فهرست مطالب m. mokari

In this paper, a novel risk-based, two-objective (technical and economical) optimal reactive power dispatch method in a wind-integrated power system is proposed which is more consistent with operational criteria.  The technical objective includes the minimization of the new voltage instability risk index. The economical objective includes cost minimization of reactive power generation and active power loss. The proposed voltage instability risk employs a hybrid possibilistic (Delphi-Fuzzy)-probabilistic approach that takes into consideration the operator’s experience, the wind speed and demand forecast uncertainties when quantifying the risk index. The decision variables are the reactive power resources of the system. To solve the problem, the modified multi-objective particle swarm optimization algorithm with sine and cosine acceleration coefficients is utilized. The method is implemented on the modified IEEE 30-bus system. The proposed method is compared with those in the previously published literature, and the results confirm that the proposed risk index is better at estimating the voltage instability risk of the system, especially in cases with severe impact and low probability. In addition, according to the simulation results compared to typical security-based planning, the proposed risk-based planning may increase the security and economy of the system due to better utilization of system resources.

In radiotherapy, ionizing radiation is used to damage cells. Monte Carlo simulations of radiation interactions with DNA give us good information about the type of damage and their repair process, which can be very useful in treating cancer and protecting against radiation. The ionizing radiation damage includes single- and double-strand breaks as well as base lesions (SSB, DSB, BL). The DNA damage can be repaired through some processes within the cell. DNA damage, especially of DSBs that are mis-repaired or unrepaired, can result in cell death. This process plays a crucial role in killing cancer cells and treating cancer. In this research, first, the dose was calculated in the cell nucleus with the MCNPX code. Then, the possibility of different damage types in DNA was investigated by simulating the physical and chemical processes of low and high-energy electrons with the Geant4-DNA code. Then with the help of the Matlab software and mathematical modeling, we investigated the repair of DSBs for the latter energies. The results show that at ranging energies of 100 to 300 eV, the number of breaks increases, and for higher energies, it decreases due to the electron range in the cell nucleus. The repair reaction rate is also calculated from the NHEJ presynaptic process for ranging energies 100 eV to 1 MeV. In the repair section, the repair time at low energies is longer than the higher energies due to more DSBs.

Optimal use of water resources seem to be necessary due to climate change and the recent drought conditions. One of the most important and effective management strategies is increasing water productivity in agriculture. Irrigation method and the use of different levels of nitrogen fertilizer are the effective factors in increasing the water productivity. Therefore, this study was conducted to investigate the effect of the irrigation method and nitrogen fertilizer on the harvest index and water productivity of two wheat cultivars with 36 treatments as a split-split plot based on a completely randomized design with three replications in the research farm of Natural Resources and Agricultural Research Center of Kashmar, during the 2018-2019 time period. The treatments were two irrigation methods including end blocked border and drip irrigation (tape) as  the main plots, three levels of the nitrogen fertilizer from urea source including 0, 50 and 100 kg/ha as the  sub plots and two cultivars of wheat including Pishgam and Sirvan as the sub-sub plots. The results showed that by changing the border irrigation method to the drip irrigation (tape) method, the harvest index and water productivity were increasesignificantly. The results also showed that grain yield and its components, including harvest index and water productivity, had no significant difference in 50 and 100 kg/ha nitrogen levels. On the other hand, grain yield and its components, harvest index and water productivity, were significantly higher in the Sirvan cultivar rather than the Pishgam one (P<0.01). According to the results obtained from this study, the drip irrigation method, 50 kg/ha nitrogen level and Sirvan cultivar could be recommended for the study region.

The interaction of ionizing radiations with living tissues could result in simple and complex single- and double-strand breaks in the cell DNAs, due to the physical and chemical processes that such radiations initiate. Monte Carlo simulation of the interaction between radiations and DNA renders valuable information about damage types, which can be very useful in cancer therapy and radiation protection. In this study, in order to calculate the initial DNA damage caused by the primary electron beam and the produced secondary particles, Geant4-DNA has been employed to simulate the physical, physico-chemical, and chemical interactions. Using the simulation results for the direct electron interactions and indirect hydroxyl radical reactions with the DNA, the probability of different types of breaks in the cell DNAs as well as the distribution of the breaks as a function of the deposited energy have been investigated.

