A study of a polymeric membrane performance in an ultrafiltration system to use in industrial application

, Article Desalination and Water Treatment ; Volume 53, Issue 2 , Sep , 2015 , Pages 340-351 ; 19443994 (ISSN) Reyhani, A ; Rajaei, F ; Shahmoradi, M ; Kahkesh, A ; Sharif University of Technology

Taylor and Francis Inc 2015

Abstract

The performance of a polymeric membrane in an ultrafiltration system under the chosen optimum conditions was studied. To achieve this, four real produced waters were dealt with. To find the optimum conditions, Taguchi method was applied. Results showed that PAN350 membrane is a potential candidate for industrial applications for three feeds which contained oil and total organic carbon (TOC) less than 1,500 and 300 ppm, respectively. The values of oil/grease, total suspended solids, and turbidity rejections were approximately 100%. Although TOC could not be entirely removed, the removal values for TOC were acceptable in this study. For the fourth feed due to the values of oil and TOC which...

Optimization of conditions in ultrafiltration treatment of produced water by polymeric membrane using Taguchi approach

, Article Desalination and Water Treatment ; Volume 51, Issue 40-42 , 2013 , Pages 7499-7508 ; 19443994 (ISSN) Reyhani, A ; Rekabdar, F ; Hemmati, M ; SafeKordi, A. A ; Ahmadi, M ; Sharif University of Technology

Desalination Publications 2013

Abstract

In this study, the ultrafiltration of produced water was studied using a two-stage ultrafiltration process. In the first stage, the influences of operating parameters, including transmembrane pressure, temperature, and cross-flow velocity on the amount of flux decline caused by membrane fouling, were investigated using a polymeric membrane. In order to design the experiments and optimize the experimental results, the Taguchi method was applied. L9 (33) orthogonal array for experimental planning and the smaller-the-better response category was selected to obtain optimum conditions because the lowest flux decline was our aim. Analysis of variance was used to determine the most important...

A study on the effects of Fex/Niy/MgO(1-x-y) catalysts on the volumetric and electrochemical hydrogen storage of multi-walled carbon nanotubes

, Article International Journal of Hydrogen Energy ; Volume 35, Issue 1 , 2010 , Pages 231-237 ; 03603199 (ISSN) Reyhani, A ; Mortazavi, S. Z ; Zaker Moshfegh, A ; Nozad Golikand, A ; Sharif University of Technology

2010

Abstract

The effects of various ratios of Fe/Ni/MgO and growth temperatures on yield, diameter and quality of multi-walled carbon nanotubes (MWCNTs) were studied. Thermal gravimetric analysis (TGA) confirmed that the MWCNT yield depends on Fe/Ni ratio with the following order; Fe0.5 Ni0.5 > Fe > Fe0.75 Ni0.25 > Fe0.25 Ni0.75 > Ni. The results indicated that there is an optimum temperature (940 °C) for the MWCNT growth both from quality and quantity (yield) aspects as compared to other temperatures. Moreover, the changes on Fe/Ni to MgO ratio for the MWCNT growth revealed that Fe/Ni/MgO with the ratio of 17.5/17.5/65 had the highest quality and surface area as compared to the other ratios. The...

The effect of oxidation of macroporous silicon on carbon nanotubes growth by TCVD method

, Article Synthesis and Reactivity in Inorganic, Metal-Organic and Nano-Metal Chemistry ; Volume 37, Issue 6 , 2007 , Pages 489-492 ; 15533174 (ISSN) Mortazavi, S. Z ; Iraji zad, A ; Taghavi, N. S ; Reyhani, A ; Sharif University of Technology

2007

Abstract

Carbon nanotubes (CNTs) were grown on deposited Ni on macroporous silicon by thermal chemical vapor deposition (TCVD) method using CH4 as the reaction gas. Macroporous silicon was fabricated by electrochemical etching of P-type silicon in organic electrolytes. The effect of oxidation of porous silicon (PS) on growth rate, morphology and structure of CNTs has been studied. The SEM micrographs and Raman spectra indicated that the nanotubes grown on the oxidized PS are more homogeneous and regular than those grown on the pristine PS and growth rate of CNTs grown on oxidized PS higher than those grown on pristine PS. In addition, the CNTs grown on the non-oxidized PS have different morphology...

