sensing technology in the surface coal mine reclamation
(Mining and Metallurgy Institute Bor, 2024) Ilić, Aleksandra; Sokolović, Jovica; Nikolić, Vladimir
The mining industry supplies the other industries with essential raw materials, thus enabling the stable national economy. Coal mining causes a land degradation and destruction of natural habitats. Reclamation phase is necessary for keeping the balance between the mining and nature. In order to maintain competitiveness in the market, the mining companies should embrace the innovative technologies of data acquisition and site inspection. In this study, a method of the Unmanned Aerial Vehicle (UAV) remote sensing for accomplishing the high-accurate topographic surveys is proposed. A review of positive practices in the world that support the idea of sustainable and inventive approaches towards the mine reclamation will be given.
A simple method of determining of Bond work index for finer samples
(University of Belgrade, Technical Faculty in Bor, 2023) Nikolić, Vladimir; Trumić, Milan
The Bond’s method is based on the experimental determination of the Bond work index which represents a measure of ore resistance to grinding and its denotation is W_i. The conditions for performing the test and initial sample size are precisely defined within Bond’s standard test. The procedure for the determination of the Bond work index for finer samples was presented in this paper. These finer samples are usually seen as a problem for practitioners who work on the design and optimization of a plant.
A Simple Procedure for Evaluating the Economic Justification of Replacing Electromechanical Relay Protection in Power Plants with Microprocessor Protection
(The Institute of Electrical and Electronics Engineers (IEEE), 2024) Perović, Bojan; Milovanović, Miloš; Vukašinović, Jovan; Jovanović, Andrijana; Gajić, Milena; Vulović, Marko
This paper describes the procedure for evaluating the economic feasibility of replacing electromechanical relay protection in power plants with microprocessor protection. The procedure is applied on the example of the “Gazivode” hydroelectric power plant (HPP), where it was shown that the entire investment can be repaid in about 2.5 years. This can be achieved based on the reduction of costs of operation and maintenance, overhaul and unsupplied electricity for the case of microprocessor protection compared to the case of electromechanical protection.
About the “relative plasticity” between steel matrix and non-metallic inclusions
(University of Belgrade, Technical Faculty in Bor, 2023) Karastojković, Zoran; Gusković, Dragoslav; Ristić, Ognjen; Kovačević, Zorica
It is clearly established in metallurgy, also in service of machine elements or components, that non-metallic inclusions are not desired into metals, either they are ferrous or nonferrous. One of the main factor for such conclusion is in markably decreasing the plasticity with increasing an amount of the non-metallic contenst. Non-metallic inclusions were classified according to its nature, shape and dimensions, as many national standards were defined those properties. Sometimes is not simple to make a fully definition of the plasticity, as a property important both for cold or hot deformation processes, because many factors must be involved at the same time. One attempt for judging the plasticity of a steel was made by using a “relatively plasticity”.
Academic ethics as seen by students – The Central-European case
(University of Belgrade, Technical Faculty in Bor, 2023) Piricz, Noémi; Voza, Danijela
The intensive ethical dilemmas characterize the contemporary world, so ethics as a scientific discipline is even more present in the scientific world and the educational system. Numerous universities offer their students the opportunity to study ethics as a scientific field. That enables young people to become more familiar with her and the application of her theories in everyday decision-making. At the faculties of business and management, business ethics is receiving more and more attention after numerous scandals, the center of which were the most famous multinational companies. In addition to family, friends, and national culture, education is important in creating, adopting, and disseminating ethics. Higher education institutions should not be singled out in this, even though, as a rule, they do not deal with an educational role. Professors should be a model for creating morally responsible future generations. This research aimed to determine students' perception of ethical issues in the University environment. The authors examined how demographic characteristics influence their ethical attitudes and tried to define the ethical dimensions in their perception of the faculty's role in the individual's ethics. In order to achieve this goal, a survey was conducted among students from Hungary and Serbia. ANOVA and factor analysis processed the obtained data set. The results indicate that students consider the faculty an important factor in shaping individual ethics. Conversely, students are sometimes held to different ethical standards than other constituents.
Adsorption isotherms for copper ions adsorption onto walnut shells
(University of Belgrade, Technical Faculty in Bor, 2021) Gorgievski, Milan; Marković, Miljan; Božić, Dragana; Stanković, Velizar; Štrbac, Nada; Grekulović, Vesna; Zdravković, Milica
In this paper Langmuir, Freundlich, and Temkin adsorption isotherm models were used for describing the adsorption of copper ions onto walnut shells. The adsorption was performed in a batch system. The obtained isotherm data were fitted using the mentioned models, and the isotherm parameters were calculated from the linearized plots corresponding to each model. The Langmuir adsorption isotherm model showed the best agreement with the analyzed experimental data, with the correlation coefficient R2 = 0.993. According to this model, the adsorption process occurs until a complete monolayer of copper ions is formed on the surface of the walnut shells. The maximum adsorption capacity, according to this model, was 7.71 mg g-1.
