Vol. 6 No. 2 (2016)

Open Access Original Scientific Paper

KINETIC DETERMINATION OF GOLD(III) BASED ON ITS INHIBITORY EFFECT IN OXIDIZING HOMOGENOUS REACTION SYSTEM

by Ružica Micić, Snežana Mitić, Ranko Simonović, Dragana Sejmanović

Development and application of a simple, fast, green analytical kinetic method for the determination of micro-amounts of gold(III ) ions, were presented in this paper. The method was based on the inhibitory effect of traces of Au(III) ions on the redox reaction between disodium-6-hydroxy-5-[(4-sulfophenyl)azo]-2-naphtalenesulfonate (artificial azo-dye "Sunset Yellow FCF", E110 in further text selected as SY ) and hydrogen-peroxide, in alkaline media of borate buffer. All experimental parameters affecting to the determination: reagent concentrations, pH and temperature were investigated and optimised. Working experimental conditions are set according to the highest sensitivity of the proposed kinetic method for the determination of Au(III) ions. The linearity of the method was obtained within the range 1.97-59.07 μg/mL of Au(III) ions with relative standard deviation of 3.66- 0.43 %, respectively. The influence by possible interference effects by major ions on the determination of Au(III) and their limits are investigated, at the constant Au(III) concentration of 39.39 μg/mL. The results of Au(III) determination in samples obtained by proposed kinetic method and comparative ICP-OES method were statistically agreeable. Obtained results for Au(III) determination in analyzed samples, as well as the development and validation of the proposed analytical procedure have given and discussed.

picture_as_pdf View Full-Text DOI 10.5937/univtho6-11894 Published: 31 Dec 2016

Open Access Original Scientific Paper

THE LCR OF WIRELESS MACRODIVERSITY SSC RECEIVER IN THE PRESENCE OF GAMMA SHADOWED KAPPA-MU FADING

by Časlav Stefanović, Danijel Đošić

Wireless mobile macrodiversity (MaD) radio system with switch and stay (SSC) receiver and two microdiversity (MiD) selection combining (SC) branches operating over Gamma shadowed Kappa-Mu (k-µ) multipath fading environment is considered. Novel, one-folded integral expression for average level crossing rate (LCR) of MaD SSC receiver output signal envelope is obtained. Numerical results of the proposed model are presented and discussed in relation to the system model parameters.

picture_as_pdf View Full-Text DOI 10.5937/univtho6-12527 Published: 31 Dec 2016

Open Access Original Scientific Paper

CONTEMPORARY DEMOGRAPHIC CHANGES IN SETELLMENTS ALONG THE ADMINISTRATIVE LINE IN SERBIA TOWARDS AUTONOMOUS PROVINCE OF KOSOVO AND METOHIJA

by Danijela Vukoičić, Milena Nikolić, Jelena Raičević

The settlements along the administrative line in Serbia towards Kosovo and Metohija had a very turbulent demographic changes in the past. These changes have influenced the present. In this paper we investigated the depopulation process of this area which is intensified with the political instability, social and economic changes. The main goal of this research was to analyze the causes and effects in the reduction of the number of inhabitants, as well as the possibility of revitalizing the rural settlements of a given area. To obtain the desired results, we analyzed the existing literature and statistical data, used comparative and historical methods as well as implemented the field surveys. The application of the SWOT analysis to the researched area have showed us the strength, weakness, opportunities, and threats that can effect the process of revitalization of the village.

picture_as_pdf View Full-Text DOI 10.5937/univtho6-12758 Published: 31 Dec 2016

Open Access Original Scientific Paper

CAN THE TRANSFORMATION OF INSTRUCTION PROCESS INTO A VIRTUAL PLACE INDUCE A SHIFT IN BEHAVIORAL PATTERNS OF TEACHERS AND STUDENTS?

