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Milivojevic D.R.,Mining and Metallurgy Institute Bor | Tasic V.,Mining and Metallurgy Institute Bor | Pavlov M.,Mining and Metallurgy Institute Bor
Information Technology and Control | Year: 2010

Monitoring and control of technological processes in many production units demands transfer of information and interaction with the process from remote distances. For this purpose, the process control systems have been designed and developed. In the first project phase, the separate production lines were covered by independent control systems. In the second phase, the individual control systems were interconnected in a large heterogeneous industrial network, forming the distributed control system (DCS). This paper presents results of development of specific hardware and software solutions for monitoring of technological processes, with special regards to communication systems structure.

Gorgievski M.,Mining and Metallurgy Institute Bor | Bozic D.,Mining and Metallurgy Institute Bor | Stankovic V.,University of Belgrade | Strbac N.,University of Belgrade | Serbula S.,University of Belgrade
Ecological Engineering | Year: 2013

The adsorption of Cu2+, Zn2+ and Ni2+ ions from synthetic solutions was performed by using wheat straw. Physical and chemical characterization of wheat straw was done. The content of alkali and alkaline-earth metals, before and after rinsing of wheat straw with water, and after loading with Cu2+, Zn2+ and Ni2+ ions, was given. Chemical oxygen demand (COD) of rinsed water was determined prior to the adsorption experiments. The consumption of oxygen was 18mgdm-3. Besides the COD, the total cation exchange capacity (CEC) of alkali and alkaline-earth metals, exchanged in the reaction with NH4Cl, was also determined. The determined CEC of the wheat straw was 1.86mmol Mez+g-1. FTIR analysis of wheat straw, before and after adsorption of copper ions, revealed that hydroxyl functional groups were mainly responsible for the adsorption of Cu2+ ions. The point of zero charge (pHzpc) of wheat straw was experimentally found, being at pH=6.7.The kinetics of adsorption is described by a pseudo-second order reaction kinetic model, allowing the determination of kinetic parameters for each of the considered metal ions. The ion exchange mechanism was confirmed assuming that the alkali-earth metals (mostly calcium), from wheat straw, are substituted by the considered heavy metal ions and protons. For a single metal ion system, the adsorption equilibrium data can be modeled by the Langmuir adsorption isotherm for all considered ions. The maximum adsorption capacity of 5mgg-1 was achieved for copper ions, while the adsorption capacity for nickel and zinc ions was 2.5mgg-1 and 3.25mgg-1, respectively. The obtained results show that wheat straw can be successfully used as an adsorbent for the adsorption of Cu2+, Zn2+ and Ni2+ ions from weakly acidic effluents. © 2013 Elsevier B.V.

Stankovic V.,University of Belgrade | Gorgievski M.,University of Belgrade | Bozic D.,Mining and Metallurgy Institute Bor
Biomass and Bioenergy | Year: 2016

Cross-flow washing of wheat straw and beech sawdust with water was carried out in order to leach the alkali and alkaline earth metals from them. Incremental concentration change (C = δm/δV) of alkali and alkaline-earth metals in the leachate was plotted against the wash water volume. Maximum increase in δm/δV was achieved after passing 0.04 to 0.06 dm3 of water through the washed biomass. After passing 0.2 dm3 of water through the biomass, leaching of alkali metals was practically completed. Concentration of potassium ion was predominant in the leachate. From the whole amount of alkali and alkaline-earth metal ions, found in the aqueous phase after washing, K+ ions make about 80% in case of wheat straw and 64% in case of beech sawdust. Concentration of other considered metal ions was much less comparing to the potassium ones.Change in the pH and electrical conductivity (EC) were measured after passing of each portion of wash water through the biomass. Change of the EC against the wash water volume follows fairly the change of leachate composition. Based on the experimental results, the process of alkali and alkaline-earth metals leaching was modelled assuming the cross-flow scheme of leaching process. Proposed model follows fairly the experimental data. Discrepancy between the experimental and calculated values for alkaline-earth metals in case of beech sawdust is attributed to a different leaching mechanism. © 2016 Elsevier Ltd.

