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    Process optimization and modeling of heavy metals extraction from a molybdenum rich spent catalyst by aspergillus niger using response surface methodology

    , Article Journal of Industrial and Engineering Chemistry ; Volume 18, Issue 1 , January , 2012 , Pages 218-224 ; 1226086X (ISSN) Mafi Gholami, R ; Mousavi, S. M ; Borghei, S. M ; Sharif University of Technology
    2012
    Abstract
    The present study examines the biorecovery of heavy metals from a spent refinery catalyst obtained from one of the oil refineries in Iran using Aspergillus niger. Bioleaching experiments were carried out in batch cultures using A. niger in the one-step process to mobilize Co, Mo and Ni from hazardous spent catalysts. Response surface methodology (RSM) was applied for the design and analysis of experiments with the optimization of pH, temperature, inoculum percentage, pulp density and rotation speed during the bioleaching of the metals. Experiments were designed as per the central composite design (CCD) technique. Three cubic mathematical models were derived for prediction of the responses.... 

    Heavy metals recovery from spent catalyst using acidithiobacillus ferrooxidans and acidithiobacillus thiooxidans

    , Article ICCCE 2010 - 2010 International Conference on Chemistry and Chemical Engineering, Proceedings, 1 August 2010 through 3 August 2010, Kyoto ; 2010 , Pages 331-335 ; 9781424477647 (ISBN) Mafi Gholami, R ; Borghei, S. M ; Mousavi, S. M ; Sharif University of Technology
    2010
    Abstract
    In this investigation, a spent processing catalyst from one of the oil refineries in Iran was initially characterized physically and chemically. Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans were used to mobilize aluminum, cobalt, molybdenum and nickel from hazardous spent catalysts. Bioleaching experiments were performed in batch cultures. The growth characteristics of the bacteria (pH, Eh, cell concentration and ferrous and ferric iron concentration) were determined during bioleaching along with the concentration of metal values extracted from the catalyst. The results obtained from Inductive coupled plasma-optical emission spectrometry (ICP-OES) showed that after the... 

    Determine oil content in petroleum waxes

    , Article Hydrocarbon Processing ; Volume 85, Issue 6 , 2006 , Pages 95-97 ; 00188190 (ISSN) Mafi, M ; Yazdani, F ; Farhadi, F ; Sharif University of Technology
    2006

    STATCOM System Cooling Optimization

    , M.Sc. Thesis Sharif University of Technology Mafi, Behrang (Author) ; Rajabi Qahnuyeh, Abbas (Supervisor)
    Abstract
    Today's electric power industry is unthinkable without high-power electronic converters. Statcom is one of the critical equipment; which is known for its quick response in reactive power compensation/supply. Losses in a high-power system are considerable. Most of these losses are caused by switching. In a conventional system, the cooling system is used only to control the temperature and stable operation of the switches. In this project, an attempt is made to evaluate the temperature of the outlet fluid for use in the Rankine cycle with organic materials by modeling the heat-generating parts in the Statcom equipment. Also, the unification of the Stacom cooling system with the Rankine cycle... 

    Strategies for improving MDA-based development processes

    , Article SMS 2010 - UKSim/AMSS 1st International Conference on Intelligent Systems, Modelling and Simulation, 27 January 2010 through 29 January 2010, Liverpool ; 2010 , Pages 152-157 ; 9780769539737 (ISBN) Fahmideh Gholami, M ; Ramsin, R ; Sharif University of Technology
    2010
    Abstract
    The Model Driven Architecture (MDA) is meant to facilitate system development by using models for representing both the "problem" and its "solution". In its ideal form, software development based on MDA would follow a development process that begins by producing models of the problem domain at a high level of abstraction, and then proceeds by gradually and automatically transforming them into executable code with the help of tools. However, MDA-based development has encountered several setbacks, the mitigation of which requires detailed scrutiny and analysis. In this research, MDA-based development is analyzed through applying SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis... 

    Test Case Selection in Test-Driven Development

    , Ph.D. Dissertation Sharif University of Technology Mafi, Zohreh (Author) ; Mirian Hosseinabadi, Hassan (Supervisor)
    Abstract
    The large number of unit tests produced in the test-driven development (TDD) method and the iterative execution of these tests extend the regression test execution time in TDD. This study aims to reduce test execution time in TDD. We propose a TDD-based approach that creates traceable code elements and connects them to relevant test cases to support regression test selection during the TDD process. Our proposed hybrid technique combines text and syntax program differences to select related test cases using the nature of TDD. We use a change detection algorithm to detect program changes. Our experience is reported with a tool called RichTest, which implements this technique. To evaluate our... 

