Showing 7 results for Malekian
R. Malekian, J. Abedi-Koupai, S. S. Eslamian, M. Afyuni,
Volume 17, Issue 63 (Spring 2013)
Abstract
Nitrogen (N) loss from irrigated cropland, particularly sandy soils, significantly contributes to nitrate contamination in surface and groundwater and increases N applications to crops. This is because negatively charged nitrate normally does not have much affinity to soil particles. To retard the movement of nitrate, materials should have high affinity for anions, which most naturally occurring minerals do not have. The cation-exchange properties of natural zeolites can be exploited to modify their surface chemistries so that other classes of compounds, particularly anions and non-polar organics are retained. In this study, the ability to remove nitrate from aqueous solutions with different Cl- concentrations using Iranian zeolite (Semnan) modified by hexadecyltrimethylammonium bromide in millimeter and nanometer particle sizes was determined and the equilibrium isotherms were characterized. The nitrate release as affected by time and ionic strength was also evaluated. It was demonstrated that SMZ is capable of adsorbing more than 60 mmol kg-1 and 80 mmol kg-1 nitrate in millimeter and nanometer sizes, respectively, and adsorbed nitrate can be easily released under different ionic strengths. The millimeter and nanometer-sized SMZ showed 26.7% to 82.3% and 37.8% to 85.5% nitrate removal efficiency, respectively. The average of nitrate released by millimeter-sized SMZ was 6.92 mmol kg-1 in deionized water while it was 14.68, 22.71, and 34.91 mmol kg-1 in releasing solutions with ionic strengths of 0.03, 0.1, and 0.3 M, respectively
R. Malekian, J. Abedi-Koupai, S. S. Eslamian,
Volume 18, Issue 68 (summer 2014)
Abstract
In this study, the effect of clinoptilolite zeolite, as a soil amendment, on the parameters related to water and nitrogen movement in soil was investigated. Parameter and uncertainty estimation in the unamended (control) and amended soil
(Z), was performed using the sequential uncertainty fitting algorithm (SUFI-2) which is linked to LEACHN (in the LEACHN-CUP software). The goodness of prediction uncertainty was judged on the basis of P-factor and R-factor. P factor, R-factor, and Nash-Sutcliffe coefficient (NS) was obtained 0.71, 0.76, and 0.92, respectively, in the prediction of the accumulated drainage from control. The results in prediction of the accumulated drainage from Z treatment using hydraulic parameters obtained in control were satisfactory (P-factor = 0.87, R-factor = 0.78, and NS = 0.87). P-factor, R factor, and NS were 0.87, 1.36, and 0.91, respectively, in the prediction of NO3-N leaching at control. According to the P-factor and R-factor values (P-factor = 1, R-factor = 2.46), application of the control parameter ranges in the prediction of NO3-N leaching at Z treatment produced a large uncertainty. By adjusting the parameters in control for zeolite amended soil, the estimated values for denitrification rate, distribution coefficient, and soil/solution NO3-N nitrification rate were greater in zeolite-amended soil compared to control.
A. Malekian, H. Alipour, M. Kheirkhah Zarkesh, S. Gharachelo,
Volume 18, Issue 69 (fall 2014)
Abstract
Determine appropriate locations with accuracy and speed required is for Floodwater spreading very important. The main objective of this research, preparation, use and evaluation decision support systems is based on GIS and RS techniques to identify and prioritization appropriate areas Floodwater spreading in the study area. In this study area suitable for flood water spreading were selected based on major criteria four, sub criteria eight and index twentyfour. Finally five scenario will be provide and assessment (a scenario based on the relative values for the criteria four, and different scenarios four based on the obvious one of the main criteria). Comparison desirability average among the scenarios five indicate that it is Sub watershed (1) In the scenario third (infilteration preferred, water application preference and equality of all the main criteria) had a higher average desirability therefore between Sub watershed 2 in this scenario is preferred more than the other Sub. Of between the two sub watershed ivar region considering that the desirability average, sub watershed (1) and implemented of between scenarios, scenario (1) (infilteration major criteria preferred) were selected as first priority. Second priority for Floodwater spreading site selection is belong to sub watershed 2, and with scenario (1).
