Ghaedi M.,Yasouj University |
Heidarpour S.,Payame Noor University |
Nasiri Kokhdan S.,Islamic Azad University at Yasuj |
Sahraie R.,Ilam University |
And 2 more authors.
Powder Technology | Year: 2012
The objective of this study was to assess and compare the usability of silver and palladium nanoparticles loaded on activated carbon (Ag NPs-AC and/or Pd NPs-AC) for the removal of Methylene blue (MB) molecules from aqueous solutions. Following the optimization of the effect of variables (batch method) including pH, contact time, initial dye concentration and Ag NPs-AC and Pd NPs-AC amounts on MB removal method the kinetic and isotherm studies have been carried out. Based on difference in MB contents (using a UV-vis spectrophotometer) before and after MB adsorption the removal percentage was calculated. The sorption processes followed the pseudo-second-order in addition to intraparticle diffusion kinetic models with good correlation coefficient. The equilibrium experimental data well fitted to the Langmuir models with maximum adsorption capacity of 71.4 and 75.4. mg/g for Ag NPs-AC and Pd NPs-AC, respectively. The obtained results showed that both adsorbents due to their high MB adsorption capacity in short equilibrium times are good alternative as low-cost sorbent in wastewater treatments. © 2012.
Ghaedi M.,Yasouj University |
Shokrollahi A.,Yasouj University |
Hossainian H.,Yasouj University |
Kokhdan S.N.,Islamic Azad University at Yasuj
Journal of Chemical and Engineering Data | Year: 2011
The objective of this study was to assess the suitability and efficiency of activated carbon (AC) and multiwalled carbon nanotube (MWCNT) for the removal of Eriochrome Cyanine R (ECR) molecules from aqueous solutions. The effect of different variables in the batch method as a function of solution pH, contact time, initial dye concentration, AC and MWCNT amount, temperature, electrolyte, and so forth by the optimization method has been investigated. ECR contents were determined using a UV-vis spectrophotometer before and after ECR adsorption on the AC and MWCNT, and the removal percentage was calculated using the difference in absorbance. The sorption processes followed the pseudosecond order in addition to intraparticle diffusion kinetics models with a good correlation coefficient with the overall entire adsorption of ECR on both adsorbents. Equilibrium data fit well with the Langmuir and Tempkin models with a maximum adsorption capacity based on the Langmuir equation of (40.6 and 95.2) mg·g-1 for AC and MWCNT, respectively. Thermodynamic parameters such as change in enthalpy (δH°) and entropy (δS°), activation energy (Ea), sticking probability (S*), and Gibbs free energy changes (δG°) were also calculated. Judgment based on the obtained results of thermodynamic values shows the spontaneous and endothermic nature adsorption processes on both adsorbents. © 2011 American Chemical Society.
Azizi S.,Islamic Azad University at Yasuj |
Ahmadloo E.,Islamic Azad University at Darab
Applied Thermal Engineering | Year: 2016
An artificial neural network model was developed to predict convective heat transfer coefficient (HTC) during condensation of R134a in an inclined smooth tube for the entire range of inclination angles at different saturation temperatures and regardless of flow pattern. The network was designed and trained using a total of 440 experimental data points collected from the literature. Inclination angle, mass flux, saturation temperature and mean vapor quality were used as input variables of multiple layer perceptron (MLP) neural network, while the corresponding HTC was selected as its output variable. By trial-and-error method, MLP network with 18 neurons in the hidden layer was achieved as optimal structure of the ANN which made it possible to predict the HTC with a high accuracy. Mean absolute percent error (MAPE) of 1.48% and correlation coefficient (R) of 0.997 for training data and MAPE of 1.94% and R value of 0.995 for testing data were obtained. Also, 95% and 99% all data were within ±5% and ±7% error band, respectively. MAPE of 1.61% and R value of 0.9963 were calculated for all data. These results confirm the high ability of the ANNs for predicting the HTC values for the entire range of inclination angles and independent of the flow pattern. © 2016 Elsevier Ltd
Marahel F.,Islamic Azad University |
Ghaedi M.,Islamic Azad University |
Nasiri Kokhdan S.,Islamic Azad University at Yasuj
Fresenius Environmental Bulletin | Year: 2012
In this research adsorption and removal of Sudan red 7B (SR7B) from aqueous solution using silver nanoparticle loaded on activated carbon (Ag-NP-AC) has been investigated. Equilibrium data are mathematically modeled using the Freundlich Langmuir, Tempkin and Dubinin-Radushkevich (D-R) adsorption models. The SR7B adsorption kinetics on to Ag-NP-AC was studied in terms of pseudo-first-order, pseudo-second-order, Intraparticle diffusion and Elovich models. A maximum adsorption capacity of 90.909 mg.g -1 based on Langmuir as most applicable model at equilibrium is achieved. The high capacity and low removal time show the suitability and usefulness of Ag-NP-AC alternative adsorbent for the removal of SR7B in wastewater treatment. © PSP Volume 21 - No 1a.2012.
