Tehran, Iran
Tehran, Iran

Shahed University , was founded in 1990. The university started its activities by accepting 165 students in seven branches in 1991. It has currently more than 8000 students in 68 branches. Today Shahed university has 8 colleges and 7 Research Institutions. Now, like other prominent universities of Iran,it is one of the first options chosen by applicants in the annual nationwide entrance exam. Shahed University is located in the capital city of Tehran. The main campus is located in the southern part of Tehran along the Persian gulf Freeway. Wikipedia.

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Rahmanifar M.S.,Shahed University
Electrochimica Acta | Year: 2017

Because of their commercial acceptability, Lead-Acid batteries are of significant importance, thus researchers constantly attempt to find new approaches to enhance their efficiency. In the present study, I sought to modify surface of the negative grids with aniline in sulfuric acid solution. Then, the modified grids were used as current collectors in negative plates of the cells in Lead-Acid batteries. The XRD, SEM, XPS, chronopotentiometry and cyclic voltammetry were employed for characterization of the modified grids, and constant current charge/discharge and electrochemical impedance spectroscopy techniques were used for studying the performance of the Lead-Acid cells. The results indicate that the growth of polyaniline fractal modifies the distance between the collector grids and active materials and the process of PbSO4 reduction to the metallic lead is enhanced on the modified lead grid. Although modification of the collector grids in negative plate seems to have no significant effect on the initial capacity of the cells, the grids modified with a 5 mM aniline solution shows a higher cumulative capacity after 90 complete charge/discharge cycles. XRD analysis on the negative active materials revealed a decrease in accumulation of the lead sulfate crystals on the negative plate. So, taking the decay in capacity to 35% of the initial amount as a criterion, cycle life of cells increased from 35 in the cells with commercial plates to >100 in the cells of the modified grids. Such a modification with three folds increment in battery life would help the Lead-Acid batteries to compete in the modern world. © 2017 Elsevier Ltd

Ghenaatian H.R.,Tarbiat Modares University | Mousavi M.F.,Tarbiat Modares University | Rahmanifar M.S.,Shahed University
Electrochimica Acta | Year: 2012

A hybrid asymmetric electrochemical supercapacitor is constructed by employing two different nanostructured conducting polymers of polypyrrole (PPy) and self-doped polyaniline (SDPA). Different electrochemical methods, including cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS), are performed to characterize the electrochemical performance of the supercapacitor. The maximal working potential window of 1.3 V is associated with more than 97 F g -1 of total electrode materials. The cell maintains approximately 70% of its initial capacitance after 1000 cycles with an equivalent series resistance (ESR) below 1.6 Ω cm 2. Furthermore, the system shows high specific energy, specific power and maximum power values of 22.87 Wh kg -1, 570 W kg -1 and 45,193 W kg -1, respectively, at a current density of 5 mA cm -2 in 1 M KCl. Long-life cycling is achieved by removing dissolved oxygen and using a mild pH electrolyte, which limits the redox activity of the electrically conducting polymers (ECPs). Moreover, the proposed supercapacitor exhibits high capacitance retention of 89% at a higher current density (40 mA cm -2), indicating good electrochemical stability and rate capability. The performance of the proposed hybrid supercapacitor has been compared with two other symmetric cells. © 2012 Elsevier Ltd.

Pendashteh A.,Tarbiat Modares University | Mousavi M.F.,Tarbiat Modares University | Rahmanifar M.S.,Shahed University
Electrochimica Acta | Year: 2013