Stevic Z.,University of Belgrade | Radovanovic I.,University of Belgrade | Rajcic-Vujasinovic M.,University of Belgrade | Bugarinovic S.,Mining and Metallurgy Institute Bor | Grekulovic V.,University of Belgrade
Journal of Renewable and Sustainable Energy | Year: 2013

In this paper a brief overview of research in the field of electrode materials for solar cells and supercapacitors is presented, which the authors dealt with for years. In addition to the standard electrode material (graphite and silicon in supercapacitor with solar cells), different materials were examined, particularly oxides and sulfides of copper. Copper (I) oxide or cuprous oxide is an oxide semiconductor which is used as the anodic material in the form of thin film in lithium batteries and solar cells. The cathodic process of synthesis of cuprous oxide thin film is carried out in a potentiostatic mode from the organic electrolyte. The electrochemical characterization was carried out by cyclic voltammetry. The electro deposition techniques are particularly well suited for the deposition of single elements, but it is also possible to carry out simultaneous depositions of several elements and syntheses of well-defined alternating layers of metals and oxides with thicknesses down to a few nanometers. Electrochemical characteristics of covellite (CuS) are of importance from flotation and metallurgical point of view, due to its potential application in solid state solar cells and in photocatalytic reactions. Also, the compound CuS appears as an intermediary product or a final product in electrochemical oxidation reactions of chalcocite (Cu2S) which exhibits supercapacitor characteristics. Natural copper mineral covellite has been investigated in inorganic sulfate acid electrolytes, as well as in strong alkaline electrolyte. Different electrochemical methods (galvanostatic, potentiostatic, cyclic voltammetry, and electrochemical impedance spectroscopy) have been used in these investigations. © 2013 AIP Publishing LLC.

Jovanovic I.,Mining and Metallurgy Institute Bor | Miljanovic I.,University of Belgrade
Archives of Mining Sciences | Year: 2015

Flotation process modelling is not a simple task, mostly because of the process complexity, i.e. the presence of a large number of variables that (to a lesser or a greater extent) affect the final outcome of the mineral particles separation based on the differences in their surface properties. The attempts toward the development of the quantitative predictive model that would fully describe the operation of an industrial flotation plant started in the middle of past century and it lasts to this day. This paper gives a review of published research activities directed toward the development of flotation models based on the classical mathematical rules. The description and systematization of classical flotation models were performed according to the available references, with emphasize exclusively given to the flotation process modelling, regardless of the model application in a certain control system. In accordance with the contemporary considerations, models were classified as the empirical, probabilistic, kinetic and population balance types. Each model type is presented through the aspects of flotation modelling at the macro and micro process levels. © 2015 Archives of Mining Sciences.

Gomidzelovic L.,Mining and Metallurgy Institute Bor | Mihajlovic I.,University of Belgrade | Kostov A.,Mining and Metallurgy Institute Bor | Zivkovic D.,University of Belgrade
Hemijska Industrija | Year: 2013

We present the results of thermodynamic analysis of Cu-Al-Zn ternary system, which belongs to a group of copper-based shape memory materials. A general solution model was used for calculation of thermodynamic properties in the temperature interval from 1373 to 2173 K, in sections from Cu, Al and Zn corner, respectively, with following ratios of 1:3, 1:1 and 3:1. Additionally, based on the obtained results, ternary interaction parameters were determined using Mathematical Modeling System (MLAB).

Bogdanovic D.,University of Belgrade | Miletic S.,Mining and Metallurgy Institute Bor
Economic Computation and Economic Cybernetics Studies and Research | Year: 2015

Personnel evaluation is a multicriteria decision making problem that can significantly affect the future caracteristics and the performance of an organization. The aim of this paper is to demonstrate the implementation of an integrated approach that employs AHP and PROMETHEE together for selecting the most suitable personnel from existing organization manpower in process of its reorganization and downsizing. The essence of the problem is how to minimize subjectivism of decision maker(s), that unfortunately, dominates in this process in Serbia. The related problem includes a Serbian company’s department with five employers that has to be reorganized with reduction of employees on three. The AHP is used to analyze the structure of the personnel selection problem and to determine the criteria weights, and PROMETHEE method is used to obtain the final ranking. The results have shown that the proposed integrated method can be successfully used in solving managerial problems. © 2015, Academy of Economic Studies. All rights reserved.

