NIR

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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 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 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.
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.
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 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.
Analysis of the project-based organizations' characteristics influence on project management performance
(University of Belgrade, Technical Faculty in Bor, 2023) Milijić, Nenad; Jovanović, Ivan; Radić, Aleksandra
This paper presents the empirical results of the analysis of the project-based organizations' characteristics influence on project management performance, that is, on the effectiveness of project goals achieving. As a basis, it was used a multidimensional approach to project success assessment, through project management performance analysis, which emphasizes meeting the expectations of all stakeholders. The broader approach was chosen as a more comprehensive way of solving problems in the project environment in the current crisis and changing circumstances. The research was conducted in 11 project-based organizations operating in various industrial sectors on the territory of the Republic of Serbia. A total of 253 employees were surveyed (project managers, production workers, and workers indirectly related to production). Statistical analysis of collected data was performed using the SPSS 18.0 software package. The mentioned impact was tested using the Multivariate analysis of variance (MANOVA) and it was found that project-based organizations' characteristics have a significant influence on project management performance.
Analysis of the thermal properties of particle-reinforced aluminum composites
(Fakultet Tehničkih nauka, Kosovska Mitrovica, 2023) Petrović, Jasmina; Mladenović, Srba; Marković, Ivana; Stamenković, Uroš; Nedeljković, Milan; Mitrović, Milijana
In recent years, there has been a lot of interest in aluminum composites because of their improved mechanical properties, higher thermal stability, and lower weight than standard aluminum alloys. The thermal behavior of aluminum composites was examined during continuous heating, and thermal diffusivity and conductivity were measured. The experimental procedure involved the reinforcement of the aluminum matrix AN EW 6061 with ceramic particles Al2O3 to create aluminum composites. The reinforcer was used in size 80 um and three different fractions of 2 mas%, 5 mas% and 8 mas%. Stir casting was used to produce the composite. The thermal characteristics of solidified composite samples were measured using the flash method during continuous heating in a protected nitrogen environment at a heating rate of 10 °C/min. The thermal diffusivity and thermal conductivity values were found to be slightly lower compared to the matrix alloy. In addition, as the mass fraction of reinforcement in the composite increased, the thermal diffusivity values decreased, while the thermal conductivity values first decreased and then increased.
Analysis of the Western Balkans countries' innovative systems
(University of Belgrade, Technical Faculty in Bor, 2023) Fedajev, Aleksandra; Panić, Marija; Živkovic, Živan
While the Western Balkan (WB) countries have been actively seeking membership in the EU, their level of development is diverging more and more from that of the EU as a whole. Along with the protracted reform processes and numerous political and social unrest, these nations' lack of innovation should be considered a possible cause of these results. Based on information from the GII report for 2021, this research seeks to conduct a comparative analysis of the innovation in the WB countries and pinpoint their major advantages and disadvantages in this area. According to the results, Serbia is the top-ranked country when all factors are considered. The results have outlined some recommendations and instructions for economic policymakers in these countries to enhance innovation in the future.
Application of a simple pretreatment in the process of acid leaching of electric arc furnace dust
(MDPI, 2024) Trifunović, Vanja; Milić, Snežana; Avramović, Ljiljana; Bugarin, Mile; Đorđievski, Stefan; Antonijević, Milan; Radovanović, Milan
Experimental investigations of the effectiveness of the pretreatment of the acid leaching process of a representative sample of electric arc furnace dust (EAF dust) and characterization of a representative sample were performed. As EAF dust is globally defined as hazardous solid industrial waste, and it contains a high percentage of zinc and other useful components, in this paper, the application of pretreatment will be carried out in order to increase the efficiency of the further process of acid leaching, all with the aim of using EAF dust as a secondary raw material for metal valorization. The pretreatment involved the application of a simple process of leaching the EAF dust sample with distilled water. Under the following defined optimal leaching conditions: time—30 min, ratio of solid to liquid phase—1:10, temperature—ambient, and stirring speed—500 rpm, a reduction in the content of water-soluble components was achieved, namely, 83% Cl, 92% K, 74% Na, 14% Cd, 15% Ca, and 19% F. The application of the pretreatment enables significantly better filtration of the suspension and increases the leaching efficiency of zinc and other useful components in the further process of leaching EAF dust with a sulfuric acid solution, compared with the process of direct acid leaching of EAF dust.
Application of green areas and green roofs in urban areas
(University of Belgrade, Technical Faculty in Bor, 2022) Stojić, Anđela; Tanikić, Dejan
Modern city development a large number of cars and industrial plants have led to a dramatic decline in air quality, which in some cities around the world reaches alarming parameters, which are very harmful to public health. In larger cities, during most of the year, air quality is in a moderately harmful and harmful range. Modern urban development, which introduces various new materials and sources of pollution into the urban fabric, should require an increase in the percentage of green areas, in order to maintain air quality at a level estimated to be healthy for human life. Strategic afforestation of parts of cities could have the effect of reducing the amount of harmful particles in the air, planting tall plants would in some way lead to the filtration of city air. The construction of green, vegetation, roofs would mitigate the effect of the heat island, reduce the energy needed to cool buildings, effectively manage atmospheric water, improve air quality, increase biodiversity, reduce noise, etc.
Application of the circular economy concept in construction and architecture
(University Ss. Cyril and Methodius in Skopje, Faculty of Technology and Metallurgy, Skopje, North Macedonia, 2024) Urošević, Snežana; Urošević, Igor
Applying the concept of circular economy and adhering to circular economy guidelines is a lot more than reducing or recycling waste. By using recycled material, i.e. reusing materials reduces the use of natural resources and the generation of waste. The paper describes the acceptance of the idea of a circular economy in construction, which reduces the total use of resources during the lifetime of buildings. It is about fundamentally rethinking the way buildings are designed, built, and used, allowing for a longer building life, where a return to processes such as depreciation and demolition is avoided. As the global population has doubled since 1970, resource use has tripled to meet demand, which continues to grow. This demand is best seen in the construction industry, which with increasing urbanization and rapid development of cities, leaves a huge mark on the natural environment. It is estimated that the circular economy in construction, by moving to a completely zero-emission regime, could significantly reduce the global CO2 emissions that this industry leaves behind. The transition to a circular economy is accompanied by the saving of resources, the reuse of the built environment, as well as the creation of new specializations and new jobs. Careful management of materials and resources would enable greater savings in the production chain, lower fuel consumption, lower CO2 emissions, less construction waste, and a healthier and cleaner natural environment for everyone.

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