Adsorption isotherms for copper ions biosorption onto onion peels
(University of Belgrade, Technical Faculty in Bor, 2023) Gorgievski, Milan; Marković, Miljan; Štrbac, Nada; Grekulović, Vesna; Zdravković, Milica
Langmuir, Freundlich, and Temkin isotherm models were used to study the equilibrium and mechanism of biosorption of copper ions onto onion peels under batch conditions. Isotherm parameters were calculated from the line graphs according to each model. The results obtained on the basis of correlation coefficients, show that the Freundlich isotherm model (R2 = 0.964) is in good agreement with the analyzed experimental data. This model assumes that the surface energy of the adsorbent is heterogeneous, strong binding sites are occupied first, and that the binding energy decreases as the number of occupied adsorbent sites increases.
Adsorption isotherms for copper ions biosorption onto walnut shells
(University of Belgrade, Technical Faculty in Bor, 2022) Marković, Miljan; Gorgievski, Milan; Štrbac, Nada; Božinović, Kristina; Grekulović, Vesna; Mitovski, Aleksandra; Zdravković, Milica
Equilibrium analysis of copper ions biosorption onto walnut shells is presented in this paper. The experimental data were analyzed using three isotherm models, namely, the Langmuir adsorption isotherm model, the Freundlich adsorption isotherm model, and the Temkin adsorption isotherm model. Obtained results indicate that the Langmuir model fits best the experimental data (R2 = 0.993), indicating that the biosorption of copper ions occurs in a monolayer. The small difference between qe,exp and qe,m point to that the walnut shells are almost completely saturated with copper ions.
Adsorption kinetics for copper ions adsorption onto onion peels
(University of Belgrade, Technical Faculty in Bor, 2023) Gorgievski, Milan; Marković, Miljan; Štrbac, Nada; Grekulović, Vesna; Božinović, Kristina; Zdravković, Milica; Marković, Marina
Kinetic analysis of copper ions adsorption onto onion peels is presented in this paper. The experimental kinetic data were analyzed using two kinetic models, namely the pseudo-first order kinetic model and the pseudo-second order kinetic model. The kinetic parameters were calculated from the linearized plots of the corresponding models. The obtained results indicate that the adsorption of copper ions onto onion peels follows the pseudo second-order kinetic model, with a correlation coefficient of R2 = 0.994. This indicates that the chemical interaction between the surface functional groups is the limiting factor of the process rate.
Advantages of mining engineering curriculum realization using solutions based on free software
(University of Belgrade, Technical Faculty in Bor, 2021) Stolić, Predrag; Ivaz, Jelena; Petrović, Dejan; Stević, Zoran
Higher education institutions mainly use commercial software in the realization of their teaching process. The transition to the online teaching process revealed certain problems when using this type of software and it was necessary to find an adequate solution to overcome the problems related to online teaching environment. Certainly one of the solutions is to find appropriate software alternatives that are free from certain restrictions which are manifested during commercial software use. The paper shows how these problems are practically overcome by introducing free and open source software within the implementation of the teaching process in two subjects of the study program Mining Engineering at the Technical Faculty in Bor. The specific reasons and proper analysis for making such a transition are presented, as well as the analysis of the results achieved during the previous academic years when the mentioned software is used in a real environment during the teaching process.
Air pollution in the Bor region from 1994 to 2023
(University of Belgrade, Technical Faculty in Bor, 2024) Šerbula, Snežana; Kalinović, Tanja; Kalinović, Jelena; Radojević, Ana; Jordanović, Jelena
This study considered the historical air pollution data. Assessment of air quality in Bor was done for the period 1994–2023, namely since the installation of monitoring stations for measuring the concentrations of most common air pollutants such as SO2, PM10 and toxic elements As, Cd and Pb in PM10 samples, at several different locations in relation to the location of the copper smelter. Modernizations of the Flash smelting technology were carried out in 2015 and 2022, which partially affected the reduction of air pollution. The measured concentrations of SO2, PM10, As in PM10 as well Pb and Cd indicated frequent exceedances of defined annual limit values, both at the national and European levels. The maximum average annual SO2 concentration reached 372 μg/m3 in 2012 and was 7.5 times higher than the legally prescribed values. Air quality regarding the levels of PM10 and especially As in PM10 was significantly worse after modernization. The annual concentration of As exceeded the annual target velue defined by the European and Serbian regulations, at all monitoring sites, with a maximum exceedance of more than 90 times at the suburban location during 2019. Frequent exceedances of the respective annual target values were also noted for Pb and Cd in PM10 samples. The analyzed data pointed out that the Bor region can still be characterized as an ecological hotspot in Serbia and beyond.
