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In this research, changes in annual and seasonal trends of mean temperatures were analyzed on the territory of the Rasina River basin (central Serbia). We used data from four meteorological stations during three periods: 1961–1989, 1990–2018, and 1979–2013. The change detection analysis has been conceded using the Pettitt’s test, von Neumann ratio test, Buishand’s range test, and standard normal homogeneity (SNH) test, while the linear regression, Mann-Kendall, and Sen's slope tests have been applied for trend analysis. The results show that the change in summer temperatures occurred shortly after 1980. The analysis results showed that inhomogeneous structures are generally observed between 1976 and 1984, between 1997 and 1998, and in 2006. The trend of all the data on annual basis showed positive increasing trend. The analysis indicated that the average annual, winter, and summer temperatures show significant increasing trend both in the longer period (1961–2018) and in the second part of the period (1990–2018). In the first part of the period (1961–1989), autumn temperatures in Kruševac, summer and autumn temperatures in Blace, as well as winter and autumn temperatures in Goč showed significant decreasing trend. The significant rising trend in the summer and winter months in the last 30 years may affect water availability and water demands in the region.

Depopulation of mountains has been an intense and lengthy process in Serbia. This paper will analyze the potential of Kopaonik mountain for the development of tourism, which can be one of the key factors for the demographic revitalization of the entire mountain. In tourism development so far, Kopaonik mountain stands out as one of the most important carriers of mountain tourism in Serbia. The limiting factor in the development so far is the pronounced seasonality of tourism promotion. The aim of the research in the paper will be to identify the factors that influence seasonality phenomena as the main limiting factor for achieving better economic effects.

Since there are large requirements for green energy sustainability, in this study, optimization of in situ transesterification of microalgae slurry conversion into biodiesel was performed. The main aim was to perform a selection procedure of the optimal predictors for fatty acid methyl ester yield and exergy efficiency in situ transesterification process. The adaptive neuro fuzzy inference system (ANFIS) as a soft computing approach was used for the optimization of the predictors for the fatty acid methyl ester yield and exergy efficiency. Based on the obtained results, the optimal combination for fatty acid methyl ester yield was ultrasonic power and reaction time while the optimal combination for the exergy efficiency was concentrations of methanol and chloroform in oil. These selected predictors could be used effectively in order to maximize the fatty acid methyl ester yield and exergy efficiency.

This paper analyzes water quality from four hydrological stations in the Nišava river basin from 2009–2018 based on the following parameters: pH, conductivity, O2 saturation, BOD5, suspended solids, total oxidized nitrogen, phosphates, turbidity and coliform bacteria. Authors have applied WQI (water quality index) as the most reliable indicator of the watercourses pollution for setting of surface water flow quality. Statistical analysis of variance (ANOVA) using t-test inferential statistical analysis and post-hoc Tukey test were applied to evaluate statistically significant differences between specific data groups. The results show that bad water quality was registered on all the profiles on an annual basis (WQI = 65–71). The river water pH decreases downstream, while values of BOD5, suspended solids, turbidity, TON, phosphates and coliform bacteria gradually increase. The waters of the Nišava at the station Niš belong to the third class of waters and they are mostly loaded with organic matter originating from waste sewage and industrial waters of both urban and rural areas.

This paper analyzes the karst landscape of Southeastern Serbia, Mount Kalafat. The evaluation of five representative caves was performed using M-GAM (modified geosite assessment model) and the perspectives and potentials of karst-based geotourism were presented, through speleology, paleoclimate, and archaeology. Moreover, a unique proposal was presented in the form of a karst protection project through the establishment of a karst theme park. Although there are other attractive karst regions in Serbia, Mount Kalafat has been taken as a study area, due to the willingness of the local management structures and authorities to support projects concerning the protection of geoheritage and the development of karst-based geotourism. The results of the research indicate the evident values of the karst geoheritage and geotourism potentials that can become significant indicators for the development of sustainable geotourism and geoconservation in this area. Thus, precise measures and sustainable strategies that could define the geoethical concept of geotourism development have been presented in this paper. © 2022, The Author(s), under exclusive licence to The European Association for Conservation of the Geological Heritage.