Copper oxide (CuO) nanoparticles have been synthesized through a sonochemical assisted precipitation followed by thermal treatment. As prepared CuO nanoparticles have been anchored on surface of graphene oxide (GO) nanosheets through a simple electrostatic coprecipitation. Prepared samples have been characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray analysis (EDX). Morphology of the samples has been characterized by field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Symmetric supercapacitors have been assembled in real two-electrode configurations. Different symmetric configurations including CuO, GO, layer-by-layer coated CuO on GO network (GO/CuO), and composite (COMP) electrodes have been prepared. Their electrochemical behavior and supercapacitive performances have been investigated and compared with each other using various electrochemical methods including cyclic voltammetry, electrochemical impedance spectroscopy, and chronopotentiometric charge/discharge cycles. The composite material shows better electrochemical supercapacitive behavior and lower charge transfer resistance compared to other samples. It also shows better specific capacitance (245 F g-1) at current density of 0.1 A g-1 compared to the pure components (125 F g-1 for CuO and 120 F g-1 for GO) and the layer-by-layer coated electrodes (155 F g-1). Conducting charge/discharge measurements for 1000 cycles and in different current densities, it has been found that the composite material is a promising candidate for supercapacitor application, in terms of cycle ability and rate capability. © 2012 Elsevier Ltd. All rights reserved.

Miransari M.,Shahed University
Applied Microbiology and Biotechnology | Year: 2011

With respect to the adverse effects of chemical fertilization on the environment and their related expenses, especially when overused, alternative methods of fertilization have been suggested and tested. For example, the combined use of chemical fertilization with organic fertilization and/or biological fertilization is among such methods. It has been indicated that the use of organic fertilization with chemical fertilization is a suitable method of providing crop plants with adequate amount of nutrients, while environmentally and economically appropriate. In this article, the importance of soil microbes to the ecosystem is reviewed, with particular emphasis on the role of plant growth-promoting rhizobacteria, arbuscular mycorrhizal fungi, and endophytic bacteria in providing necessary nutrients for plant growth and yield production. Such microbes are beneficial to plant growth through colonizing plant roots and inducing mechanisms by which plant growth increases. Although there has been extensive research work regarding the use of microbes as a method of fertilizing plants, it is yet a question how the efficiency of such microbial fertilization to the plant can be determined and increased. In other words, how the right combination of chemical and biological fertilization can be determined. In this article, the most recent advances regarding the effects of microbial fertilization on plant growth and yield production in their combined use with chemical fertilization are reviewed. There are also some details related to the molecular mechanisms affecting the microbial performance and how the use of biological techniques may affect the efficiency of biological fertilization. © 2011 Springer-Verlag.

Omidi H.,Shahed University
American Journal of Plant Physiology | Year: 2010

The aim of present study was to get further information on the ability of drought stress applied to retard senescence and to frustrate inhibitory effects of drought-stress via comparing two canola genotypes differing in drought tolerance. The objective of this work was to evaluate the effects of the drought stress (control, -0.5, -1 and -1.5 Mpa) on two canola genotypes (Okapi and RGS). The experiment was factorial with four replications at experimental greenhouse at Center of Agriculture Research-Shahed, Iran, during 2006-2007. Morphological parameters of root and shoot dry weight, proline content osmolyte and enzyme activities of Ascorbate peroxidase (APx), Guaiacol peroxidase (GAx) and Catalase (Cat) in shoot and root of tissues canola genotypes were highly significant differences for main and interaction effects of two factors (Drought (D) and Genotype (G)) studied. Drought decreased the roots and shoots dry weight of canola plants and this effect was particularly significant at high level of stress. So, results indicated that proline content, ascorbate peroxidase (APx) and Guaiacol peroxidase (GAx) and Catalase (Cat) activity in root and shoot increased with enhancement of drought stress in the two genotypes. Of course, the proline content and antioxidant activities in Okapi genotype were more than RGS genotype. These results showed that Okapi genotype tolerated drought stress than RGS with increasing of proline content and antioxidant activities including GAx and APx. Shoot always maintained higher level of free Catalase (CAT) contents than the root. Therefore, the evaluation of both antioxidant enzymes and proline content can be suggested for Mechanisms of drought stress tolerance. © 2010 Academic Journals Inc.