by Eugen Ljajko, Vladica Stojanović, Dragana Valjarević, Tanja Jovanović

The goal of this study is to reveal possible influence that the participants’ age and Information and Communications Technologies (ICT) usage in the instruction process can have on behavior that defines whether students and teachers belong to one of the Digital Native/Immigrant or Visitor/Resident groups. We collected data through two surveys that covered a total of 1273 students and 382 teachers from southern regions of Serbia. The surveys consisted of questions about availability of computers and internet, ICT use in the instruction process, and communication habits in the ICT-empowered instruction process. The first survey covered both, students and teachers that were involved in the instruction process mostly deprived of the ICT usage. The second survey covered participants of an instruction process that was successfully improved by an ICT usage. Data analysis shows a shift in communication patterns of teachers and a sharp improvement in computer use for educational purposes for both groups included in the surveys. The change is induced by a proper ICT usage in the instruction process. Conclusions that followed the data analysis lead us to better approaches in organizing ICT usage in the instruction process that enable participants fully employ their resources in order to improve teaching techniques and learning.

picture_as_pdf View Full-Text DOI 10.5937/univtho6-11953 Published: 31 Dec 2016

Open Access Original Scientific Paper

THE INFLUENCE OF NONLINEAR AND LINEAR DEFECTS ON THE LIGHT PROPAGATION THROUGH LINEAR ONE-DIMENSIONAL PHOTONIC LATTICE

by Slavica Kuzmanović, Marija Stojanović Krasić, Ana Mančić, Branko Drljača, Milutin Stepić

In this paper, the light beam propagation through one-dimensional photonic lattice, possessing one nonlinear defect and one linear defect, has been investigated numerically. Different dynamical regimes have been identified in terms of the distance between the two defects, position of the incident light beam, the width of linear defect, the values of nonlinearity and presence of the transverse kick. Strong localized modes on the defects, breathing and zig-zag modes in the area between defects have been observed. It has been concluded that the width of the linear defect placed next to the nonlinear one influences localization of the beam at the nonlinear waveguide. On the other hand, the nonlinear defect, regardless of the values of nonlinearity, have a small influence on the beam propagation in photonic lattice. It has been observed that the transverse kick of the initial beam leads to the distortion of localized structures. By launching the light beam towards defects, the reflection of light has been noticed. Presented results can be useful for different applications, such as blocking, filtering and routing of light beam through optical media.

picture_as_pdf View Full-Text DOI 10.5937/univtho6-12670 Published: 31 Dec 2016

Open Access Original Scientific Paper

CALCULATION OF THE FREQUENCY RESPONSE AND BANDWIDTH IN LOW NUMERICAL APERTURE STEP-INDEX PLASTIC OPTICAL FIBER USING TIME-DEPENDENT POWER FLOW EQUATION

by Branko Drljača, Slavica Jovanović, Svetislav Savović

Time-dependent power flow equation is employed to calculate frequency response and bandwidth of low numerical aperture step-index optical fiber excited with Gaussian-like light source with large width. Both, frequency response and bandwidth, are specified as function of the fiber length measured from the input end of the fiber. Analytical and numerical solutions are compared and good agreement between results is obtained.

picture_as_pdf View Full-Text DOI 10.5937/univtho6-12574 Published: 31 Dec 2016

Open Access Original Scientific Paper

NEW CONTRIBUTIONS TO THE KNOWLEDGE OF LEPIDORTERA FAUNA OF KOSOVO AND METOHIA (REPUBLIC OF SERBIA)

by Predrag Jakšić

Seven species of Lepidoptera – Triodia sylvina (Linnaeus, 1761), Trichiura crataegi (Linnaeus, 1758), Eriogaster lanestris (Linnaeus, 1758), Endromis versicolora (Linnaeus, 1758), Caradrina clavipalpis (Scopoli, 1763), Polymixis rufocincta (Gayer, 1828) and Oria musculosa (Hübner, 1808) were recorded for the first time in Kosovo and Metohia, Republic of Serbia. The next seven species- Trichiura crataegi (Linnaues, 1758), Lycia graecarius (Staudinger, 1861), Biston strataria (Hufnagel, 1767), Agriopis aurantiaria (Hübner, 1799), Erannis defoliaria (Clerck, 1759), Parasemia plantaginis (Linnaeus, 1758) and Euplagia quadripunctaria (Poda, 1761) were confirmed for the same area. Besides detailed faunistic data, illustrations of some adults are given.

