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Nikfahm A.,Petroleum University of Technology of Iran | Danaee I.,Petroleum University of Technology of Iran | Ashrafi A.,ShahidChamran University | Toroghinejad M.R.,Isfahan University of Technology
Materials Research | Year: 2013

The effect of changes in grain size on corrosion resistance of the pure tough pitch copper stripwas investigated in acidic and alkaline NaCl solutions. Accumulative roll bonding as sever plastic process was applied up to 8 cycles to produce the ultrafine graincopper. Polarization and electrochemical impedance tests were used for corrosion resistance investigations. Corrosion morphologies were analyzed by FE-SEM. Results showed that the corrosion resistance decreased up to cycle 2 and increased after rolled for the fourth time due to UFG grain formation after cycle 4. The corrosion degradation in cycle 8 was uniformand it was more intergranular for the sample of cycle 2 and the unrolled counterpart.

Igder S.,ShahidChamran University | Kiasat A.R.,ShahidChamran University | Shushizadeh M.R.,Ahvaz Jundishapur University of Medical Sciences
Research on Chemical Intermediates | Year: 2015

In this paper, the preparation and characterization of hydroxyapatite-encapsulated γ-Fe2O3 nanoparticles functionalized with Melamine nanocomposite (γ-Fe2O3@HAp@Melamine) are presented. The resulting nanocomposite was characterized by infrared spectroscopy, scanning electron microscope, thermal gravimetric analysis, X-ray diffraction, vibrating sample magnetometer and elemental analysis. The catalytic activity of γ-Fe2O3@ HAp@Melamine as a magnetic powerful basic nanocatalyst was probed through one-pot synthesis of 1, 4-dihydropyridine and polyhydroquinoline derivatives through Hantzsch condensation reaction under solvent-free thermal conditions. The heterogeneous catalyst could be recovered easily by simple magnetic decantation and reused many times without significant loss of its catalytic activity. © 2014 Springer Science+Business Media Dordrecht.

Fani R.,ShahidChamran University | Farshidi E.,ShahidChamran University
Circuits, Systems, and Signal Processing | Year: 2013

This paper presents a new fully differential second generation current controlled conveyor (FDCCCII) based on differential pair topology, which employs floating gate MOS transistors (FG-MOS). It uses floating gate MOSFETs at the input stage and has rail-to-rail structure which performs with both positive and negative signals. This circuit has tunable parasitic resistance at its input port. It operates with low supply voltage (±0.8 V), low power consumption (lower than 3 mW at current bias of 1 mA), and wide range parasitic resistance (R X ). This circuit has less MOSFET than the previous similar circuits and is suitable for integrated circuit design. To demonstrate the application of the proposed circuit, a fully differential current mode LC-ladder filter and a fully differential multifunction biquad filter are designed. Simulation results by HSPICE confirm validity of the proposed circuit and its application. © 2012 Springer Science+Business Media New York.

Aynehband A.,ShahidChamran University | Gerami F.,ShahidChamran University | Fateh E.,ShahidChamran University
Advances in Environmental Biology | Year: 2012

Utilization of green manure crops along with nitrogen fertilizer may balance requirement of soil and plants to nitrogen and increase nitrogen availability for succeeding crops. In order to study the effect of green manure (GM) crops and nitrogen (N) levels on grain, straw and soil nitrogen concentration and biomass production efficiency (BPE), a field experiment was conducted on Agricultural Faculty of ShahidChamran University of Ahvaz during 2010-2011. The experimental design was split plot based on RCB with three replications. Main plot including nitrogen rates (i. e. 0, 50, 100, 150 kg. ha -1) and sub-plot including green manure crops (i. e. fallow, millet, sesbania, amaranth, cowpea and mung bean). Our result showed that, both GM crops and N levels had significant effect on BPE, wheat grain, straw and soil N concentration. The effect of GM and N interaction was significant only on soil N concentration. Relationship BPE and wheat grain N concentration with N fertilizer levels was linear. In contrast, relationship of wheat straw N concentration as well as soil N concentration with N fertilizer levels was non-linear. Biomass production efficiency diminished as N fertilizer rates increased, while other studied factors increased with increase of N fertilizer rates. Highest grain and soil N concentration obtained with legume GM crops (sesbania and cowpea, respectively) application and highest BPE and straw N concentration obtained after fallow treatment. Generally, result of this study indicated that, legume GM crops can be better than non-legume GM crops due to atmospheric N fixation and release suitable nutrients especially N for subsequent crops.

Firouzi A.F.,ShahidChamran University | Babaei A.A.,Ahvaz Jundishapur University of Medical Sciences | Hosseini S.,ShahidChamran University | Heidarizadeh F.,ShahidChamran University
Fresenius Environmental Bulletin | Year: 2015

In the present study, sodium dodecyl sulphate-coated Fe3O4 (SDS-Mag) nanoparticles were prepared, characterized and applied to remove Cu(II) ions from aqueous solutions. Scanning Electron Microscopy measurements demonstrated that the particle size was about 40-60 nm. The results indicated that Cu(II) adsorption increased with increasing solution pH up to 5.0. Kinetic studies revealed that Cu(II) uptake was fast with 90% or more of the adsorption occurring within first 15 min of contact time. The adsorption of Cu(II) ions was relatively fast and the Avrami fractional order and pseudo-second-order kinetic models showed satisfactory fit with the experimental data. The equilibrium data were well fitted by the Liu isotherm model, with a maximum sorption capacity of 110.9 mg g-1. Desorption studies using an acidic eluent showed maximum recovery of adsorbent and sorption capacity was dropped only 9% after five cycles adsorption/desorption experiments.

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