Zoran P. Popović

Mechanical coupling in homogeneously deformed single-wall carbon nanotubes.

We developed a full symmetry implementing method, based on classical molecular dynamics with the Brenner-Tersoff potential, for determining the optimal configuration of homogeneously deformed infinitely long single-wall carbon nanotubes. All nanotubes with diameter less than 1.3 nm are studied. Systematic analysis of the coupling between different types of deformation shows that, in the tubes with chiral angle close to zero and 30°, the torsion-induced circumferential strain is opposite to the induced axial strain. Also, torsion in zigzag tubes induces larger circumferential strain, but in armchair tubes it yields a larger axial strain. The influence of diameter on axial-stretching-induced torsion becomes significant only for narrow tubes. Finally, significant deviation from the linear dependence of axial-strain-induced radial deformation is found for zigzag tubes. The presented results are important for the calculation of electro-optical properties of nanotubes under strain.

Production results of various categories of pheasants reared under controlled conditions

The overview of domestic and foreign investigations of the effects of various intensity of ant feeding technique in various categories of pheasants. With the aim to increase number of pheasants in our country and in the world, for decades pheasant chicks are produced in pheasant farms up to the age of 5-8 weeks, and body mass of 400-450 g, after which they are released into the hunting grounds. The capacity of pheasant farms in Serbia is about 900.500 hatched chicks, and in the past four decades several tens of millions of artificially reared pheasants were released. The quality of feeding the brood stock of pheasants, which produce eggs for hatching incubator has a direct influence on number, mass and fertility of eggs, and on the mass of newly hatched chicks. The feed conversion ratio in chicks depends on the first place on energy and protein level, and also on biological value of protein. In domestic investigations of pheasant chicks feeding with the concentrate mixture with higher protein value (30% to 28 days of age and 24% to 42 days of age) and with lower stocking density (450 individuals in the group), had significantly bigger Final body mass (457.07 g) and higher daily gain (4.22 g in the first 13:31 and g in the second period), and with better feed conversion ratio.

Two-color pyrometer-based method for measuring temperature profiles and attenuation coefficients in a coal power plant

ABSTRACT A novel method and the appropriate instrumentation for the measuring of temperature profiles and attenuation coefficients in a combustion chamber of a coal-fired power plant are described. The instrument is based on a two-color pyrometer. Results were verified by the pneumatic Venturi pyrometer measurements, as well as by sampling unburnt particles using a cooled extraction probe.

Recommendations and Results of Supplemental Feeding of Pheasants Depending on the Season

Summary The quality and quantity of natural food resources and food from agricultural land vary considerably depending on the type of the hunting ground and the season. In order to achieve better body weight of the hunted pheasants, to preserve their number and achieve better reproductive potential of these birds, supplemental feeding is necessary. Previous studies have shown that feeding of pheasants in hunting grounds in all seasons, and especially during the winter, yields positive results. The achieved results, however, are significantly dependent on the degree of anthropogenic activity in the hunting grounds, as well as the amount of natural food. Moreover, nutrition must be adequate not only in terms of the quantity, but also the quality. This means that instead of single feeds (most commonly cereals: wheat, corn, etc.), complete mixtures should be used, which is a costly solution. However, pheasants aged five or more months are increasingly in demand for hunting on the polygons. Nevertheless, hunting in preserved nature and with a diverse wildlife fund will never lose its significance.

Analysis of the Features of Hunting Grounds in Serbia

Summary Covering almost the entire territory of Serbia, hunting grounds occupy a unique role not only in the country’s hunting practices but also in game management and wildlife conservation. Therefore, it is useful to be acquainted with their characteristics in order to manage game in a sustainable manner. Nevertheless, there has not been a proper study on the condition of hunting grounds in Serbia since the country’s transition process, which reshaped the hunting sector as a whole. The purpose of this research is to identify and analyze the features of hunting grounds in Serbia in order to establish a base for future scientific research and appropriate decision making. The research results were obtained on the basis of the data on 272 hunting grounds in Serbia, collated during the hunting year of 2012/2013 and compared with the last comprehensive hunting analysis at the national level in 2001. The analysis suggests that the regal hunting system is still predominant in Serbia. The quality of hunting grounds has been enhanced to a certain extent, although there are yet some challenges which pose a threat to sustainable management such as the oversized hunting areas, lack of employees and poor financial condition.

Threats and international tools for sustainable brown bear (Ursus arctos L.) management

Abstract Lavadinović V., Popović Z., Ristić Z., Beuković D.: Threats and international tools for sustainable brown bear (Ursus arctos L.) management. Ekologia (Bratislava), Vol. 32, No. 4, p. 345-351, 2013. Negative relation between humans and large carnivores with unprofitable management caused a decrease in abundance of the latter within their natural habitat. Main reasons for negative attitudes of humans towards large carnivores are damages, fear and unfamiliarity with their characteristics. Brown bear (Ursus arctos) is a European autochthonous large carnivore. Although it is not threatened at the global level, its abundance in Europe is limited to several populations. Protection has an important role in brown bear conservation, since they face different threats, mainly by negative human activities. Conservation of the brown bear is complicated due to its habitats overlapping with the human environment and also because brown bears require large territories. In order to protect brown bears more efficiently, it is important to identify the threats and to conduct the species protection by international recommendations and agreements. In this paper, we analysed brown bear distribution in Europe, abundance limitation factors and international conservation instruments.