The hydropower potential in the Republic of Serbia, as the most important renewable energy source, has been estimated at around 17000 GW•h per year, where approximately 2000 GW•h could be obtained from small hydropower plants (SHP). Small hydropower plants in Serbia currently produce 150 GW•h. Accordingly, the share of the electricity production from small hydropower plants in the total electricity production in Serbia is too small. The paper presents a model for the selection of optimal locations for small hydropower plants, which includes an ecological criterion, along with technical and economic criteria. The ecological criterion is eliminatory, i.e. those parts of the watercourse that border on or pass through protected natural assets are not taken into account when considering potential optimal locations for SHPs. All technical and economic criteria are included in the calculation of the weighted arithmetic mean with the aim of determining the optimal position for the construction of small hydropower plants. The model is implemented in the SHPOP software and its application is demonstrated on five watercourses in Southeastern Serbia.
This research analyzes the peaks-over-threshold (POT) method for designed flood estimation needed to plan river levees, spillways and water facilities. In this study, a one-parameter exponential probability distribution has been modified by including the coefficient of λ, which represents an average number of floods and enables return period calculation within the specified period of time. The study also compares results using the Log-Pearson Type III distribution of maximum annual flows and a standard exponential distribution of the selected peaks over the threshold level. The aforementioned approach represents the standard mathematical tools for river flood design, while the proposed modification of the exponential distribution highlights the estimation of flood quantiles with longer return periods (e.g., 100, 1000 and 10,000 years). Moreover, the sensitivity analysis of the threshold selection is proposed to assist in the flood design flow estimation alongside the proposed modification of the exponential probability distribution. The study was carried out at the Danube River, and the Novi Sad hydrological station (Republic of Serbia) was used for the long-term recorded period from 1876 to 2015. The results suggest that the POT method derives more reliable estimates of design floods than the traditional statistical tools for flood estimation. The results suggest the theoretical values of the water level of the 10,000 years return period is equal to 867 cm, while the Log-Pearson Type III distribution of annual maximum flows underestimated this value for 14 cm.
The paper deals with the influence of temperature changes on concrete pavement. Due to differences in temperature on the upper and the lower surface of a concrete slab, the bending stress is created, resulting in concrete slab deformation. During the process of heating, the difference in temperature between the upper and the lower surface of pavement is created as a result of heat conduction. The upper surface has a tendency to expand (tense), whereas the lower one does not alter its dimensions, which results in generating the bending stress. Concrete pavement is most commonly placed in zones with extremely heavy traffic load as well as at bus stops. The analysis was carried out at bus stops in the city of Novi Sad for three different types of slab thickness. The thickness of slabs was 20, 22 and 24 cm. The testing was conducted in the longitudinal and transverse direction of the concrete pavement, both in the middle and on the edge of a slab. During the analysis of results, a conclusion was drawn that the concrete slabs were of different dimensions and thickness, and that they were placed on different subgrade reactions. The maximum values of stress were recorded in the middle of a concrete slab, in slabs whose thickness amounted to 24 cm, while the minimum stresses were identified in slabs which were 20 cm thick. The paper presents the stresses of concrete slabs, caused by changes in temperature, which depend on the subgrade reaction and dimensions of concrete slabs.
The objective of this research was to determine the probability of road overtopping occurrence for a road culvert caused by surface runoff from the upstream catchment. A hydrological–hydraulic model was used for the development of an algorithm for road culvert maintenance based on the overtopping occurrence probability (CMOOP algorithm) for small mountain catchments. The hydrological model defines the regression dependence between the runoff hydrograph peak values and the probability of occurrences, whereas the hydraulic model calculates the culvert flow capacity by including in the calculation the level of sediment that culvert is filled with. The relationship between occurrences of overtopping and peak runoff value was defined using the runoff hydrograph transformation model in the accumulation on the upstream side of the road. In addition to the calculation of overtopping occurrence probability for the existing culvert condition, the CMOOP algorithm was used to analyze the impact of rehabilitation and reconstruction works from the perspective of legally based safety criterion for road overtopping occurrence probability (SCROOP). The CMOOP algorithm was appled to 67 concrete culverts located in a mountain road section in the Republic of Serbia. The results show that the application of rehabilitation works on selected culverts will increase the percentage of culverts that satisfy SCROOP from 49.25% to 89.55%, which confirms that the accumulated stone sediment is the main reason for the SCROOP unfulfillment.
СТАТИСТИЧКА АНАЛИЗА ПОЈАВА ВЕЗАНИХ ЗА ЛЕД НА ДУНАВУ КОД НОВОГ САДА Резиме: Извршена је статистичка анализа ледостаја и ледохода за Дунав код Новог Сада. Успешно је успостављена емпиријска кумулативна функција расподеле трајања ледостаја/ледохода, као и расподела учесталости ледостаја/ледохода најдужег трајања током зимског периода. Није се потврдила Пуасонова расподела броја ледостаја/ледохода у току зиме. У случају ледостаја трајања већег од 7 дана анализа је потврдила повећање водостаја током ледостаја.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.