The turbulent geological past of the southeastern part of Serbia, along with the influence of the Nišava River, has created a rich and complex geodiversity. However, the geotourism potential of this area remains fully unrevealed. This paper proposes an inventory of geosites in the Niš City area (southeast Serbia) and analyses them to reveal which geosite possesses the greatest geotourism potential. The selected sites were evaluated by applying the Modified Geosite Assessment Model (M-GAM) to discover the most suitable geosites for future geotourism development. The main goal of this study is to emphasize the geotourism potential of the Niš City area and establish the current state and geotourism potential of geosites located there. The results point out that further geotourism development should primarily be focused on Cerjanska cave and Sićevo gorge. The results reveal information about the key fields of improvement for each evaluated geosite. Also, results identify which areas require more attention and better management in the upcoming period for this area to become a geotourism destination that would attract a larger number of tourists in the future.

The aim of this research is to determine the change in the spatial distribution of erosion intensity in the territory of the Jablanica River Basin in the period 1971&ndash, 2016 caused by land use and demographic changes. The Erosion Potential Method (EPM) was used to quantify changes in erosion intensity and to estimate the total annual sediment yield. The research results show that the value of the erosion coefficient decreased from 0.432 in 1971 to 0.360 in 2016. Specific annual gross erosion in the Jablanica River Basin was 654.41 m3/km2/year in 1971, while in 2016 it was 472.03 m3/km2/year. The analysis of proportional changes was used to determine demographic changes and land use patterns in the basin area. In terms of the scale and intensity of the erosion process, three types and one sub-type of population dynamics of settlements and land use changes were distinguished, respectively: progressive, stagnant, regressive and dominant regressive. It was concluded that the results show the significance of demographic and land use changes in the control of the intensity of erosion. The Soil Erosion Map may be useful to planners and land use managers to take appropriate decisions for soil conservation in the basin.

The Sokobanja basin is an area in Eastern Serbia with diverse geological and geomorphological features. Also, it is an area with developed spa tourism. The Sokobanja basin has numerous geoheritage features, which tourist potential has not been discovered yet. In this article, several geosites were analyzed, which present significant geoheritage formations. Geosites were selected by authors of this article based on the degree of their attractiveness for the geotourism development. The main goal of this article is to emphasize the geotourism potential of the Sokobanja basin and to determine the current state and geotourism potential of evaluated geosites by applying the modified geosite assessment model (M-GAM). A total of seven geosites were evaluated throughout the basin. The values of the investigated parameters were entered into the matrix of the M-GAM based on the number of points. Based on the research and the results obtained, it can be concluded that the Sokobanja basin has the potential for the development of geotourism, but it is necessary to improve additional values to become a true geotourism destination.

Serbia and the entire Southeastern Europe was affected by considerable demographic, political, and socioeconomic changes in the second half of the twentieth century. The changes in the population were shown as an insufficient birthrate as well as an intense emigration. Apart from these, certain drastic changes in the household structure occurred. This article examines the total changes in the household number on the territory of the Republic of Serbia, with the municipality of Sokobanja as a prominent example. Other aims of the research are the analysis of the household composition and economic characteristics of the households.

Periodicity of temperature on three stations in the Nisava River valley in period 1949-2014, has been analyzed by means of Fourier and wavelet transforms. Combined periodogram based on fast Fourier transform shows considerable similarity among individual series and identifies significant periods on 2.2, 2.7, 3.3, 5, 6-7, and 8.2 years in all datasets. Wavelet coherence analysis connects strongest 6-7 years spectral component to Mediterranean oscillation, starting in 1980s. Combined periodogram of Mediterranean oscillation index reveals 6-7 years spectral component as a dominant mode in period 1949-2014. Wavelet power spectra and partial combined periodograms show absence of 6-7 years component before 1975, after which this component becomes dominant in the spectrum. Consistency between alternation in temperature trend in the Nisava River valley and change in periodicity of Mediterranean oscillation was found. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. OI176008]

Rasina District is faced with serious demographic problems at the beginning of the twenty-first century which are the consequence of long-term economic and social changes both in this area and the country as a whole. The basic problem is insufficient population regeneration, which further leads to other negative processes. One of the most important problems of Rasina District is the ageing of population, i.e., a drop in young population and a significant rise in old population. Therefore, the population of Rasina District is already in the critical phase of demographic aging. Such age structure influences further economic development of this area at large. The decrease in young population, which is the carrier of future reproduction and regeneration of the population of this area, is evident. So as to stop or decelerate these processes, it is necessary to improve life conditions and ensure certain economic standard. Otherwise, these processes will not be stopped; they will be all the more intensified.