Miransari M.,Shahed University
Biotechnology Advances | Year: 2011

Use of plants, with hyperaccumulating ability or in association with soil microbes including the symbiotic fungi, arbuscular mycorrhiza (AM), are among the most common biological methods of treating heavy metals in soil. Both hyperaccumulating plants and AM fungi have some unique abilities, which make them suitable to treat heavy metals. Hyperaccumulator plants have some genes, being expressed at the time of heavy metal pollution, and can accordingly localize high concentration of heavy metals to their tissues, without showing the toxicity symptoms. A key solution to the issue of heavy metal pollution may be the proper integration of hyperaccumulator plants and AM fungi. The interactions between the soil microbes and the host plant can also be important for the treatment of soils polluted with heavy metals. © 2011 Elsevier Inc.

Jalali-Nadoushan M.,Shahed University | Roghani M.,Shahed University
Brain Research | Year: 2013

Parkinson's disease (PD) is a progressive and debilitating neurodegenerative disorder for which current treatments afford symptomatic relief with no prevention of disease progression. Due to the neuroprotective and anti-apoptotic potential of alpha lipoic acid (LA), this study was undertaken to evaluate whether LA could improve behavioral and cellular abnormalities and markers of oxidative stress in an experimental model of early PD in rat. Unilateral intrastriatal 6-hydroxydopamine (6-OHDA)-lesioned rats were pretreated p.o. with LA at doses of 50 and/or 100 mg/kg twice at an interval of 24 h. After 1 week, apomorphine caused significant contralateral rotations, a significant reduction in the number of neurons was observed on the left side of the substantia nigra pars compacta (SNC), and malondialdehyde (MDA) and nitrite levels in midbrain homogenate significantly increased and activity of superoxide dismutase significantly reduced in the 6-OHDA group. LA pretreatment at a dose of 100 mg/kg significantly attenuated rotations, prevented loss of SNC neurons, and lowered levels of MDA and nitrite. These results suggest that LA could partially afford neuroprotection against 6-OHDA neurotoxicity that is in part due to the attenuation of oxidative stress burden and this may provide benefits, along with other therapies, in neurodegenerative disorders including PD. © 2013 Elsevier B.V.

The development of symbioses between soil fungi, arbuscular mycorrhizae (AM), and most terrestrial plants can be very beneficial to both partners and hence to the ecosystem. Among such beneficial effects, the alleviation of soil stresses by AM is of especial significance. It has been found that AM fungi can alleviate the unfavourable effects on plant growth of stresses such as heavy metals, soil compaction, salinity and drought. In this article, such mechanisms are reviewed, in the hope that this may result in more efficient use of AM under different stress conditions. © 2010 German Botanical Society and The Royal Botanical Society of the Netherlands.

Alizadeh R.,Shahed University
Safety Science | Year: 2011

A dynamic cellular automaton (CA) model is proposed to simulate the evacuation process in the rooms with obstacles. Besides the basic parameters such as human psychology, placement of the doors, doors width, position of the obstacles and light of the environment, distribution of the crowd plays an important role in this model. Applying our model, simulation of the evacuation process for a restaurant and a classroom are presented. Also effects of pedestrians distribution, doors position and doors width on the evacuation time are discussed and the obtained results are compared with several static models. © 2010 Elsevier Ltd.

Seyedtabaii S.,Shahed University
IET Generation, Transmission and Distribution | Year: 2012

A power line expert can easily pinpoint the type of fault that may have been occurred in a power transmission line. Transferring the experts intelligence to an artificial neural network (NN) makes the classification process fast and available online. Often the phase currents are used as NN inputs for this purpose. Lack of a somehow one-to-one relationship between the type of fault and the phases faulty currents prohibits the underlying network from being adequately trained. In a search for finding a type of feature that establishes a relatively unique link between the type of faults and the phase currents, it is noticed and mathematically proved that the ratios of the phase current jumps enjoy such a valuable advantage to be a prime choice as NN inputs. The inputs let a multi-layer perceptron (MLP) NN with about one node per phase to identify the faults accurately. The scheme works well in the presence of a various number of fault items. The superiority of the method is well realised when it is compared with the results of similar investigations using wavelet, fuzzy and others. The reference data are generated using MATLAB Power System Toolbox. The test samples are more general than those previously used in other investigations. © 2012 The Institution of Engineering and Technology.

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