Time filter

Source Type

Lack S.,Islamic Azad University | Marani N.M.,Islamic Azad University | Mombeni M.,Islamic Azad University at Ramhormoz
Advances in Environmental Biology | Year: 2012

This research was conducted in order to investigate the effects of planting date on the grain yield and yield components of three rice cultivars in Khouzestan climatic conditions (South-west Iran) this research was conducted as a split plot using Randomized Complete Block Design (RCBD) with three replications in the 2010 cropping season in the research field of Khuzestan Agricultural Research and Natural Resources Center(Shavoor agricultural research station). In this research the dates 5 th May 25 th May and 15 th June were considered as the main factor in the main plots and the rice cultivars Hamar RedAnbarbou and Danial were regarded as the secondary factors in the sub plots.The results showed that planting date significantly affected grain yield biological yield harvest index 1000 grain weight fertility percentage the number of filled grains per panicle and the number of fertile tillers. The second planting date exhibited the highest grain yield with an average of 6018.3 kgha -1 and the first planting date assumed the lowest grain yield. The cultivars had a significant difference in terms of the abovementioned attributes. Danial and Hamar cultivars featured the highest grain yield with averages of 5591 and 55549 kgha -1 respectively; the lowest amount belonged to Red Anbarbou cultivar.Theinteraction effects of planting date and cultivar was significant on all attributes except for panicle length. The highest grain yield belonged to Danial cultivar in the second planting date with an average of 6902.6 kgha -1 while the lowest was obtained for Red Anbarboucultivar on the first planting date. Both delayed and early planting resulted in the decline of grain yield of rice cultivars. The reason for these reductions was the shortening of the vegetative growth period in delayed planting andthe coincidence of the flowering stage with environmental high temperaturesin earlier planting dates compared to the desirable state. Thus Danial cultivar on the second planting date is recommended for cropping in Khouzestan climate conditions. Source

Fuladipanah M.,Islamic Azad University at Ramhormoz | Jorabloo M.,Islamic Azad University at Garmsar
Ecology, Environment and Conservation | Year: 2014

Water flow management is one of the most important parts of river engineering. Non-uniformity distribution of rainfall and various flow demand with unreasonable flow management will be caused destroyed of river ecosystem. Then, it is very serious to determine ecosystem flow requirement. In this paper, four hydrological based environmental flow assessment methods have been used to calculate environmental flow in Gharasou River, Ardabil, Iran as following: Flow duration curve indices method, Range of variability approach, Tessman method, and Global environmental flow calculator. In the first method, Q90 and Q95 for different return periods were calculated. Their magnitude were determined as 1-day, 3-day, 7-day and 30 day. Accordingthe second method, hydraulic alteration indices often had low and medium range. In order to maintain river at an acceptable ecological condition, July based flow was selected as environmental flow, i.e. 15 m3s-1. Using Tessman method, minimum and maximum values of monthly environmental flow was estimated 1.8 and 13.72 m3s-1, respectively. Based on the last method, seven scenarios were studied. Of all scenarios, scenario C indicates moderate situation of ecological habitat of river, according to calculations, the amount of the C scenario was determined as 6 m3s-1. Copyright © EM International. Source

Fuladipanah M.,Islamic Azad University at Ramhormoz | Jafarinia R.,Islamic Azad University of Arak
Ecology, Environment and Conservation | Year: 2014

River flow management requires discharge estimation. Unit hydrograph is an efficient method to flood hydrograph simulation. There are several models to create unit hydrograph. Clark model is one of the most widely used methods to produce unit hydrograph with its efficiency depending on the accuracy of estimation of storage coefficient and concentration time. In this the assessment of simulated unit hydrograph using Clark model has been investigated in Poledoab catchment, Iran. ARCGIS was used to evaluate physical properties of catchment in order to plot isochrones curves and time-area histogram. These curves were used to calculate storage coefficient and concentration time of catchment. The results showed that the Clark model has accepted simulation of peak time and peak discharge. Also, this model has accurate performance in large basins. Copyright © EM International. Source

Barati J.,Islamic Azad University at Ramhormoz | Mortazavi S.S.,Shahid Chamran University | Saidian A.,Shahid Chamran University
International Review of Electrical Engineering | Year: 2010

This paper investigates and compares the enhancement of damping the power system oscillations via coordinated design of the power system stabilizer (PSS), Thyristor Controlled Series Compensation (TCSC) and Static Var Compensator (SVC) controllers. The design problem of FACTS-based stabilizers is formulated as an optimization problem. The proposed approach employs genetic algorithm (GA) for stabilizer parameters optimization. In this paper eigenvalue analysis method is used for small signal stability of single machine infinite bus (SMIB) system installed with PSS, TCSC and SVC. The proposed stabilizers are tested on a weakly connected power system with loading conditions. The eigenvalue analysis and non-linear simulation results are presented and to show and compare the effects of these FACTS-based stabilizers and reveal that TCSC-based stabilizers is much better than SVC-based stabilizers on the damping power system oscillations. © 2010 Praise Worthy Prize S.r.l. - All rights reserved. Source

Abdi N.,Islamic Azad University at Ramhormoz | Fuladipanah M.,Islamic Azad University at Ramhormoz
Ecology, Environment and Conservation | Year: 2014

Sediment load estimation is one of the challenges of river engineering. More researches have been conducted to develop a perfect model to sediment transport simulation. Analytical and data-driven models are two main groups of models. In this paper, one dimensional fully coupled model and artificial neural network models performance is compared in sediment rating curve simulation in Ahwaz station, Karoonriver, Iran. 1D fully coupled model has calibrated and validated using Nash-Sutdiffe coefficient. The magnitude of 0.15 and 0.19 of NS coefficient for calibration and validation periods of coupled model represent good agreement of the model with average condition of river. According to calculation, derived sediment rating curve using ANN with FFBP algorithm, has good agreement with measured rating curve. In high flows, both two models have difference with measured data. In general ANN model has more accuracy than coupled model. Copyright © EM International. Source

Discover hidden collaborations