Z. Feyzi, A.r. Keshtkar, A. Malekian, H. Ghasemieh,
Volume 20, Issue 76 (Summer 2016)
Abstract
Shortage of rainfall and also relatively high intensity precipitations in short-term are characteristics of arid regions of the world, such as central of Iran. Studies have indicated that massive flooding causes great loss of life and properties every year. Also, Water scarcity in arid and semiarid regions of the world will cause fragile living conditions in these areas. Therefore, it is needed to reduce runoff rates using actions such as dam construction or artificial recharge techniques. In this study, seven factors were applied such as the slope, surface permeability, transmissibility in alluvium, alluvial quality, land use, runoff volume and thickness of the unsaturated layer to determine suitable areas and site selection for flood spreading and artificial recharge in south of Kashan plain. After preparing the digital layers, criteria weights were determined using Fuzzy AHP. The weighted maps were acquired and merged together. Results indicated that land use criterion with the greatest weight (0.22) was determined as the first priority in the site selection for flood speading. The parameters of runoff volume, permeability, slope, depth of the unsaturated layer, alluvial quality, and transfer coefficient were accounted as the second to seventh priorities.
S. Pishyar, H. Khosravi, A. Tavili, A. Malekian,
Volume 21, Issue 4 (Winter 2018)
Abstract
In this study, to study the status of water resources degradation in Kashan region, Isfahan Province, eight indices including: drop in groundwater, water salinity, irrigation efficiency, Well-to-Qanat development ratio, the pumping time, shortage of water supplies for animals and humans and the water negative balance were selected according to previous studies conducted on desertification in Iran and the world. Existing evaluation models were determined. Desertification map of the study area was provided according to MEDALUS model and selected indices. The selected indices were weighted using a multi-criteria decision method and each index having weight more than 0.5 were selected as the most effective indices of desertification. Again, the desertification status map of the study area was prepared by the most effective indices. Finally, the two desertification maps were compared. The results showed that the drop in groundwater, water salinity, the pumping time and water negative balance have the most effect on water resources degradation among selected indices. The results of comparing two groundwater degradation maps showed that based on map provided with eight indices, 87.78 and 8.30 percent of the total area are classified in critical conditions c and b, respectively. While the map provided by the most effective indicators shows that 99.15% of the total area is classified in the critical condition "c" and just 0.849% is classified in the critical condition "b". It can be concluded that to assess desertification status, it is better to first determine the indicators by weighting and prioritizing methods. This will identify the indicators that have not had a significant effect on the desertification phenomenon in the area and prevent their impact on desertification classes and reduction of scores.
D. Ziaei, R. Zare Bidaki, A. A. Besalatpour, A. Malekian,
Volume 23, Issue 4 (Special Issue of Flood and Soil Erosion, Winter 2019)
Abstract
To preserve soil as a productive resource, a balance between natural capability and utilization must be established to achieve through land suitability evaluation. The aim of this study was to compare the run-off and deposition of different land uses of Beheshtabad watershed in the current situation and in compliance with standardized land use fitted situation. For this purpose, land use map in its current state was provided using Landsat 7 images and land use suitability map was obtained by FAO (1979) instructions. SWAT model was then applied to simulate runoff and sediment yield by using these land use maps. To do this, the curve number method was used for calculating the runoff, the Muskingam was applied for channel routing, and Hrgrave-samani was employed for potansial evapotranspiration. The results confirmed that considering suitability in using lands in Beheshtabad watershed caused the reduction of the average runoff from 99.4 mm/yr to 82.8 mm/yr (17%) and sediment rate of 10.7 to 7.8 t/ha. yr (27%). Also, the reduction percentage in some land uses, such as dry, irrigated cropland and downstream ranges, was much more.
A. Malekian1, A.a. Jafarazdeh, Sh. Oustan, M. Servati,
Volume 26, Issue 2 (ُSummer 2022)
Abstract
To study the soil-landscape change in the Chaldoran region, 9 representative soil profiles were studied in 5 dominant geomorphic units of the study area including piedmont plain, mantled pediment, alluvial fan, plain, and flood plain. The results showed that the accumulation of pedogenic carbonate in some soils was concretion and light in color. In control soils in the piedmont plain (profile 5 and 7), mantled pediment (profile 6), and flood plain (profile 8) clay transferred from the surface horizons and accumulated in the lower horizon, due to relatively good rainfall in the region and distinct dry and wet seasons has led to the formation of argillic horizons along with the formation of crust on the surfaces of aggregates and building units and has formed the Alfisoils order. Mineralogical results showed the presence of chlorite, illite, kaolinite, and smectite minerals. According to the evidence, illite, chlorite, and kaolinite minerals were inherited and smectite minerals were formed due to weathering and evolution of illite, chlorite, or palygorskite minerals. Also, the results of the CIA index in the region indicated that the soils of the region are in the stage of weak to moderate weathering. In general, the results indicated the critical role of drainage, land use, and parent materials in the soils of the study area.