Efficient and concurrent reliable realization of the secure cryptographic SHA-3 algorithm

, Article IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems ; Vol. 33, issue. 7 , July , 2014 , p. 1105-1109 ; 0278-0070 Bayat-Sarmadi, S ; Mozaffari-Kermani, M ; Reyhani-Masoleh, A ; Sharif University of Technology

2014

Abstract

The secure hash algorithm (SHA)-3 has been selected in 2012 and will be used to provide security to any application which requires hashing, pseudo-random number generation, and integrity checking. This algorithm has been selected based on various benchmarks such as security, performance, and complexity. In this paper, in order to provide reliable architectures for this algorithm, an efficient concurrent error detection scheme for the selected SHA-3 algorithm, i.e., Keccak, is proposed. To the best of our knowledge, effective countermeasures for potential reliability issues in the hardware implementations of this algorithm have not been presented to date. In proposing the error detection...

Experimental Investigation of Response of Counter Flow Flames to Acoustic Excitations

, M.Sc. Thesis Sharif University of Technology Reyhani, Mohammad (Author) ; Farshchi, Mohammad (Supervisor)

Abstract

The primary purpose of the present thesis is to understand the dynamic behavior of partially premixed flames of counterflow burners. In this project, work has been done on the previously designed and built counterflow burner. By setting up partially premixed flames in this burner, acoustic excitation of these flames has been done, and finally data acquisition by taking video of the flame and then using image processing to extract the dynamic response of these flames. The flames that we have examined in this project are all in a laminar regime and the fuel used in these flames is also natural gas. The frequencies that we have examined in these flames are 25 and 40 Hz, and these tests were...

Implementation of Local Chemiluminescence Method on Flame

, M.Sc. Thesis Sharif University of Technology Reyhani, Anahita (Author) ; Kebriaei, Azadeh (Supervisor)

Abstract

In the present work, the local Chemiluminescence method has been implemented on a laminar premixed propane-air flame. The goal of this work is to achieve a system capable of measuring the intensity of Chemiluminescent radiations of CH* and OH* radicals locally and with high spatial and temporal accuracy. For this purpose, a setup has been designed and developed. In order to achieve high spatial accuracy for local measurements, a Cassegrain lens has been designed and built, which has the ability to collect light from a cylindrical control volume with a cross-sectional diameter of 58 μm and a depth of 3.4 mm. An optical system for dividing and filtering light based on wavelength has also been...

Chemo-physical properties of renal capsules under ultraviolet-c exposure

, Article Journal of Applied Physics ; Vol. 116, Issue. 5 , 2014 ; ISSN: 00218979 Baghapour, Sh ; Parvin, P ; Reyhani, A ; Mortazavi, S. Z ; Mokhtari, S ; Amjadi, A ; Sharif University of Technology

2014

Abstract

The renal capsule tissue of lamb was irradiated with ultraviolet-C light and the treated samples were analyzed by uniaxial tensile test, dynamic mechanical analysis, attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and contact angle measurements. It was shown that the skin cross-linking is dominant in low doses in accordance with the contact angle assessment. Conversely, the strong bulk degradation takes place at high doses. Similarly, the bulk cross-linking affects the mechanical tests as to enhance the stiffness at low doses, whereas strong degradation occurs at high doses that mainly arises from the strong bulk chain scission

H 2 adsorption mechanism in Mg modified multi-walled carbon nanotubes for hydrogen storage

, Article International Journal of Hydrogen Energy ; Volume 37, Issue 2 , January , 2012 , Pages 1919-1926 ; 03603199 (ISSN) Reyhani, A ; Mortazavi, S. Z ; Mirershadi, S ; Golikand, A. N ; Moshfegh, A. Z ; Sharif University of Technology