An investigation into foreign language anxiety (FLA) among students at the Technical Faculty in Bor
(University of Belgrade, Faculty of Philology, 2020) Stevanović, Slavica; Vasković, Sandra
Despite the fact that foreign language anxiety (FLA) has attracted much interest over the last thirty years and that FLA has also been recognized and documented as one of the factors affecting learner performance, this aspect of EFL has been disregarded in Serbia, and there are no studies that we are aware of concerning this phenomenon. This paper is aimed at presenting findings on FLA of 101 first-year students of the Technical Faculty in Bor, Serbia, and contributing to the existing literature on FLA, as well as at confirming the reliability of Foreign Language Anxiety Scale (FCLAS) as an instrument to measure potential anxiety in EFL classroom. The theoretical objective of this study was to examine Horwitz et al.’s model of FCLAS as well as to produce an adapted version of FCLAS suitable for Serbian learners’ attitude towards FLA. The adapted version of FCLAS was administered to 101 non-major English students of the Technical Faculty in Bor, and the findings are presented in this paper.
Analysis of business processes in railways and public enterprises of Serbia
(University of Belgrade, Technical faculty in Bor, 2024) Marković, Filip; Urošević, Snežana
Managing an organization of any kind and achieving its goals, especially in terms of increasing effectiveness, efficiency and realization of set goals and strategies, requires a thorough understanding of its internal functioning and structure. It is crucial to understand that the organization's activities are realized through a series of connected and goal-oriented business processes. Through the review of the conceptual definition of business processes and the consideration of models for their analysis, the specifics of the application of these processes in the context of the railway and the public sector in the Republic of Serbia are explored. The current context of research in the field of business processes in Serbia is analyzed, with a focus on the characteristics of the railway and public sectors.
Analysis of innovation in EU countries
(University of Belgrade, Technical Faculty in Bor, 2024) Nikolić, Ivica; Stojanović, Anđelka; Radić, Aleksandra; Đorđević, Predrag
This paper explores the level of innovativeness among European Union (EU) countries through the application of the Global Innovation Index (GII) and cluster analysis methodology. The research aims to identify the key factors contributing to innovation in various EU countries and to group these countries into homogeneous cluster groups to understand their innovation performance better. Cluster analysis is employed to identify similarities among countries based on their innovation characteristics. The research results provide insight into the relative position of EU countries in the domain of innovation, identifying innovation leaders as well as those lagging behind. Cluster analysis enables the grouping of countries into cluster groups based on similarities in their innovation profiles, facilitating the identification of common challenges and opportunities for collaboration.
Analysis of safety climate factors in textile industry
(Union of Engineers and Textile Technicians of Serbia, Belgrade, 2024) Milijić, Nenad; Stefanović, Violeta
This paper presents the results of the analysis of the impact of the main safety climate elements on the overall occupational safety in textile companies in the Republic of Serbia. SEM (Structural Equation Modeling) methodology was applied to validate and test the proposed conceptual model of safety climate. A statistical analysis was performed using the software package SPSS 18.0 and Smart PLS 4. The previously developed model with seven hypotheses was tested on a sample of 267 respondents employed in 8 companies. The results of the empirical research confirm some of the hypotheses and point to the existence of a positive correlation between them. Within the conclusions of the research, special emphasis is placed on those safety climate factors where certain possibilities for improvement have been established and which represent the specificity of textile industry. Finally, the obtained results point to the significant fact that the formation of an adequate safety climate in textile companies can have a positive effect on the improvement of overall occupational safety in this sector.
Analysis of the effectiveness of different methods for cutting samples
(University of Belgrade, Technical Faculty in Bor, 2023) Štirbanović, Zoran; Vojinović, Vesna; Sokolović, Jovica; Trumić, Maja
In this paper are presented the results of analysis of effectiveness of four different sample cutting methods: quartering, "chessboard" method, Jones riffle splitter and automatic sampler “Vezin”. For the analysis of their performance four copper ore samples with different grain size were used. Grain size composition of samples before and after cutting was determined and used for calculating absolute average deviation and real average deviation which were used for determining effectiveness of used methods. According to the obtained results "chessboard" method was the most efficient for cutting all investigated samples, i.e. it provided the samples with highest representativeness.

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