ISSN 2738-0971 | eISSN 2738-1013
Bulletin of Natural Sciences Research
Open access journal | Double-blind peer review

Aleksandar Valjarević

Faculty of Geography, University of Belgrade, Belgrade, Serbia

Articles

Open Access Original Scientific Paper

RADON IN WATER FROM PRIVATE WELLS AND ITS CONTRIBUTION TO INTERNAL EXPOSURE OF POPULATION IN RURAL AREAS AT TOPLICA REGION, SOUTHERN SERBIA

by Biljana Vučković, Ivana Penjišević, Nataša Todorović, Jovana Nikolov, Dragan Radovanović, Aleksandar Valjarević

The results presented in this paper are part of the investigating of radon the concentrations from natural sources in the Toplica region. The results refer only to the radon concentrations in water from private captured wells at 12 locations. Radon concentration in water was measured by alpha spectrometry using the RAD 7 – RAD H2O system. The range of radon concentration is from (2.8±1.2) to (76.0±4.0) kBq/m3, and the contribution of radon released from water to the air in the premises was in range (0.8±0.3) to (22.8±1.2) Bq/m3. The annual effective doses of inhaled and ingested radon were determined, the mean values were (114.8±14.8) and (3.2±0.3) μSv/y.

View Full-Text DOI 10.5937/bnsr14-50472 Published: 02 Jul 2024
Open Access Original Scientific Paper

APPLICATION OF MANN-KENDAL (MK) TEST IN TREND ANALYSIS OF AIR TEMPERATURE AND PRECIPITATION: CASE OF MAČVA DISTRICT (SERBIA)

by Nikola Milentijević, Nikola Bačević, Dušan Ristić, Aleksandar Valjarević, Milana Pantelić, Dušan Kićović

Recent climate changes cause significant natural and socio-economic consequences. They represent one of the major environmental problems of the late 20th and early 21st centuries. Changes in temperature and precipitation play a significant role in understanding climate change issues. They include numerous extreme climatic events such as heat waves, droughts, forest fires and more. Looking at regional differences in temperature and precipitation regime change, Southern Europe, including the Republic of Serbia, occupies a special place. The Mačva district (3.272 km²) is almost four times as spacious as the Mačva area. The administrative-political division of the Mačva district is comprised of eight municipalities. The paper presents trends of two climate variables: mean annual air temperature and mean annual precipitation in the study area. In methodological sense, the main statistical procedure is the non-parametric Mann-Kendall (MK) test. Data from three available meteorological stations in the Mačva district (1949-2015) were used for the analysis. The presented results of the trends in air temperature indicate that there is a statistically significant positive trend in all-time series. In trends, precipitation amounts a statistically significant positive trend was observed in two time series, while in one there is no trend. The expressed trends, especially in the case of air temperatures, lead to the possibility of drought. Mačva district and Mačva have some agricultural importance in the Republic of Serbia. For these reasons, some adaptation to climate change is needed as arid conditions lead to fluctuations in agricultural yield.

View Full-Text DOI 10.5937/univtho10-24774 Published: 30 Jun 2020
Open Access Original Scientific Paper

ANALYSIS OF AIR TEMPERATURE TRENDS: CITY OF PODGORICA (MONTENEGRO)

by Nikola Bačević, Aleksandar Valjarević, Nikola Milentijević, Dušan Kićović, Marko Ivanović, Meliha Mujević

This paper presents the results of the analyzed trends for three categories of parameters: average annual air temperature (YT), average maximum air temperature (YTx) and average minimum air temperature (YTn) for the Podgorica Meteorological Station in the Republic of Montenegro. The aim of this paper is to present possible climate changes based on the results obtained from the analyzed air temperature trends. The methodology is based on the application of: a) linear trend equations, b) trend magnitudes and c) Mann-Kendall trend test. The data from the respectable meteorological station in Podgorica for the period from 1947 to 2018 were used in order to estimate the trend. The obtained results indicate a statistically significant positive trend for all analyzed time series. Analyzing the trend test hypotheses, it was concluded that in all three cases the Ha hypothesis prevails. Average annual air temperature in Podgorica increased by 1.4°C, average maximum air temperature increased by 2.5°C and average minimum air temperature increased by 0.6°C. In accordance with the trends analyzed, the increase in air temperature is dominant in the capital of the Republic of Montenegro.