Dimitrijevic S.,Mining and Metallurgy Institute Bor | Rajcic-Vujasinovic M.,University of Belgrade | Trujic V.,Mining and Metallurgy Institute Bor
International Journal of Electrochemical Science | Year: 2013

Nowadays, the cyanide and ferrous cyanide solutions are used in practice for gold plating. The traditional baths employed for soft gold as well as hard gold plating contain the cyanide complex, [Au(CN)2]-, as the source of gold, which release free cyanide ions during the plating. Those compounds are very toxic, and formation and maintenance of cyanide baths is expensive and risky for technical personnel; also, they attack photoresists used to delineate circuit patterns and bonding pads. Due to this reason, and especially in modern time, there is a trend of using the electrolytes without content of cyanides. These electrolytes are mainly based on some organic compounds. This article is an overview of the non-cyanide electrolytes for gold plating introduced into practice or only tested in the laboratory. The large number of investigated complexes fulfils the coating quality requests, but there are problems related to their stability. Decorative gold plating obtained from classic cyanide electrolyte and an electrolyte based on mercaptotriazole have shown similar characteristics such as microhardness, surface roughness, visual appearance and adhesion. At the same time, this bath remained stable in a period of at least nine months. © 2013 by ESG.

Alagic S.C.,University of Belgrade | Serbula S.S.,University of Belgrade | Toic S.B.,University of Niš | Pavlovic A.N.,University of Niš | Petrovic J.V.,Mining and Metallurgy Institute Bor
Archives of Environmental Contamination and Toxicology | Year: 2013

Copper production in the Bor region (east Serbia) during the last 100 years has influenced the quality of soil, water, and air. This pollution has endangered not only the biotope but all living organisms, including humans. Contents of arsenic (As) and cadmium (Cd) were analyzed in Betula sp. (birch) and Tillia sp. (lime) within the Bor region with the aim to investigate the bioaccumulation of these highly toxic, nonessential trace elements in selected plants, which may be important for biomonitoring and bioremediation purposes. The results of statistical data analysis showed that several factors influenced the bioaccumulation of trace elements in the examined plants, of which soil pH, soil content, and mechanism of accumulation were the main factors. The greatest As and Cd concentrations were found in plant material from the Bor center sampling site in the urban/industrial zone, which is in close proximity to the pollution source, due to the greatest metal concentrations in soil and the lowest soil pH. The low values of biological accumulation coefficients (bioconcentration factor 〈 1, mobility ratio 〈 1) pointed to a low rate of uptake and accumulation of As and Cd in lime and birch. Trace elements showed different patterns of behavior and accumulation in the trees. Lime showed a high ability of assimilation through leaves, whereas birch showed a better potential to express a linear correlation between concentrations in plant parts and soil. © Springer Science+Business Media New York 2013.

Tasic V.,Mining and Metallurgy Institute Bor | Jovasevic-Stojanovic M.,Vinča Institute of Nuclear Sciences | Vardoulakis S.,Public Health England | Milosevic N.,Mining and Metallurgy Institute Bor | And 2 more authors.
Atmospheric Environment | Year: 2012

Accurate monitoring of indoor mass concentrations of particulate matter is very important for health risk assessment as people in developed countries spend approximately 90% of their time indoors. The direct reading, aerosol monitoring device, Turnkey, OSIRIS Particle Monitor (Model 2315) and the European reference low volume sampler, LVS3 (Sven/Leckel LVS3) with size-selective inlets for PM 10 and PM 2.5 fractions were used to assess the comparability of available optical and gravimetric methods for particulate matter characterization in indoor air. Simultaneous 24-hour samples were collected in an indoor environment for 60 sampling periods in the town of Bor, Serbia. The 24-hour mean PM 10 levels from the OSIRIS monitor were well correlated with the LVS3 levels (R 2=0.87) and did not show statistically significant bias. The 24-hour mean PM 2.5 levels from the OSIRIS monitor were moderately correlated with the LVS3 levels (R 2=0.71), but show statistically significant bias. The results suggest that the OSIRIS monitor provides sufficiently accurate measurements for PM 10. The OSIRIS monitor underestimated the indoor PM 10 concentrations by approximately 12%, relative to the reference LVS3 sampler. The accuracy of PM 10 measurements could be further improved through empirical adjustment. For the fine fraction of particulate matter, PM 2.5, it was found that the OSIRIS monitor underestimated indoor concentrations by approximately 63%, relative to the reference LVS3 sampler. This could lead to exposure misclassification in health effects studies relying on PM 2.5 measurements collected with this instrument in indoor environments. © 2012 Elsevier Ltd.

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