İnşaat Mühendisliği Bölümü / Department of Civil Engineering
http://hdl.handle.net/20.500.12566/21
2024-03-19T11:09:37ZA new spatial estimation model and source apportionment of aliphatic hydrocarbons in coastal surface sediments of the Nayband Bay, Persian Gulf
http://hdl.handle.net/20.500.12566/1836
A new spatial estimation model and source apportionment of aliphatic hydrocarbons in coastal surface sediments of the Nayband Bay, Persian Gulf
Partani, Sadegh; Danandeh Mehr, Ali; Maghrebi, Mohsen; Mokhtari, Rouzbeh; Nachtnebel, Hans-Peter; Taniwaki, Ricardo Hideo; Arzhangi, Amin
Hydrocarbons, originating from oil and gas industries, are considered a potential risk for Nayband Bay, a natural marine park with extended mangroves, located on the north coastlines of the Persian Gulf, Iran. This paper determines the potential sources and spatial distribution of hydrocarbons, especially aliphatic hydrocarbons (AHCs), in Nayband Bay through the simultaneous application of three indices in the coastline surface sediments. To this end, a field study was conducted in the inter-tidal coastal zones and wetlands. Sediment samples were taken from surface layers along four transects with four sampling points at different distances from the gulf. The hydrocarbon compounds of the samples including AHCs, total petroleum hydrocarbons, and heavy metals (Ni, V as crude oil indicators) were analyzed and classified to discover the pollution indicators. Pearson pairwise correlation and cluster analyses along with pollution indices were employed to describe the spatial distribution pattern of hydrocarbons, identify hot spots, and determine the potential origin of AHCs. Different interpolation scenarios based on topographic and oceanic features were proposed to detect the spatial dynamics of AHCs. The results revealed that hydrocarbons mainly originated from anthropogenic sources including oil and gas industries located far from the affected area. It was also concluded that the long-distance pollution transfer was based on oceanic currents and wind direction in the bay. The proposed scenarios showed that the mean concentration values of total organic carbon and total organic material vary in the range of 0.19 ppm to 0.4 ppm and 2.88 ppm to 3.20 ppm, respectively.
2023-01-01T00:00:00ZSpatiotemporal variations in meteorological drought across the Mediterranean Region of Turkey
http://hdl.handle.net/20.500.12566/1827
Spatiotemporal variations in meteorological drought across the Mediterranean Region of Turkey
Soylu Pekpostalci, Dilayda; Tur, Rıfat; Danandeh Mehr, Ali
In this study, meteorological drought across the Mediterranean Region of Turkey (MRT) was investigated using fuzzy c-means clustering and innovative trend analysis (ITA). To this end, long-term (1971–2021) observed precipitation data from 35 meteorological stations distributed across the MRT were used to cluster the region and calculate standardized precipitation index (SPI) at 3-, 6-, and 12-month (SPI-3, SPI-6, and SPI-12) accumulation periods. Moderate drought (MD), severe drought (SD), and extreme drought (ED) events, as well as their severity and duration, were determined at each station and cluster. The spatiotemporal variations in SPI showed that the study area has experienced mostly MD events in all seasons while there was also a significant number of SD and ED events during the study period. Considering SPI-3, Senirkent station, and considering SPI-6 and SPI-12, Dörtyol station have witnessed the maximum number of dry spells. The fuzzy cluster analysis revealed that the MRT can be examined in three clusters of the western coastal region, relatively low altitudes in the eastern region, and northern high altitudes that receive the lowest annual precipitation. The long-lasting MD, SD, and ED events were all observed in the western coastal cluster. The ITA at all clusters indicated that the number of MD, ED, and SD events has increased since 1995.
2023-01-01T00:00:00ZAn improved adaptive neuro-fuzzy inference system for hydrological drought prediction in algeria
http://hdl.handle.net/20.500.12566/1821
An improved adaptive neuro-fuzzy inference system for hydrological drought prediction in algeria
Achite, Mohammed; Gul, Enes; Elshaboury, Nehal; Jehanzaib, Muhammad; Mohammadi, Babak; Danandeh Mehr, Ali
Drought has negative impacts on water resources, food security, soil degradation, desertification and agricultural productivity. The meteorological and hydrological droughts prediction using standardized precipitation/runoff indices (SPI/SRI) is crucial for effective water resource management. In this study, we suggest ANFISWCA, an adaptive neuro-fuzzy inference system (ANFIS) optimized by the water cycle algorithm (WCA), for hydrological drought forecasting in semi-arid regions of Algeria. The new model was used to predict SRI at 3-, 6-, 9-, and 12-month accumulation periods in the Wadi Mina basin, Algeria. The results of the model were assessed using four criteria; determination coefficient, mean absolute error, variance accounted for, and root mean square error, and compared with those of the standalone ANFIS model. The findings suggested that throughout the testing phase at all the sub-basins, the proposed hybrid model outperformed the conventional model for estimating drought. This study indicated that the WCA algorithm enhanced the ANFIS model's drought forecasting accuracy. The proposed model could be employed for forecasting drought at multi-timescales, deciding on remedial strategies for dealing with drought at study stations, and aiding in sustainable water resources management.
2023-01-01T00:00:00ZA finite volume method for a 2D dam-break simulation on a wet bed using a modified HLLC scheme
http://hdl.handle.net/20.500.12566/1820
A finite volume method for a 2D dam-break simulation on a wet bed using a modified HLLC scheme
Salamttalab, Mohammad Milad; Parmas, Behnam; Mustafa Alee, Hedi; Hooshyaripor, Farhad; Danandeh Mehr, Ali; Vosoughifar, Hamidreza; Hosseini, Seyed Abbas; Maghrebi, Mohsen; Noori, Roohollah
his study proposes a numerical model for depth-averaged Reynolds equations (shallow-water equations) to investigate a dam-break problem, based upon a two-dimensional (2D) second-order upwind cell-center finite volume method. The transportation terms were modelled using a
modified approximate HLLC Riemann solver with the first-order accuracy. The proposed 2D model
was assessed and validated through experimental data and analytical solutions for several dam-break
cases on a wet and dry bed. The results showed that the error values of the model are lower than those
of existing numerical methods at different points. Our findings also revealed that the dimensionless
error parameters decrease as the wave propagates downstream. In general, the new model can model
the dam-break problem and captures the shock wave superbly.
2023-01-01T00:00:00Z