Serbian energy development based on lignite production

Lignite, as an energy resource, is a mainstay of electricity generation in the Republic of Serbia. Installed capacity of lignite power plants represents 68% of the total installed capacity of Electric Power Industry of Serbia, the only company in Serbia, which manages electricity generation. In the future, with the increase in demand for electricity, both in Serbia and in Europe, we should expect more extensive and effective utilization of lignite as the main energy potential. In addition, due to increased emissions of CO₂, NO_X and other pollutants, the Republic of Serbia must accelerate the implementation of flexible mechanisms of Kyoto Protocol and the guidelines set by the European Union. Lignite in the future will retain its existential importance in the electricity generation in the Republic of Serbia.     

Comparative cavitation erosion test on steels produced by ESR and AOD refining

Cavitation erosion studies of steels produced by Electroslag Refining (ESR) and Argon Oxygen Decarburization (AOD refining) have been carried out. The experiments were conducted using the modified ultrasonically induced cavitation test method. Erosion rates were measured and the morphology of damages under cavitation action was studied by scanning electron microscopy and optical microscopy techniques. The present work is aimed at understanding the cavitation erosion behaviour of electroslag refined steel (ESR) compared with the steel produced by Argon Oxygen Decarburization (AOD refining), commonly used in the production of hydraulic machinery parts (Pelton blades). The results exhibited lower cavitation rate of ESR steel compared with AOD steel, as a consequence of its better mechanical properties and homogeneous and fine-grained microstructure.     

Study of the dielectric relaxation of poly(phenylpropyl acrylate) and poly(phenylpropyl methacrylate): effect of slight differences in chemical structure

A comparative study of the dielectric relaxational behaviour of two structurally close polymers, containing aromatic side groups, was carried out in order to analyse how slight differences in the chemical structure affect the molecular responses to perturbation field. Specifically, poly(phenylpropyl acrylate) (P3Ph1PA) and poly(phenylpropyl methacrylate) (P3Ph1PM) were studied using differential scanning calorimetry and dielectric relaxation spectroscopy in the frequency range 10^?2–10⁶ Hz and temperature window of ?80 to 120 °C. Both techniques show one glass–rubber transition for P3Ph1PA and two for P3Ph1PM, which evidence the great effect of the methyl groups on the segmental motions of the polymer. Phenomenological analysis of the data was carried out in order to establish the strength, width and fragility parameters of the glass–rubber transitions. In the case of P3Ph1PA, the strength is found to be larger than for P3Ph1PM, pointing out that the methyl group disturbs the mobility. Conductive processes dominate the dielectric spectra at high temperatures and low frequencies. © 2015 Society of Chemical Industry     

Characteristics of Wastewater Streams Within the Bor Copper Mine and Their Influence on Pollution of the Timok River,Serbia

Wastewaters produced by mining and metallurgical treatment of polymetallic sulfide ores have polluted the Timok River in Serbia for more than 100 years. We have characterized seven different wastewater streams within the RTB Bor facilities, investigating their influence on pollution of the Timok River before its confluence with the Danube River. Their relative contribution was calculated by considering the contaminant load of each wastewater stream and non-conservative transport along their flow paths. Three sampling spots in the Timok River, before and after its confluence with the Borska River, were also monitored.     

Validation of data on polycyclic biomarkers,naphthalenes, phenanthrenes,and alkyldibenzothiophenes obtained by gas chromatographic-mass spectrometric analysis of hydrocarbon concentrates

The possibility of using the data on the hydrocarbon composition obtained by analysis of hydrocarbon concentrates for geochemical studies has been shown on the example of Pannonian Basin (Serbia) crude oils of different genetic types and different degrees of thermal maturity and biodegradation. A high convergence of the values of geochemical parameters calculated on the basis of the composition of steranes and terpanes, alkylnaphthalenes, phenanthrenes, and dibenzothiophenenes in hydrocarbon concentrates and chromatographic fractions isolated from them has been found by correlation analysis.     

Droplet Size Distribution Obtained by Atomization with Two‐Fluid Nozzles in a Spray Dryer

The possibility of predicting the droplet size distribution from the particle size distribution was investigated. For that purpose, suspensions of different types of materials were dried in a laboratory‐scale spray drier. Drying of suspensions was performed with different sizes of two‐fluid nozzles. Droplet size distribution was evaluated from the data obtained for spray drying of bismuth molybdate suspension. The method was validated experimentally with other tested materials. Investigated systems involve processes of drying, crystallization, and coating. The proposed methodology can be applied when nonagglomerated particles, spherical particles, or spherical agglomerates were obtained by spray drying.