The changes and oscillations in air temperature during the second half of the 20th and in the early 21st century, have become one of the major concerns of almost all scientific disciplines. Such changes are noticeable both at the local and global level. The objective of this paper is to point out that the changes of this climate element can also be detected at the local level. The research underlying this paper is, in terms of territory, limited to the Sokobanja basin in Eastern Serbia. The analysis relies on the data on air temperature for the period 1946-2012 taken from the Meteorological weather station located in Sokobanja. The obtained data were processed in line with the recommendations of the World Meteorological Organization (WMO). The evidenced statistically significant changes in air temperature were examined using the following statistical tests: Pettit test, Standard Normal Homogeneity test, Buishand range test, and von Neumann test. [Projekat Ministarstva nauke Republike Srbije, br. ОI 176008]

An intensive process of demographic change in the City of Nis started in the second half of the 20th century. Socio-economic development of the territory caused the increase in population. While the city center demographically get stronger, peripheral urban areas of the municipality were stagnating or very slightly number grew its demographic score. Along with population growth, took place in the process of increasing the number of households that had a smaller number of members. The aging population is a particular problem which greatly affects economic growth. During the last decade of the 20th century, this area has gone through a transition phase where large number of industrial giants were closed. As a consequence it appeared the changes in the economic structure of the population.

The paper focuses on the possibilities of generating electrical energy by means of PV solar plants of 1 MW in Serbia. Further on basic physical characteristics of solar cells made of monocryistalline silicon, CdTe and CIS solar cells and a description of the fixed PV solar plants, one-axis and dual-axis tracking PV solar plants are given. The paper proceeds to tackle the legislative frame concerning renewable sources of energy and the current state of the use of PV systems in Serbia, climate conditions and energy potential of the renewable sources in Serbia. Apart from PVGIS solar map of Serbia real meteorological data for 17 towns in Serbia are given. Based on PVGIS program, geographycal position and the results of PVGIS calculation of the yearly average values of the optimal panel inclination, solar irradiation on the horizontal, vertical and optimally inclined plane, ratio of diffuse to global solar irradiation and linke turbidity for some cities in Serbia are given. Total for year sum of global irradiation per square meter received by the modules of the fixed PV solar plants, optimally inclined one-axis and dual-axis tracking PV solar plants of 1 MW and total for year electricity production of different types of PV solar plant of 1 MW for 23 cities in Serbia obtained by PVGIS are given. Comparison of total for year electricity production of different types of PV solar plant of 1 MW with monocrystaline silicon, CdTe and CIS solar modules, respective, for 23 cities in Serbia is given. Calculations performed by PVGIS program have shown that irrespectable of the type of PV solar plants, most electrical energy in Serbia can be generated by means of PV solar plants with CdTe solar cells. Some practical data and considerations given in this paper can be used by a customer or company keen to invest in the PV sector in Serbia. (C) 2012 Elsevier Ltd. All rights reserved.

This article focuses on the problem of population aging in the municipality of Bela Palanka typical for the most prominent demographic problems in the territory of the Republic of Serbia and characteristically marked by an unfavorable age structure. The authors tried to determine both spatial and temporal dimensions of the population aging process of the aforementioned municipality.

Cartographic generalization of the rivers is a very complex process in cartography. Cartographic generalization involves reduction of water flows, their length, width and the density of river basin with the reducing of the map scale. In this study we analyzed the ratio of the density of river basin and the size of the degree of generalization of the maps of different scale. The example is the Velika Morava river basin. Based on the results given here we get to the basic regularities of proportion of the degree of generalization of the density of river basin.

To analyze thermal regime of Sokobanja basin during 20th century we used the data from weather station in Sokobanja (300m above sea level). These data were processed and analyzed in 30-year periods, according to WMO recommendation, as well as in the period from 1991 to 2000. Thermal regime was analyzed through monthly, seasonal and annual arithmetic means, as well as on the basis of absolute maximum and minimum values. .