Ghaedi M.,Yasouj University |
Kokhdan S.N.,Islamic Azad University at Yasuj
Desalination and Water Treatment | Year: 2012
Oxidized multiwalled carbon nanotubes (MWCNT) were used for the removal of methyl red (MR) from aqueous solutions. The effects of variables, such as initial solution pH, initial dye concentration, temperature, and sorption time, on MR removal were studied and optimized. Fitting the experimental equilibrium data to various investigated isotherm models, such as Langmuir, Freundlich, Tempkin, and Dubinin-Radushkevich (D-R) models, showed the suitability of the Langmuir model with the highest correlation coefficients. The calculated thermodynamic parameters indicated that the removal of MR by MWCNT is an entropy-driven and endothermic process. The experimental data were analyzed by different kinetic models, such as pseudo-first order, pseudo-second order, and Elovich and intraparticle diffusion models. It was found that the second-order equation and intraparticle diffusion models are the rate-limiting factor and control the kinetic of the adsorption process. © 2012 Desalination Publications. All rights reserved.
Naderi M.,Khorramshahr Marine Science and Technology University |
Wong M.Y.L.,University of Wollongong |
Gholami F.,Islamic Azad University at Yasuj
Aquatic Toxicology | Year: 2014
In the recent years, there has been a growing concern about the production and use of bisphenol-A substitute, namely bisphenol-S (BPS). Due to its novel nature, there have been few studies addressing the ability of BPS to disrupt the endocrine system of animals. In the present study, zebrafish (Danio rerio) embryos were exposed to and reared in various concentrations of BPS (0, 0.1, 1, 10 and 100. μg/l) for 75 days. Then adult males and females were paired in spawning tanks for 7 days in clean water and the consequent effects on fish development, reproduction, plasma vitellogenin (VTG), sex steroids and thyroid hormone levels were investigated as endpoints. After 75 days of exposure, there was a skewed sex ratio in favor of females. The results also showed that body length and weight significantly decreased in males exposed to 100. μg/l of BPS. Gonadosomatic index was significantly reduced in fish at ≥10. μg/l. Hepatosomatic index exhibited a significant increase in both male and female fish. At ≥1. μg/l of BPS, plasma 17β-estradiol levels were significantly increased in both males and females. However, plasma testosterone showed a significant reduction in males exposed to 10 and 100. μg/l of BPS. A significant induction in plasma VTG level was observed in both males and females at ≥10. μg/l of BPS. Plasma thyroxine and triiodothyronine levels were significantly decreased at 10 and 100. μg/l of BPS in males, and at 100. μg/l in females. Egg production and sperm count were also significantly decreased in groups received 10 and 100. μg/l of BPS. Moreover, once time to hatching and hatching rates were calculated for fertilized eggs the postponed and decreased rates of hatching were observed. Taken together, these results suggest that developmental exposure to low concentrations of BPS has adverse effects on different parts of the endocrine system in zebrafish. © 2014.