2012

Abstract

Multi-walled carbon nanotubes (MWCNTs) with diameter of about 50 nm were synthesized using thermal chemical vapor deposition. We have investigated the influence of Mg doping to the MWCNTs on its hydrogen storage property. TEM micrographs showed that Mg was attached to the MWCNTs and discontinuous arrangement of the carbon walls was recognized in the MWCNTs. According to XPS and BET analyses, the surface functional groups and pore size of the Mg-MWCNTs are increased by interactions between the Mg and the MWCNT's outer walls. The electrochemical discharging curves of the MWCNTs and Mg-doped MWCNTs revealed that the hydrogen storage capacity was 363 and 450 mAhg -1, respectively. Volumetric...

The effects of multi-walled carbon nanotubes graphitization treated with different atmospheres and electrolyte temperatures on electrochemical hydrogen storage

, Article Electrochimica Acta ; Volume 55, Issue 16 , June , 2010 , Pages 4700-4705 ; 00134686 (ISSN) Reyhani, A ; Nozad Golikand, A ; Mortazavi, S. Z ; Irannejad, L ; Moshfegh, A. Z ; Sharif University of Technology

2010

Abstract

Using multi-walled carbon nanotubes (MWCNTs), the present study focuses on their electrochemical hydrogen storage capacities. The results showed that the hydrogen desorption process is composed of two steps with voltages around -0.75 and -0.15 V. Hydrogen adsorption at -0.15 V took place at temperatures above 30 °C, and the amount of energy required for adsorbing hydrogen was 1.68 eV. The hydrogen storage capacity increased with increasing electrolyte temperature from 30 to 60 °C in both steps. The hydrogen storage capacity of the MWCNTs treated at different atmospheres showed that the decrease in the graphitization of MWCNTs led to the increase in hydrogen adsorption. The results also...

Physical and chemical properties of lamb renal capsule irradiated by ArF laser

, Article Journal of Laser Applications ; Volume 27, Issue 1 , 2015 ; 1042346X (ISSN) Mokhtari, S ; Parvin, P ; Reyhani, A ; Mortazavi, S. Z ; Baghapour, Sh ; Amjadi, A ; Sharif University of Technology

2015

Abstract

Excimer laser at 193 nm was irradiated on the renal tissues during various exposure times in order to investigate the chemical and physical surface properties using Fourier transform infrared spectroscopy, photo electron spectroscopy, contact angle measurements, and tensile test accordingly. We have shown that ultraviolet laser strongly alters the oxygen content of skin layer that causes changes in the tissue morphology leading to significant skin hydrophilicity

The effect of various acids treatment on the purification and electrochemical hydrogen storage of multi-walled carbon nanotubes

, Article Journal of Power Sources ; Volume 183, Issue 2 , 1 September , 2008 , Pages 539-543 ; 03787753 (ISSN) Reyhani, A ; Mortazavi, S. Z ; Nozad Golikand, A ; Moshfegh, A. Z ; Mirershadi, S ; Sharif University of Technology

Elsevier 2008

Abstract

The effects of HCl, HNO3, H2SO4 and HF acids on the purification and the electrochemical hydrogen storage of multi-walled carbon nanotubes (MWCNTs) were studied. The MWCNTs were synthesized on Fe-Ni catalyst by thermal chemical vapor deposition method. The X-ray diffraction and thermal gravimetric analysis results indicated that the MWCNTs purified by HF acid had the highest impurities as compared with the other acids. The N2 adsorption results at 77 K indicated that all the samples were mainly mesoporous and the purified MWCNTs by HF acid had the highest surface area as compared with the other acids. The hydrogen storage capacities of the purified MWCNTs by the following acids were in...