View Full-Text DOI 10.5937/univtho10-24790 Published: 29 Jun 2020
Open Access Original Scientific Paper

CAUSES AND CONSEQUENCES OF DEPOPULATION IN THE MUNICIPALITY OF KURŠUMLIJA

by Milen Vasiljević, Danijela Vukoičić, Aleksandar Valjarević

The municipality of Kuršumlija is located in the South of Serbia, encompassing the area of 952 km². According to the census from 2011, it is inhabited by 19,213 people. During the last decades, the municipality is facing the rapid decrease in the number of inhabitants, caused by natural and social factors. The manuscript analyzes the demographic changes reflected in the migration and structure of population in the period after 1948, along with the beginning of the industrial development, to 2011, when the municipality experienced the crash of economy. The analysis established that the municipality of Kuršumlija became emigrational area, especially after the closure of large industrial facilities which were the pillars of development. The young ones and those able for work were forced to leave their hearths, in search for employment and survival. All the settlements of Kuršumlija were included in the negative demographic processes reflected in the constant decrease of population. Big problem was also the intensity of inhabitants’ ageing, and lessening of the percentage of young ones, which points out that the municipality is in the phase of the deepest demographic age. The worrying fact is that the tendency of the population rate decrease in the settlements of Kuršumlija ‘municipality is prolonged.

View Full-Text DOI 10.5937/univtho9-19242 Published: 18 Jul 2019
Open Access

DIGITAL TOPOGRAPHIC MODELLING IN CASE WITH HIGHER FLOOD IN THE MUNICIPALITY OBRENOVAC

by Aleksandar Valjarević, Dragica Živković

The town of Obrenovac is situated near the banks of three rivers, the Sava River, the Kolubara River and the Tamnava River. It looks like a modern town, though it has often developed in an unplanned manner. This causes huge problems as it thrives in a rough terrain, without a plan, which the communal infrastructure cannot follow. Today's needs in terms of spatial planning, envisaging projects and keeping track of a different kind of information on space demand that new technologies be applied since they make it possible for procuring efficient and reliable information as well as connecting and interconnecting various sorts of data. Also with advanced numerical GIS data and relief analysis we were successfully calculated consequence of the last big flood in 2014.

View Full-Text DOI 10.5937/univtho8-18679
Open Access

GIS MODELLING OF SOLAR POTENTIAL IN TOPLICA REGION

by Aleksandar Valjarević

In this paper we investigated possible potential solar area on Toplica region based on GIS (Geographical Information system) and using a special kriging method with the help of open sources GIS software Quantum GIS. This kriging method is very special to vectorized and calculated the small area. The statistical approach calculated between datasets of three meteorological stations (Niš, Prokuplje, Kuršumlija). Data using of insolation from that meteorological stations from the period of (1953-2013) is useful for a solution to calculating solar potential. The also used parameter is hypsometry of relief of the whole area of Toplica region. Area of Toplica region is 2.231 km2 with a population of 90600 citizens. Divided into fourth municipalities (Prokuplje, Žitoradja, Black, Kuršumlija). The GIS modeling indicates that ideal areas for solar development are located the potential places in Toplica region. Only 13.6 km2 of the head model scores that were in the 90-100% range. However, given the statewide high insolation values with minimal variance, solar projects may be better suited for small-scale residential or commercial projects.

View Full-Text DOI 10.5937/univtho6-10739
Open Access

CLIMATIC REGIONS OF KOSOVO AND METOHIJA

by Radomir Ivanović, Aleksandar Valjarević, Danijela Vukojičić, Dragan Radovanović

The Following the average and extreme values of climatic elements, specific climatic indices and field research, we can select three climatic types in Kosovo and Metohija - the altered Mediterranean, continental and mountainous type. The altered Mediterranean type is present in southern and western Metohija , to be specific, it affects the Prizren Field, the Suva Reka and Orahovac Valley as well as the right bank of the Beli Drim from Pecka Bistrica to the Serbia - Albania border. Gradually and practically unnoticeably, it transforms itself into a moderate continental type which dominates over the remaining valley and mountainous parts of Kosovo. It affects parts of northern Metohija, Drenica and the entire Kosovo valley along with smaller sidelong dells - Malo Kosovo and Kosovsko Pomoravlje. Because of their exquisite heights, the mountains that complete the Kosovo Metohija Valley have a specific climatic type, at their lower slopes it is sub - mountainous and at the higher ones it is typically mountainous. Within these climatic types, several climatic sub regions are present. Their frontiers are not precise or sharp. Rather, their climatic changes are gradual and moderate from one sub-region to the other.

View Full-Text DOI 10.5937/univtho6-10409