Cyclic voltammetry was used for the characterization of zinc electrodeposition on steel from ethaline deep eutectic solution (1:2 choline chloride: ethylene glycol). The influence of ...4-hydroxy-benzaldehyde (HBA) as an additive was analyzed. It was shown that hydrogen evolution is inhibited in the presence of HBA and further significantly retarded upon addition of Zn2+ to the solution containing HBA. The cathodic peak for Zn2+ reduction in this type of ionic liquid (ethaline+HBA+Zn2+) resembles the zinc reduction in aqueous solution. The corrosion resistance of Zn coatings deposited at different current densities was evaluated by electrochemical methods, i.e., polarization measurements and electrochemical impedance spectroscopy in 3 % NaCl solution. The possibility of Zn?Mn alloy deposition from ethaline deep eutectic solvent was investigated for the first time. In addition, the corrosion stability of these alloy coatings was analyzed and compared to the stability of bare Zn coatings. It was shown that the optimum deposition current density for both Zn and Zn?Mn coatings with increased corrosion stability from ethaline + HBA electrolyte is 5 mA cm?2.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The aim of this paper is electrodeposition of Zn/CeO
2
and Zn-Mn/CeO
2
nanocomposite coatings. Four plating solutions were used (R1–R4). Solution R1 was without manganese ions, whereas solutions R2, ...R3, and R4 had Mn
2+
/Zn
2+
ratios of 1:1, 1:2, and 2:1, respectively. Electrodeposition is performed galvanostatically at 1 A dm
−2
, 2 A dm
−2
, and 4 A dm
−2
current densities with ultrasonic bath assisted mixing. The morphology of the coatings was observed using optical and scanning electron microscopy, the chemical compositions were determined using energy dispersive x-ray spectroscopy, whereas electrochemical impedance spectroscopy and potentiodynamic polarization method were used to determine the corrosion resistance of the coatings. All the solutions yield compact coatings with a small grain size and surface roughness ranging from 0.6 to 1.47 μm at all current densities. The results suggest that with the increase in current density, the content of manganese in the coating decrease, whereas the content of CeO
2
particles increases in Zn-Mn/CeO
2
coatings. Corrosion resistance of the coatings obtained from R2, R3, and R4 solutions deposited at lower current densities is higher compared to the coatings deposited from solution R1. The coating with the highest corrosion resistance was obtained from solution R2 at 1 A dm
−2
current density.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Electrochemically deposited Zn–Ni–Co alloys under various deposition conditions were investigated using atomic absorption spectroscopy for the determination of the chemical composition, atomic force ...microscopy for surface morphology analysis, and electrochemical impedance spectroscopy for determination of corrosion properties. The influence of the ratio of the alloying elements, Co2+/Ni2+, in a chloride deposition solution, as well as the deposition current density, on the chemical content, morphology and corrosion properties of the ternary alloys was studied. The plating solutions used were with the sAMe overall metal concentration, free of additives and the deposition was realized at room temperature. It was shown that the deposition of the ternary alloy coatings was of anomalous type and that the ratio of nickel to cobalt ions in the plating solution, as well as the deposition current density, had a significant influence on the chemical composition and corrosion stability of these coatings. The presence of both Ni and Co was beneficial for their corrosion stability. It was shown that morphology and porosity were important factors in the corrosion stability of these coatings. The coating deposited from the solution with higher Co2+/Ni2+ ratio at 8 A dm-2 was made up of the smallest crystalline aggregates, had a small surface roughness and porosity, and was with quite uniform distribution of agglomerates and it exhibited the best corrosion stability.