    Physical and hydraulic properties of a new spring packing

    , Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) Mafi, M ; Yazdani, F ; Farhadi, F ; Deldari, H ; Sharif University of Technology
    2006
    Abstract
    Physical and hydraulic properties of new stainless steel spring packing are introduced. The measured hydraulic properties are: dry and wetted packed bed pressure drop, loading and flooding points and the liquid holdups. The appropriate coefficients for predicting the mentioned hydraulic properties from different correlations are also reported. Hydraulic properties for this packing are compared with available packings. In spite of small size, the dry and wetted packed bed pressure drops of spring packing are less than similar Raschig and Protruded rings. The total liquid holdup of this packing is greater than other commercial packings. The big total liquid holdup and physical surface area are... 

    Solvatochromic probes absorbance behavior in mixtures of 2-hydroxy ethylammonium formate with methanol, ethylene glycol and glycerol

    , Article Journal of Solution Chemistry ; Volume 39, Issue 10 , 2010 , Pages 1509-1519 ; 00959782 (ISSN) Salari, H ; Harifi Mood, A. R ; Elahifard, M. R ; Gholami, M. R ; Sharif University of Technology
    2010
    Abstract
    Solute-solvent and solvent-solvent interactions were investigated for binary mixtures of an ionic liquid (IL) 2-hydroxy ethylammonium formate as with methanol, ethylene glycol and glycerol. The physicochemical properties of the solvent mixtures at 25 °C, over the whole range of mole fractions, were determined using solvatochromic probes. High normal polarity (ETN) in the alcohol-rich region confirms solute-solvent interactions in this medium. Dipolarity/polarizability (π *) show a different trend to ETN with a positive deviation from ideal behavior in IL-glycerol mixtures. However, these deviations for other solvent mixtures are insignificant. Contrary to what is observed for E TN and π*,... 

    Reaction kinetics investigation of 1-fluoro-2,4-dinitrobenzene with substituted anilines in ethyl acetate-methanol mixtures using linear and nonlinear free energy relationships

    , Article Journal of Physical Organic Chemistry ; Volume 24, Issue 11 , 2011 , Pages 1095-1100 ; 08943230 (ISSN) Jamali Paghaleh, J ; Harifi Mood, A. R ; Gholami, M. R ; Sharif University of Technology
    2011
    Abstract
    Aromatic nucleophilic substitution reaction of 1-fluoro-2,4-dinitrobenzene with para-substituted and meta-substituted anilines was kinetically investigated in the mixtures of ethyl acetate and methanol at room temperature. The correlation of second-order rate coefficients with Hammett's substituent constants yields a fairly linear straight line with negative slope in different mole fractions of ethyl acetate-methanol mixtures. The measured rate coefficients of the reaction demonstrated a dramatic variation in ethyl acetate-methanol mixtures with the increasing mole fraction of ethyl acetate. Linear free energy relationship (LFER) investigations confirm that polarity has a major effect on the... 

    The effect of multiwalled carbon nanotubes and activated carbon on the morphology and photocatalytic activity of TiO2/C hybrid materials

    , Article Catalysis Science and Technology ; Volume 1, Issue 2 , 2011 , Pages 279-284 ; 20444753 (ISSN) Zarezade, M ; Ghasemi, S ; Gholami, M. R ; Sharif University of Technology
    2011
    Abstract
    TiO2 nanoparticles supported on activated carbon (AC) and multiwalled carbon nanotubes (MWCNTs) were prepared by the sol-gel method using ultrasonic irradiation. All the prepared samples were calcined at different temperatures and characterized by X-ray diffraction, nitrogen adsorption/desorption isotherms, scanning electron microscopy, transmission electron microscopy and diffuse reflectance spectroscopy. The effects of size and type of carbon on the morphology and photocatalytic activity of the resulting hybrid materials were investigated. The results showed that a decrease in the size of the carbon led to a decrease in size of TiO2 nanoparticles. Both AC and MWCNTs retarded the... 

    Ag3PO4/BiPO4 p-n heterojunction nanocomposite prepared in room-temperature ionic liquid medium with improved photocatalytic activity

    , Article Materials Science in Semiconductor Processing ; Volume 39 , 2015 , Pages 506-514 ; 13698001 (ISSN) Mohaghegh, N ; Rahimi, E ; Gholami, M. R ; Sharif University of Technology
    Elsevier Ltd  2015
    Abstract
    Abstract A visible-light-active Ag3PO4/BiPO4 nanocomposite with a p-n heterojunction structure was fabricated via a co-precipitation hydrothermal process using 2-hydroxylethylammonium formate (RTIL) as a room-temperature ionic liquid. The resulting catalysts were characterized by various techniques. The photocatalytic activity of the photocatalysts was evaluated by the photodegradation of phthalocyanine Reactive Blue 21 (RB21) under both visible and UV light irradiations. The results reveal that the heterojunction composite prepared in RTIL noticeably exhibited an improvement in both efficiency and rate of RB21 photodegradation in comparison with pure Ag3PO4 and BiPO4. The enhanced... 