Effect of Ni, Pd and Ni-Pd nano-islands on morphology and structure of multi-wall carbon nanotubes

, Article Applied Surface Science ; Volume 253, Issue 20 , 2007 , Pages 8458-8462 ; 01694332 (ISSN) Reyhani, A ; Mortazavi, Z ; Akhavan, O ; Moshfegh, A. Z ; Lahooti, Sh ; Sharif University of Technology

Elsevier 2007

Abstract

In this research, the effect of Ni, Pd and Ni-Pd catalysts have studied on morphology and structure of synthesized multi-wall carbon nanotubes (MWCNTs). Initially, thin films of Ni (with two thicknesses of 10 and 20 nm), Pd/Ni (5/10 nm) and Pd (10 nm) were deposited as catalysts on SiO 2 (60 nm)/Si(1 0 0) substrates, using dc magnetron sputtering technique. The deposited films were annealed at 900 °C in ammonia environment for 45 min, in order to obtain nano-structured catalyst on the surface. Using scanning electron microscopy (SEM), the average size of Ni nano-islands (synthesized by the 10 and 20 nm Ni films), Pd and Ni-Pd nano-islands were measured about 55, 110, 45 and 50 nm,...

Optimal operating conditions of micro- and ultra-filtration systems for produced-water purification: Taguchi method and economic investigation

, Article Desalination and Water Treatment ; Volume 57, Issue 42 , 2016 , Pages 19642-19654 ; 19443994 (ISSN) Reyhani, A ; Mashhadi Meighani, H ; Sharif University of Technology

Taylor and Francis Inc 2016

Abstract

In this study, treatment of two real produced waters was studied using microfiltration (MF) and ultrafiltration. In the first step, the effects of operating parameters including temperature, transmembrane pressure (TMP), cross-flow velocity (CFV), and back pulse time (BPT) (in the MF system) at three levels on the amount of permeate flux were investigated using ceramic and polymeric membranes. To design the experiments and optimize the experimental results, the L9 (34) and L9 (33) orthogonal arrays of the Taguchi method and a response category of the-larger-the-better were applied. Analysis of variance was used to determine the most important parameters affecting the permeate flux. The...

Optimal operating conditions of micro- and ultra-filtration systems for produced-water purification: Taguchi method and economic investigation

, Article Desalination and Water Treatment ; Volume 57, Issue 42 , Oct , 2015 , Page 19642-19654 ; 19443994 (ISSN) Reyhani, A ; Mashhadi Meighani, H ; Sharif University of Technology

Taylor and Francis Inc 2015

Abstract

In this study, treatment of two real produced waters was studied using microfiltration (MF) and ultrafiltration. In the first step, the effects of operating parameters including temperature, transmembrane pressure (TMP), cross-flow velocity (CFV), and back pulse time (BPT) (in the MF system) at three levels on the amount of permeate flux were investigated using ceramic and polymeric membranes. To design the experiments and optimize the experimental results, the L9 (34) and L9 (33) orthogonal arrays of the Taguchi method and a response category of the-larger-the-better were applied. Analysis of variance was used to determine the most important parameters affecting the permeate flux. The...

Optimization of operating conditions in ultrafiltration process for produced water treatment via Taguchi methodology

, Article Desalination and Water Treatment ; Volume 54, Issue 10 , June , 2015 ; ISSN: 19443994 Reyhani, A ; Sepehrinia, K ; Seyed Shahabadi, S. M ; Rekabdar, F ; Gheshlaghi, A ; Sharif University of Technology

2015

Abstract

This paper describes how to find optimal operating conditions of three controlling parameters, i.e. temperature, transmembrane pressure (TMP), and cross-flow velocity (CFV) for maximizing the permeate flux and total organic carbons (TOC) rejection, and minimizing the fouling resistance using Taguchi method in ultrafiltration (UF) treatment of the real produced water. At first, the optimal operating conditions were found at a temperature of 45°C, TMP = 4 bar, and CFV of 2.25 m/s. To determine the most significant parameters affecting the response parameters, an analysis of variance was employed. In the second stage, performance of applied polymeric membrane in the UF system was studied under...

