GROWTH CHARACTERISTICS OF SOME BLACK POPLAR CLONES

U poljskom pokusu osnovanom pri gustoći od 400 stabala·ha-1 u zaštićenom dijelu vlažnog zemljišta, tipa fluvisol, srednjeg Podunavlja, pjeskovito-ilovaste forme, istraživane su karakteristike rasta tri klona (sorte) crnih topola: "PE 19/66", "S6-7" i "M-1" starosti 11 godina. Karakteristike rasta promjera, visine i volumena srednjih stabala ukazuju na značaj izbora klona (sorte) crnih topola pri osnivanju nasada za razlčite namjene: klonovi "PE 19/66" i "S6-7" (Populus deltoides Bartr.) u istraživanim uvjetima staništa i gustoće postižu kulminaciju prosječnog prirasta volumena u starosti od 11 godina, pri čemu se postiže drvna masa od 220-290 m3·ha-1 namijenjenog za kombiniranu proizvodnju tehničkog i celuloznog drveta. Sorta "M1" (Populus × euramericana (Dode) Guinier) za 11 godina postiže kulminaciju tekućeg prirasta volumena te se procjenjuje znatno duži proizvodni ciklus i kvalitetnija struktura dobijenih sortimenata.Growth characteristics of three black poplar clones, PE 19/66, S6-7, and M-1, were investigated in the field experiment established at plant distance of 5m x 5m in the protected area of central Danube basin, on the fluvisol of sandy-clayey form, after ten years of culture development. The characteristics of diameter, height and volume growth of medium trees show significant differences among the investigated black poplar clones. The research clearly highlights the significance of the clone (species) of black poplar at establishing the plantation for different purposes: clones PE 19/66 and S6-7, (Populus deltoides Bartr.) under the research conditions of the habitat and planting distance reach the culmination of average volume increment 11 years since the beginning of planting, reaching a wood volume of 220-290 m3·ha-1 for the purposes of combined production of technical and pulp timber. Clone M-1, a hybrid of domestic and American black poplar (Populus x euramericana (Dode) Guinier), demonstrates different growth properties, while the culmination of average volume increment at age 15 since the planting is estimated to have a considerably better assortment structure

Optimization of the medium composition for production of antimicrobial substances by bacillus subtilis ATCC 6633

In the effort to overcome the increase in antimicrobial resistance of different pathogens, natural products from microbial sources appear to be the most favorable alternative to current antibiotics. Production of antimicrobial compounds is highly dependent on the nutritional conditions. Hence, in order to achieve high product yields, selection of the media constituents and optimization of their concentrations are required. In this research, the possibility of antimicrobial substances production using Bacillus subtilis ATCC 6633 was investigated. Also, optimization of the cultivation medium composition in terms of contents of glycerol, sodium nitrite and phosphates was done. Response surface methodology and the method of desirability function were applied for determination of optimal values of the examined factors. The developed model predicts that the maximum inhibition zone diameters for Bacillus cereus ATCC 10876 (33.50 mm) and Pseudomonas aeruginosa ATCC 27853 (12.00 mm) are achieved when the initial contents of glycerol, sodium nitrite and phosphates were 43.72 g/L, 1.93 g/L and 5.64 g/L, respectively. The results of these experiments suggest that further research should include the utilization of crude glycerol as a carbon source and optimization of composition of such media and cultivation conditions in order to improve production of antimicrobial substances using Bacillus subtilis ATCC 6633

Characterisation, availability, and risk assessment of the metals in sediment after aging

The behavior of metals in sediments after their disposal to land has important implications for the environmental management. The sediment from the Carska Bara (Serbia) was polluted with adequate metal salts in order to reach severe contamination based on the pseudo-total metal content of Pb, Cd, Ni, Zn, Cu, and Cr according to the corresponding Dutch standards and Canadian guidelines. The toxicity and fate of the metal in sediment depend on its chemical form, and therefore, quantification of the different forms of a metal is more meaningful than the estimation of its total concentration. In this study, fractionation of metals in sediment has been investigated to determine its speciation and ecotoxic potential, as well as evaluation of metal potential toxicity based on the simultaneously extracted metals (SEMs) and acid volatile sulfides (AVSs) analysis at the beginning of the experiment and after 5 weeks of sediment aging. The investigations suggest that Cd, Pb, and Zn have a tendency to associate with labile fraction, the most mobile and most dangerous fraction for the environment. Risk assessment code revealed their high risk. Copper and chromium showed low to medium risk to the aquatic environment. Nickel showed no risk to the aquatic environment. This was the case at the beginning and after 5 weeks of aging. Aging yielded an increased mobility of all metals based on the increased proportion in mobile fractions. The I [SEM pound (i) ]/[AVS] ratio was found to be > 1 both at the beginning and after 5 weeks of aging, with the ratio showing an increase with time. This ratio indicates the potential availability/toxicity and, according to the US EPA criteria, the samples belong to the group with probable negative effect. If particular metals are considered, only the I [SEM pound (i) ]/[AVS] ratio for zinc was > 1 at the beginning. After 5 weeks, the ratio was > 1 for zinc, lead, and copper. Comparison of the results of sequential extraction and the results of SEM and AVS analysis showed good agreement for lead and zinc

Removal of As(III) and Cr(VI) from aqueous solutions using “green” zero-valent iron nanoparticles produced by oak, mulberry and cherry leaf extracts

Abstract The production of nano zero-valent iron nanoparticles, using the extract from natural products, increased in recent years as it represents green and environmentally friendly method. Synthesis of green zero-valent iron nanoparticles (nZVI) using oak, mulberry and cherry leaf extracts (OL-nZVI, ML-nZVI and CH-nZVI) proved to be a promising approach for As(III) and Cr(VI) removal from aqueous solutions. The oak, mulberry and cherry leaves were chosen because of their high oxidant capacity as an important property for the production of the nZVIs. Also, oak, mulberry and cherry trees are widely distributed and easy to find in Vojvodina, the north province of Serbia. Characterization of produced green nZVI materials confirmed the formation of nanosize zero-valent iron particles within the size of 10–30 nm. Nanoparticles were spherical in shape and represented stable material with minimum agglomeration observed by TEM and SEM morphology measurements. Batch experiments revealed that the adsorption kinetics followed pseudo-second order rate equation. The obtained adsorption isotherm data could be well described by the Freundlich model. In addition, investigated pH effect showed that varying the initial pH value had a great effect on As(III) and Cr(VI) removal. This study indicated that nZVI could be produced by low cost and non toxic method with oak, mulberry and cherry leaf extracts and potentially be used as a new green material for remediation of water matrices contaminated with As(III) and Cr(VI)

Toxic metal immobilization in contaminated sediment using bentonite- and kaolinite-supported nano zero-valent iron

This paper reports from a pilot study conducted in an ongoing research project focusing on how users and their needs are being part of the development of smart grid services. The project aims to explore how development and use of services related to smart grids in homes might affect practices involving electricity consumption. The empirical material centers around an urban development project with a focus on social sustainability. So far only preliminary remarks can be made, and these points to that smart grid services are not in the center of attention, but rather taken for granted, and that the users are rather absent from the discussions. This indicates that the practices of which electricity consumption are part are not taken into consideration, but instead it is taken for granted that users shall adjust their needs based on information about electricity consumption patterns and prices