picture_as_pdf View Full-Text DOI 10.5937/univtho6-12528 Published: 30 Dec 2016

Open Access Original Scientific Paper

THE EFFECT OF ALTITUTDE ON THE PRESENCE OF PLANT SPECIES IN STANDS FOR JUNIPERUS L. PLANT SPECIES ON KOPAONIK

by Predrag Vasić, Tatjana Jakšić, Nikola Đukic

In this paper we present an assessment of the altitude effect on the plant species presence in different plant communities – the species of Juniperus genus (Juniperus communis L., Juniperus oxycedrus L. and Juniperus sibirica Burgsdorf) on Kopaonik Mountain. Two juniper species (Juniperus communis and Juniperus oxycedrus) were recorded at altitudes ranging from 420 m to 1420 m, while the third species Juniperus sibirica was found at an altitude of 2100 m. It was determined that the plant communities with the presence of species of the Juniperus genus differ in botanical terms at different altitudes. It was found that there are plant species in certain communities that are present only at some altitudes, while others were present at almost all altitudes. The species of Hypericum perforatum L. is recorded in all of plant communities surveyed that proves its best adaptation to the conditions at different altitudes.

picture_as_pdf View Full-Text DOI 10.5937/univtho6-12389 Published: 30 Dec 2016

Open Access Original Scientific Paper

MODIFICATION OF TRANSITION'S FACTOR IN THE COMPACT SURFACE-POTENTIAL- BASED MOSFET MODEL

by Tijana Kevkić, Vladica Stojanović, Dragan Petković

The modification of an important transition’s factor which enables continual behavior of the surface potential in entire useful range of MOSFET operation is presented. The various modifications have been made in order to obtain an accurate and computationally efficient compact MOSFET model. The best results have been achieved by introducing of the generalized logistic function (GL) in fitting of considered factor. The smoothness and speed of the transition of the surface potential from the depletion to the strong inversion region can be controlled in this way. The results of the explicit model with this GL functional form for transition's factor have been verified extensively with the numerical data. A great agreement was found for a wide range of substrate doping and oxide thickness. Moreover, the proposed approach can be also applied on the case where quantum mechanical effects play important role in inversion mode.

picture_as_pdf View Full-Text DOI 10.5937/univtho6-11360 Published: 25 Dec 2016

Open Access Original Scientific Paper

HK DISTRIBUTION MODEL FOR ATMOSPHERIC TURBULENCE CHANNEL UNDER THE INFLUENCE OF POINTING ERRORS

by Marko Smilić, Stefan Panić, Milan Savić, Petar Spalević, Dejan Milić

In this paper, HK statistical model is considered. The application of HK distribution in modeling atmospheric turbulence channel under the influence of strong and weak turbulences and all irradiance fluctuations are discussed. Expression for atmospherics turbulence channel model, pointing error models and path loss are given. Probability density functions (PDF) for both pointing error models (zero boresight and nonzero boresight) are calculated and graphically represented. Also, average bit-error-rate (BER) for zero boresight pointing error and nonzero boresight pointing error are calculated and graphically represented. Closed form expression for PDF and BER are given. Impact of zero boresight pointing error and nonzero boresight pointing error on transmission over atmospheric turbulence channel in FSO system is explained.

picture_as_pdf View Full-Text DOI 10.5937/univtho6-12480 Published: 21 Dec 2016

Open Access Original Scientific Paper

SOME CYCLIC FIXED POINT RESULTS FOR CONTRACTIVE MAPPINGS

by Stojan Radenović, Sumit Chandok, Wasfi Shatanawi

In this paper, we obtained some new cyclic type fixed point theorems using C-class functions in the framework of metric spaces. Our results extend, generalize, improve and enrich some recent results in the existing literature.

picture_as_pdf View Full-Text DOI 10.5937/univtho6-11813 Published: 20 Dec 2016

Open Access

THE NUMBER OF ZERO SOLUTIONS FOR COMPLEX CANONICAL DIFFERENTIAL EQUATION OF SECOND ORDER WITH CONSTANT COEFFICIENTS IN THE FIRST QUADRANT

by Jelena Vujaković, Miloje Rajović

The study of complex differential equations in recent years has opened up some of questions concerning the determination of the frequency of zero solutions, the distribution of zero, oscillation of the solution, asymptotic behavior, rank growth and so on. Besides, this is solved by only some classes of differential equations. In this paper, our aim was to determine the number of zeros and their arrangement in the first quadrant, for the complex canonical differential equation of the second order. The accuracy of our results, we illustrate with two examples.

picture_as_pdf View Full-Text DOI 10.5937/univtho6-11621