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The effect of increased acetate concentration on the process of enhanced biological phosphorus removal was investigated in a sequential batch bioreactor treating synthetic wastewater in a 6-h cycle. ...Anhydrous sodium acetate was used as the sole carbon source during the experiment and corresponded to a chemical oxygen demand concentration. The phosphate-accumulating organisms were initially cultured for 70 days and the chemical oxygen demand concentration was gradually increased to the final concentration of 1800 mgO
2
L
−1
under conditions suitable for the growth of the phosphate-accumulating organisms. Successful cultivation of the phosphate-accumulating organisms was only possible if the acetate concentration in the influent did not lead to an excessive concentration of residues in the sludge after the anaerobic phase (estimated at a chemical oxygen demand concentration of 100 mgO
2
L
−1
), which then passed into the aerobic phase. Cultivation continued for the next 67 days. During this time, the sludge was exposed five times to high acetate loading at different concentrations (corresponding to a chemical oxygen demand concentration of 250–1000 mgO
2
L
−1
) to test the performance of the enhanced biological phosphorus removal. High acetate concentrations had no effect on the anaerobic phase of enhanced biological phosphorus removal, as the phosphate-accumulating organisms performed well in anaerobic phosphorus release and acetate assimilation in all five tests. However, the effect of residual acetate in the aerobic phase was detrimental to the aerobic phase of enhanced biological phosphorus removal, as the phosphate-accumulating organisms were prevented from assimilating phosphorus in the aerobic phase.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This paper presents the analysis and comparison of energy and environmental properties of various city bus systems: diesel and compressed natural gas internal combustion engines, trolleybus, and ...battery electric bus. It is based on experimental research on fuel and energy consumption of city buses with aforementioned propulsion systems carried out under similar driving conditions – on the same city bus lines in Belgrade and Novi Sad, and on evaluation of energy efficiency and CO2 emission of real electricity production in Serbia. In this way, “tank-to-wheel” and “well-to-wheel” energy consumption and CO2 emissions of considered bus driving systems have been evaluated and compared. The results show all complexity of the matter since benefits of application of different systems largely depends on bus exploitation conditions and even more of the conditions of electric energy production. The compressed natural gas internal combustion engine compared to the Diesel engine provides obviously benefit in harmful gas emissions. However, CO2 emissions are on a similar level, while energy efficiency is even less. Electric propulsion systems provide undoubtedly benefit in energy consumption, harmful gases and CO2 emissions if tank-to-wheel conditions are considered, but well-to-wheel characteristics strongly depend on the condition of electric energy production.
This review paper considers possible instrumentation for diesel engine fine particles exhaust emission evaluation. The modern diesel engines have extremely low particles emission almost at the level ...of measurement error of existing gravimetric measurement method. Since coarse particles are eliminated by new engine technologies, fine particles, with very negative effects on human health, dominate in the emission of current diesel engine. Therefore, it is necessary not only to measure mass of emitted particles but also to investigate other important particle characteristics as: particles number, particle size, particle number and mass distribution, particle active surface, particle composition etc. Therefore, existing measurement technologies used in aerosol science can be used also to study diesel engine particles properties. This most common instrumentation in aerosol technique is shortly reviewed in the paper with special attention on candidate instruments included in EU program on portable emissions measurement systems (PEMS).
To determine the presence of nutrition labels on pre-packaged food products, as well as to analyse the types of presentation.
This was a descriptive study. The following characteristics were ...analysed: (i) presence and placement of the nutrition declaration (either as front-of-pack (FOP) or back-of-pack (BOP)); (ii) content of the presented information; (iii) presence of nutrition and health claims; and (iv) legibility of the written information. Settings Three different types of retailers in Belgrade, Serbia.
A total of 2138 pre-packaged food products from ten categories.
A nutrition declaration was found on 65.9% of all tested products. It was displayed on the back of the packaging of 62.7% of products and on the front of the packaging of 19.1% of products. BOP was the most commonly observed in breakfast cereals, soft drinks, milk and instant soups (in total over 90%), and the least common in meat products (21.5%). FOP was predominantly displayed on breakfast cereals (65.0%) and the least frequently on milk products (2.4%). The 'Big 4' (energy value, protein, carbohydrate and fat contents) and the 'Big 4 with additional information' figured on 40.9% of products. The 'Big 8' ('Big 4' plus sugar, saturated fat, fibre and sodium contents) and the 'Big 8 with additional information' were present less frequently (20.5%). Nutrition claims and health claims appeared on very few products (6.6% and 6.3%, respectively). The proportion of products with insufficient legibility was 31.5%.
Nutrition labelling in Belgrade, Serbia is not satisfactory. Mandatory regulations may be the best way to improve the current situation.
Three new endemic species of the genus Roncus L. Koch (Neobisiidae,
Pseudoscorpiones) from eastern Serbia have been erected, described and fully
illustrated. Their main characters and important ...diagnostic features have
been analyzed and compared to those of their closest congeners from the area
studied.
A complex mixture of compounds was identified from the secretion of specimens
of Unciger transsilvanicus. Phenol and p-cresol were detected for the first
time in the family Julidae, and for the ...second time in the order Julida.
Thirteen quinones were identified, with a great relative abundance of
toloquinone and 2-methoxy-3-methyl-1,4-benzoquinone. Hydroquinone was
detected for the first time in the order Julida. Besides these compounds,
isopentyl hexacosatetraenoate and isopentyl esters of saturated and
unsaturated fatty acids with chain lengths from C14 to C20were identified.
The most abundant non-quinone compound was isopentyl eicosenoate. The
relative abundance of quinone and non-quinone in the defensive fluid of U.
transsilvanicus was 77% and 23%, respectively. The phylogenetic importance of
the registered compounds is briefly discussed.
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