Showing 46 results for S. A.
D. Rajabi, H. Karami, Kh. Hosseini, S. F. Mousavi , S. A. Hashemi,
Volume 19, Issue 73 (fall 2015)
Abstract
Non-linear Muskingum model is an efficient method for flood routing. However, the efficiency of this method is influenced by three applied parameters. Therefore, efficiency assessment of Imperialist Competition Algorithm (ICA) to evaluate optimum parameters of non-linear Muskingum model was addressed in this study. In addition to ICA, Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) were also used to find an available criterion to verify ICA. In this regard, ICA was applied for Wilson flood routing then, routing of two flood events of DoAab Samsami River was investigated. In case of Wilson flood, the target function was considered as the sum of squared deviation (SSQ) of observed and calculated dischargem. Routing two other floods, in addition to SSQ, another target function was also considered as the sum of absolute deviations of observed and calculated discharge. For the first floodwater based on SSQ, GA indicated the best performance however, ICA was in the first place, based on SAD. For the second floodwater, based on both target functions, ICA indicated a better operation. According to the obtained results, it can be said that ICA could be recommended as an appropriate method to evaluate the parameters of Muskingum non-linear model.
H. Daliran Firouz, F. Mokhtari, S. Soltani , S. A. Mousavi,
Volume 19, Issue 74 (Winter 2016)
Abstract
Floods are considered as most destructive among all natural hazards which impose lots of damages on human societies. Hence, it is important to estimate such damages and losses and to determine flood impact areas for management plans. HEC-FIA software as a new model (Sep. 2012) was used in Ghohrood and Ghamsar watershed basins to estimate flood-driven losses and impacts. In this model, HEC-RAS and HEC-Geo RAS are used to produce inundation map in different return periods of flood as HEC-DSS file and by using the data collected in relation to regional agricultural land, building and human, human and financial losses are directly estimated. According to the results of this model, agriculture, building and human losses respectively in Ghohrood watershed are about 354 million rials with 24 buildings affected, and in Ghamsar watershed this is about 12879 million rials with 36 buildings damaged. The advantages of this model over the previous models are estimating the direct economic and human losses for what has occurred and for possible floods in the future. The results can help with watershed management, flood insurance and risk management.
Mohseni Movahed S. A.,
Volume 20, Issue 76 (Summer 2016)
Abstract
In the ICSSDOM simulation-optimization model, simulated annealing algorithm is combined with a hydrodynamic simulation model named ICSS. In this model the ability of weighting of indicators is also considered. In this study, using this model the performance of the S-L-R5 canal in the DEZ irrigation network was evaluated in a period of 10 days. With presenting a proposed method for weighting the indicators and its various options, using parametric sensitivity analysis, optimal adjustment of intake and check structures was obtained. It was found if the coefficient of each index is selected as a direct ratio of the ideal improvement potential of the indicator, the percentage of the improvement is more than the other investigated options. In addition, due to the interaction of the indicators in the multi-objective functions, the consistency of the weighting method with the nature of the optimization problem in this study has been shown. Statistically, the adequacy of the 10-day period of study was confirmed. The model validation with mathematical asymptote method shows 6% error which indicates the model is valid. For example, on the first day, based on the option three (The optimal option), the optimal gate opening for 5 intakes and one check control was between 3.9 to 14.7 Cm. In this condition optimal delivery was between 46 to 178 liters per second.
S. A. M. Mirmohammady Maibody, S. Dybaie, H. Shariatmadari, N. Baghestani,
Volume 21, Issue 2 (Summer 2017)
Abstract
The adaptability of Haloxylon appilium to adverse environmental conditions and especially its capability for an appropriate establishment in saline and desert soils has introduced this plant as a suitable means for biological methods to stabilize sand dunes, control erosion and prevent desertification in arid regions. In order to evaluate the ecophysiological characteristics of Haloxylon appilium some characteristics of soils under the long term establishment, survival and development of this plant and ion composition of this plant growing in Yazd province in thirty two growing trees of similar ages and traits within 8 locations of Chah Afzal and Ashkezar were investigated and their height (H), crown diameter (CD) and the above ground biomass index (Yi) were measured. Also, after cutting the trees from their collars, soil profiles were dug underneath the tree locations and soil samples were taken at depths of 0-30, 30-60, 60-90 and 90-120cm from four sides of each profile. The samples were then analyzed for Electrical Conductivity (EC), pH and Cl, Na, Ca, Mg, K concentrations in 1:5 soil to water extracts. The results showed statistically significant differences in soil parameters between the two regions, except for pH and Mg concentrations. The ion concentration of the plants in the two regions showed statistically significant differences for only Cl in shoots and Ca in roots. Based on the plant growth indices the Chah Afzal and Eshkezar regions were respectively evaluated as suitable and unsuitable for Haloxylon appilium growth. In spite of a higher salinity, the higher Ca and K concentration and lower Na/K ratio of Chah Afzal soils may explain the better plant performance in this region against Eshkezar, however, comprehensive researches on application of Ca and K fertilizer are needed to confirm this hypothesis
S. Shakeri, S. A. Abtahi,
Volume 22, Issue 4 (Winter 2019)
Abstract
This research was carried out to assess the origin and clay minerals characteristics and their relationship with potassium forms in the calcareous soil of this region, with the humid climate conditions. Based on aerial photos and topographic maps, physiographic units were separated and soil sampling was done in each diagnostic horizon. The results showed that smectite was the main and dominant clay mineral in the study area. In well-drained pedons, the convincing process for smectite abundance seemed to be mainly the transformation of palygorskite and mica. According to the results, the exchangeable potassium in the surface horizon was higher than that of the subsurface horizons. The main reason for the higher level of exchangeable K in the soil surface, was more smectite and organic carbon. The results revealed that unlike exchangeable and non-exchangeable K, because of the suitable conditions like temperature and humidity in surface horizons, the relative mean of structural K in the surface soils was less than that in the subsurface. Also, since an increase in calcium carbonate resulted in a decrease in amount of clay and the amount of relative clay minerals (dilution effect), the amounts of exchangeable, non- exchangeable and structural K were decreased.
S. A. Banishoaib, A. Bordbar, A. A. Kamanbedast, A. Masjedi, M. Heidarnejad,
Volume 23, Issue 4 (winter 2020)
Abstract
A ‘spillway’ is a structure used to provide the controlled release of flood water from upstream into downstream area of a dam. As an important component of every dam, a spillway should be constructed strongly, reliably and efficiently to be used at any moment. Labyrinth and stepped spillways are presented as appropriate modifications to those spillways hardly capable of managing the maximum potential discharge. Owing to their nonlinear crests for a given width, labyrinth and stepped spillways have a larger discharge rate than linear- crest spillways at an identical height. Compared to other energy dissipaters, the combination of stepped and labyrinth spillways is known as a very strong energy dissipater. In the following part, the combination of these two structures and their dimensional change for increasing the water- energy dissipation are addressed. To conduct this study, an experimental flume with a 90- degree bend in the Islamic Azad University of Ahwaz was used. In total, 90 experiments were conducted on three different labyrinth- shape stepped spillway models with two different lengths, three different widths, and five different discharges. Analysis of the results showed a greater energy loss reduction in triangular rather than rectangular or trapezoidal labyrinth- shape stepped spillways. In addition, energy loss was greater in labyrinth spillways with two cycles than those with one cycle. Energy loss was increased by raising the Froude number from 0.05 to 0.1; in contrast, energy loss was decreased with increasing the Froude number from 0.1 to 1.0, which was due to the submergence of steps, a decrease in the roughness of steps and an increase in the intensity of aeration.