In order to investigate the effect of new deficit irrigation strategies on the quantitative characteristics and water productivity of two field grown corn cultivars, a split plot experiment was conducted as a randomized design in three replications. The irrigation treatments included full irrigation treatment (FI), static deficit irrigation (SDI), dynamic deficit irrigation (DDI), static partial root zone drying irrigation (SPRD), which received 75% of ET during the growth period, dynamic partial root zone drying irrigation (DPRD), which received 90% of ET in the first one- third of the growth period, 75% of ET in the second one- third of growth period, and 50% of ET in the last one- third of the growth period. The results showed that there were significant differences between irrigation strategies. The SDI, DDI, SPRD and DPRD irrigation treatments decreased the corn yield by 18%, 27%, 49% and 53%, as compared to FI, respectively. The results also showed that there were no significant differences between cultivars. Compared to FI, the SDI increased WP by 14%, but DDI, SPRD and DPRD decreased WP by 3%, 19% and 44%, respectively. According to economic analysis, irrigation optimum depth for the maximum net profit was obtained to be 858.5 mm. In general, the SDI strategy is recommended in the study area.

In this article, by using the method of finite difference time domain (FDTD) and PML boundary conditions, we have studied the photonic band gaps for TE and TM modes in square and triangular lattices consisting of air holes in dielectric medium and compared the results. In addition, the effect of nonlinearity of the photonic crystal background on the photonic band gaps and comparison with the results of the linear case (holes in a background medium with linear dielectric constant) has been presented. Comparison of the transmission spectrums in linear and nonlinear cases shows a red shift in minimum transmission for both triangular and square lattices.

Remote sensing is a suitable method for estimating of actual evapotranspiration (AET) especially in large scales. As the estimation of AET with both high temporal and spatial resolution is impossible for most sensors such as MODIS and Landsat, it is necessary that the AET maps derived from a sensor were downscaled to another sensor using downscaling methods. The objectives of this study were to use of different scaling factors simultaneously for input parameters of SEBAL included surface albedo, normalized difference vegetation index (NDVI) and land surface temperature (LST) for spatial downscaling of AET maps derived based-MODIS (1000 m) images to Landsat images (30 m) and also temporal downscaling of AET maps derived based Landsat (16 day) images to MODIS (daily) images using input/output regression and input/output subtraction methods in a part of Mashhad plain. The results showed that the zero band emissivity of Landsat and LST of MODIS images had the best performance in spatial downscaling of AET maps. NDVI and LST of Landsat images as a scaling factor had not a good performance in spatial downscaling of AET maps in summer and spring, respectively. Considering the results of this study, it can be concluded that the zero band emissivity of Landsat and LST of MODIS images as a scaling factor for spatial downscaling of AET maps and input regression method for temporal downscaling of AET maps are suitable in Mashhad plain.

Actual evapotranspiration (ETa) estimation is a main factor for irrigation scheduling, hydrological balance, design and management of irrigation systems and crop yield prediction. Therefore many researchers have been tried to achieve ETa in different spatial and temporal scales. Remote sensing is one of the newest methods that can be used for this purpose. Therefore, In present study, spatial distribution of daily Eta at a part of Mashhad plain was estimated using Landsat 8 satellite images on 9 June, 25 June, 28 August and 13 September 2013. For this purpose, soil adjusted vegetation index (SAVI) was optimized for SEBAL algorithm. The results showed that there was a correlation between normalized difference vegetation index (NDVI) and ETa in study events. Also, standard deviation of SAVI was the least for L=1 (correction factor of soil background effects). Therefore it can be concluded that optimum amount of L for study region is one. Also the trend of ETr was similar to ETa. It can be concluded that plant cover in agriculture lands had no limitation for accessible of water in study region.