Sokobanja is one of the major tourist sites in Serbia. It has significant tourist potential. Nonetheless, tourism, as well as other economic activities in this region, is in deep crisis. This paper analyzes the advantages and disadvantages of tourism development in the spa area. According to a survey, there is a good basis to attract tourists, but further development requires higher investments, as well as greater involvement of local residents.

The river of Rasina arises on the slopes of the mountains of Goc and Zeljin, from spring arms of the Velika and Burmanska river. After the flow of 92.3 km, it flows into the river of Zapadna Morava 5 km downstream Krusevac, 134 meters above sea level. This work analyzes the frequency of occurrences of high and low waters, as well as their influence on the regime of Rasina and water management problems in its basin. .

The settlements of Sokobanja municipality underwent intensive changes in the second half of the 20th century. These changes were manifested on all components of demographic development and caused the alterations of the functional type of settlements .This work discusses the functional transformation of the settlements of Sokobanja municipality in the period from 1953-2002. Applying the quantitative methods ,it has been established that these changes led to the decrease in the share of purely agrarian settlements and the increase in the share of agrarian -service-providing and purely service-providing settlements. . U drugoj polovini XX veka u naseljima opštine Sokobanja došlo je do intenzivnih promena. Promene su se odrazile na sve komponente u demografskom razvoju, ali takođe je došlo i do određenih izmena u funkcionalnim tipovima naselja. U radu je predstavljena funkcionalna transformacija naselja opštine Sokobanja u periodu 1953-2002. godina. Određenim kvantitativnim metodama utvrđeno je da su promene išle pravcem smanjenja učešća čisto agrarnih naselja i povećanju udela agrarno-uslužnih i čisto uslužnih naselja. .

The Rasina river begins on the slopes of the mountains Goc and Zeljin from the springs of the rivers Velika and Burmanska. After 92 km it flows into the Zapadna Morava, 5 km downstream from Krusevac, at 134m altitude. In this study, the water quality of the Rasina in the territory of Krusevac will be analyzed, 35 km downstream from the Celije artificial lake, and also the quality of its confluents like: Gaglovska river, Trmcarska river, Lomnicka river. The testing of the Rasina water quality is performed on five profiles on the river itself, and on the mouths of its larger confluents. We will also talk about effluents of Krusevac industry and their influence on the water quality of the Rasina river, and about the possibilities of effluent control and removal of potential pollutants as well.

Ethnopharmacological relevance This study reports on the uses of medicinal plants and ethnobotanical significance of Mt. Rtanj, Eastern Serbia. The aim of the study was collecting information on plant utilization and creating the list of medicinal plants collected by local community in the region of Rtanj Mt. in Serbia. Methodology A group of generally elderly people from the region were interviewed, asked to identify a certain number of plant taxa used against various human ailments. A quantitative ethnobotanical comparison has been performed in relation to other studies concerning the central Balkan Peninsula. Results There is an inventory of 45 plant species recorded. At the family level, the most common in traditional usage were species of Labiatae (22%), Rosaceae (20%) and Compositae (13%). The results of the survey suggested that Hypericum perforatum was the most popular medicinal plant. Among the 7 different recorded types of preparation, the aerial parts of plants were the most popular (47.3%). The most frequently reported medicinal uses of herbal drugs include remedies for immune system (22.97%), respiratory system (15.77%) and digestive system disorders (15.32%). However, a comparatively small number of available plant species was used for medicinal purposes while the level of ethnobotanical diversity was lower when compared to adjacent regions. Conclusions Ethnobotanical knowledge in this area is decreasing due to high emigration rates during the last period. The historically developed ethnobotanical heritage should be preserved and promoted on the larger level, getting the special position in the future management plans for this area.

The climate of Sokobanja basin has a significant influence on forming the economic character of this area. In the relation with other, primarily physical-geographical characteristics, climate of the Sokobanja basin has one of the greatest influences on the activities of the people who live there. The aim of this work is to analyze the basic climate elements and accordingly perceive their influence on the development of agriculture, as one of the most important activities of the population of this area.