Generation of various carbon nanostructures in water using IR/UV laser ablation

, Article Journal of Physics D: Applied Physics ; Volume 46, Issue 16 , March , 2013 ; 00223727 (ISSN) Mortazavi, S. Z ; Parvin, P ; Reyhani, A ; Mirershadi, S ; Sadighi Bonabi, R ; Sharif University of Technology

2013

Abstract

A wide variety of carbon nanostructures were generated by a Q-switched Nd : YAG laser (1064 nm) while mostly nanodiamonds were created by an ArF excimer laser (193 nm) in deionized water. They were characterized by transmission electron microscopy, Raman spectroscopy and x-ray photoelectron spectroscopy. It was found that the IR laser affected the morphology and structure of the nanostructures due to the higher inverse bremsstrahlung absorption rate within the plasma plume with respect to the UV laser. Moreover, laser-induced breakdown spectroscopy was carried out so that the plasma created by the IR laser was more energetic than that generated by the UV laser

Optimization of operating conditions in ultrafiltration process for produced water treatment via Taguchi methodology

, Article Desalination and Water Treatment ; Volume 54, Issue 10 , May , 2015 , Pages 2669-2680 ; 19443994 (ISSN) Reyhani, A ; Sepehrinia, K ; Seyed Shahabadi, S. M ; Rekabdar, F ; Gheshlaghi, A ; Sharif University of Technology

Taylor and Francis Inc 2015

Abstract

This paper describes how to find optimal operating conditions of three controlling parameters, i.e. temperature, transmembrane pressure (TMP), and cross-flow velocity (CFV) for maximizing the permeate flux and total organic carbons (TOC) rejection, and minimizing the fouling resistance using Taguchi method in ultrafiltration (UF) treatment of the real produced water. At first, the optimal operating conditions were found at a temperature of 45°C, TMP = 4 bar, and CFV of 2.25 m/s. To determine the most significant parameters affecting the response parameters, an analysis of variance was employed. In the second stage, performance of applied polymeric membrane in the UF system was studied under...

Hydrogen storage in decorated multiwalled carbon nanotubes by Ca, Co, Fe, Ni, and Pd nanoparticles under ambient conditions

, Article Journal of Physical Chemistry C ; Volume 115, Issue 14 , 2011 , Pages 6994-7001 ; 19327447 (ISSN) Reyhani, A ; Mortazavi, S. Z ; Mirershadi, S ; Moshfegh, A. Z ; Parvin, P ; Golikand, A. N ; Sharif University of Technology

2011

Abstract

We report a study on hydrogen storage in Ca, Co, Fe, Ni, and Pd decorated multiwalled carbon nanotubes (MWCNTs) by using two techniques: volumetric and electrochemical. The results showed that hydrogen molecules are adsorbed on the defect sites and transported to the spaces between adjacent carbon via diffusion through both defect sites and opened tips into the layers. Hydrogen storage capacity can be improved in the decorated MWCNT by Co, Fe, Ni, and Ca metals in two approaches: (i) H2 adsorption via Kubas interaction and (ii) dissociation of H2 molecules on the metal particles. The results reveal that Pd are more effective catalyst for hydrogen storage process. It was found that...

Long-term investigation on the phase stability, magnetic behavior, toxicity, and MRI characteristics of superparamagnetic Fe/Fe-oxide core/shell nanoparticles

, Article International Journal of Pharmaceutics ; Volume 439, Issue 1-2 , 2012 , Pages 28-40 ; 03785173 (ISSN) Masoudi, A ; Madaah Hosseini, H. R ; Seyed Reyhani, S. M ; Shokrgozar, M. A ; Oghabian, M. A ; Ahmadi, R ; Sharif University of Technology

2012

Abstract

To efficiently enhance the contrast obtaining from magnetic resonance imaging (MRI), pharmaceutical grade colloidal dispersions of PEG coated iron-based nanoparticles were prepared and compared to conventional pure iron oxide contrast agent. In this study, we synthesized ∼14 nm iron nanoparticles via NaBH4 reduction of iron(III) chloride in an aqueous medium. The resulting nanoparticles were further oxidized by two different methods via (CH3)3NO oxygen transferring agent and exposure to oxygen flow. XRD and electron microscopy analyses confirmed the formation of a second layer on the surface of α-Fe core. As magnetic measurements and Mössbauer spectra of 4-months post prepared nanoparticles...