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Taheri Otaqsara S.M.,Islamic Azad University at Majlesi
EPJ Applied Physics | Year: 2011

Use of microorganism as a novel and eco-friendly strategy to production of nanomaterials is an important aspect of modern nanotechnology. Biosynthesis of quasi-spherical silver nanoparticles (Ag-NPs) has been investigated using Pseudomonas aeruginosa. We observe that silver (Ag +) ions when exposed to P. aeruginosa biomass are reduced in solution, thereby leading to the formation of Ag-NPs. Quasi-spherical shape and nearly well distribution and FCC crystal structure of Ag-NPs were confirmed by XRD pattern, STM and TEM micrographs. UV-Vis spectra show a surface plasmon resonance (SPR) band at ~ 435 nm. © EDP Sciences, 2011. Source

Majdzadeh-Ardakani K.,Islamic Azad University at Majlesi | Nazari B.,Isfahan University of Technology
Composites Science and Technology | Year: 2010

Thermoplastic starch/poly(vinyl alcohol) (PVOH)/clay nanocomposites, exhibiting the intercalated and exfoliated structures, were prepared via melt extrusion method. The effects of clay cation, water, PVOH and clay contents on clay intercalation and mechanical properties of nanocomposites were investigated. The experiments were carried out according to the Taguchi experimental design method. Montmorillonite (MMT) with three types of cation or modifier (Na+, alkyl ammonium ion, and citric acid) was examined. The prepared nanocomposites with modified montmorillonite indicated a mechanical improvement in the properties in comparison with pristine MMT. It was also observed that increases in tensile strength and modulus would be attained for nanocomposite samples with 10%, 5% and 4% (by weight) of water, PVOH and clay loading, respectively. The clay intercalation was examined by X-ray diffraction (XRD) patterns. The chemical structure and morphology of the optimum sample was also probed by FTIR spectroscopy and transmission electron microscopy (TEM). © 2010 Elsevier Ltd. Source

Arezoomand M.,Islamic Azad University at Majlesi | Taeri B.,Isfahan University of Technology
Match | Year: 2013

In this paper the first and the second Zagreb indices of generalized hierarchical product of graphs, which is generalization of standard hierarchical and Cartesian product of graphs, is computed. As a consequence we compute the Zagreb indices of some chemical graphs. Source

Banitaba S.H.,Islamic Azad University at Majlesi | Safari J.,University of Kashan | Khalili S.D.,Islamic Azad University at Najafabad
Ultrasonics Sonochemistry | Year: 2013

A green and simple approach to assembling of 2-amino-4,8-dihydropyrano[3,2- b]pyran-3-carbonitrile scaffolds via three-component reaction of kojic acid, malononitrile, and aromatic aldehydes in aqueous media under ultrasound irradiation is described. The combinatorial synthesis was achieved for this methodology with applying ultrasound irradiation while making use of water as green solvent. In comparison to conventional methods, experimental simplicity, good functional group tolerance, excellent yields, short routine, and selectivity without the need for a transition metal or base catalyst are prominent features of this green procedure. © 2012 Elsevier B.V. All rights reserved. Source

Esfandiari E.,Islamic Azad University at Majlesi | Mariun N.B.,University Putra Malaysia
IEEE Transactions on Industrial Electronics | Year: 2013

This paper provides experimental results for a 2.5-kW 47-level prototype of the switch-ladder multilevel inverter including the following: input and output voltage and current waveforms under resistive and inductive loads, efficiency, total harmonic distortion, voltage stresses across the switches, behavior of the system under fault condition, and no-load power dissipation. The most important advantage of this inverter is that only four switches conduct in each interval in low frequency. This matter, beside the elimination of switching losses, has made this inverter an efficient choice with 97% peak efficiency. The ability to continue working with open-circuit modules is another advantage of the inverter. Furthermore, some important factors behind the unreliability and inefficiency of inverters have been improved, including the following: low duty cycle of conducting switches, staircase voltage stresses across switches with low-voltage steppes, line switching frequency results in low temperature of switches, possibility of removing low-pass filters, and independence to capacitors. The inverter is proposed to be an advantageous choice in low-voltage stand-alone photovoltaic applications. © 1982-2012 IEEE. Source

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