Ghaedi M.,Yasouj University |
Tavallali H.,Payame Noor University |
Sharifi M.,Payame Noor University |
Kokhdan S.N.,Islamic Azad University at Yasuj |
Asghari A.,Semnan University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2012
In this research, the potential applicability of activated carbon prepared from Myrtus communis (AC-MC) and pomegranate (AC-PG) as useful adsorbents for the removal of Congo red (CR) from aqueous solutions in batch method was investigated. The effects of pH, contact time, agitation time and amount of adsorbents on removal percentage of Congo red on both adsorbents were examined. Increase in pH up to 6 for AC-MC and pH 7 for AC-PG increase the adsorption percentage (capacity) and reach equilibrium within 30 min of contact time. Fitting the experimental data to conventional isotherm models like Freundlich, Langmuir, Tempkin and Dubinin-Radushkevich show that the experimental data fitted very well to the Freundlich isotherm for AC-MC and Langmuir isotherm for AC-PG. Fitting the experimental data to different kinetic models such as pseudo first-order, pseudo second-order, Elovich and intraparticle diffusion mechanism showed the applicability of a pseudo second-order with involvement of intraparticle diffusion model for interpretation of experimental data for both adsorbents. The adsorption capacity of AC-PG and AC-MC for the removal of CR was found to be 19.231 and 10 mg g -1. These results clearly indicate the efficiency of adsorbents as a low cost adsorbent for treatment of wastewater containing CR. © 2011 Elsevier B.V. All rights reserved.
Taher S.A.,University of Kashan |
Malekpour M.,Islamic Azad University at Yasuj
Mathematical Problems in Engineering | Year: 2011
In this article, a new fault detection technique is proposed for squirrel cage induction motor (SCIM) based on detection of rotor bar failure. This type of fault detection is commonly carried out, while motor continues to work at a steady-state regime. Recently, several methods have been presented for rotor bar failure detection based on evaluation of the start-up transient current. The proposed method here is capable of fault detection immediately after bar breakage, where a three-phase SCIM is modelled in finite element method (FEM) using Maxwell2D software. Broken rotor bars are then modelled by the corresponding outer rotor impedance obtained by GA, thereby presenting an analogue model extracted from FEM to be simulated in a flexible environment such as MATLAB/SIMULINK. To improve the failure recognition, the stator current signal was analysed using discrete wavelet transform (DWT). © 2011 Seyed Abbas Taher and Majid Malekpour.
Rezaei G.,Yasouj University |
Vaseghi B.,Yasouj University |
Doostimotlagh N.A.,Islamic Azad University at Yasuj
Communications in Theoretical Physics | Year: 2012
Simultaneous effects of an on-center hydrogenic impurity and band edge non-parabolicity on intersubband optical absorption coefficients and refractive index changes of a typical GaAs/Al xGa 1-x As spherical quantum dot are theoretically investigated, using the Luttinger - Kohn effective mass equation. So, electronic structure and optical properties of the system are studied by means of the matrix diagonalization technique and compact density matrix approach, respectively. Finally, effects of an impurity, band edge non-parabolicity, incident light intensity and the dot size on the linear, the third-order nonlinear and the total optical absorption coefficients and refractive index changes are investigated. Our results indicate that, the magnitudes of these optical quantities increase and their peaks shift to higher energies as the influences of the impurity and the band edge non-parabolicity are considered. Moreover, incident light intensity and the dot size have considerable effects on the optical absorption coefficients and refractive index changes. © 2012 Chinese Physical Society and IOP Publishing Ltd.
Namazian Z.,Islamic Azad University at Yasuj
International Journal of Mechanical and Mechatronics Engineering | Year: 2016
This study examines a new device aimed at reducing drag on commercial vehicles. The computational fluid dynamics (CFD) technique is utilized to the analysis of air flow around this device and also to optimize the geometry of device that has important effect on drag reduction. At first, simplified dimensions of a commercial vehicle are modeled as demonstrated in literature and the coefficient of the drag is measured through the analysis of the fluid flow. After choosing various different geometries with the addition of the new device and picking out the best geometry, the coefficient of the drag in the new position is measured and a comparison is made with the base model. The results indicate that there is about 22% drag reduction in the new state in comparison to the base model. © February 2016 IJENS.