    Theoretical study of protic solvents hydrogen bonding effect, on the reaction of cyclopentadiene and vinyl acetate; apart from the bulk properties

    , Article Journal of Molecular Structure: THEOCHEM ; Volume 909, Issue 1-3 , 2009 , Pages 86-90 ; 01661280 (ISSN) Irani, M ; Haqgu, M ; Gholami, M. R ; Sharif University of Technology
    2009
    Abstract
    Ab initio, DFT, Monte Carlo statistical mechanics and atom in molecule methods have been applied to investigate the hydrogen bonding effect of protic solvents, apart from the bulk properties, on the reaction of cyclopentadiene and vinyl acetate. The results show that methanol accelerates the rate of the reaction more than water. DFT calculations demonstrate that the interaction of the carbonyl group oxygen atom with solvent molecules in transition state is stronger and more effective than the ether-type oxygen atom. Also, when the solvent molecule is near the oxygen of the carbonyl group the rate of reaction is larger than when it is near the ether-type oxygen. In addition, methanol... 

    Supported PtxPd1-x bimetallic nanoparticles on ionic liquid-functionalized SiO2@graphene oxide nanocomposite and its application as an effective multiphasic catalyst

    , Article Applied Catalysis A: General ; Volume 579 , 2019 , Pages 30-43 ; 0926860X (ISSN) Kohantorabi, M ; Giannakis, S ; Gholami, M. R ; Sharif University of Technology
    Elsevier B.V  2019
    Abstract
    In this work, PtxPd1-x (x = 0, 0.5, and 1)nanoparticles (NPs)were synthesized on the surface of SiO2@graphene oxide which covered by 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF6)ionic liquid (IL)layer. FT-IR spectroscopy, zeta potential, CHN elemental analysis, XRD, XPS, SEM, EDX, TEM, TGA, BET, and ICP-AES techniques were applied for the characterization of the multiphasic catalyst. The as-prepared nanocomposite was used as an effective heterogeneous catalyst for the oxidation of cyclohexene by molecular oxygen, as a green oxidant. Different experimental conditions such as oxygen pressure, reaction time, reaction temperature and amount of catalyst were investigated in this... 

    Zeolitic imidazolate framework-derived Ag/C/ZnO for rapid reduction of organic pollutant

    , Article Journal of the Iranian Chemical Society ; Volume 16, Issue 5 , 2019 , Pages 1105-1111 ; 1735207X (ISSN) Falamarzi, M ; Akbarzadeh, E ; Gholami, M. R ; Sharif University of Technology
    Springer Verlag  2019
    Abstract
    One of the appealing usages of metal–organic frameworks is their application in manufacturing of metal oxide and metal oxide nanocomposites. In the present study, we used zeolitic imidazolate framework (ZIF-8) as precursor to prepare a new Ag/C/ZnO catalyst. The as-prepared samples were characterized using X-ray diffraction, Fourier-transform infrared, scanning electron microscopy and transmission electron microscopy analysis. Improved catalytic performance of as-prepared Ag/C/ZnO was confirmed by reduction of organic pollutants including p-nitrophenol, methylene blue and rhodamine-B in the presence of NaBH 4 in aqueous media. The synergistic effect between Ag and ZnO was proposed as the... 

    Visible light photocatalytic performance of Ag2O/ZnCr-LDH nanocomposite

    , Article Chemical Physics Letters ; Volume 751 , 2020 Akbarzadeh, E ; Rasteh, M ; Gholami, M. R ; Sharif University of Technology
    Elsevier B.V  2020
    Abstract
    Ag2O particles were loaded on the surface of ZnCr-LDH via an anion-exchange precipitation approach by using privilege of the memory trace feature of the LDH-type materials. The structural properties of the resulted photocatalyst were explored by different spectroscopic and microscopic methods. The photocatalytic studies on acid black degradation ascertained that the prepared Ag2O/ZnCr-LDH nanocomposite represented an observably increased degradation performance of organic pollutants compared with pure Ag2O and ZnCr-LDH. This improved photocatalytic performance can be ascribed to the enhanced surface area, good order distributing of particles and effective charge carrier transfer and... 

    Au and Pt nanoparticles supported on Ni promoted MoS2 as efficient catalysts for p-nitrophenol reduction

    , Article Journal of Water Process Engineering ; Volume 34 , 2020 Akbarzadeh, E ; Bahrami, F ; Gholami, M. R ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    In present study, an efficient method was used to synthesis Au and Pt nanoparticles on Ni modified MoS2 (MNi/MoS2 (M = Au and Pt). The morphology and structure of the prepared products were characterized using different microscopic and spectroscopic methods. The as-synthesized MNi/MoS2 nanocomposites were applied for catalytic reduction of p-nitrophenol (P-NP) in the presence of NaBH4. P-NP is one of the prevalent contaminants in wastewaters, while its corresponding aromatic amine (4-aminophenol) is a precious intermediate for manufacturing of important materials such as pharmaceuticals. The obtained catalytic results indicated that noble metal nanoparticles significantly affect catalytic... 

    Synthesis of M/CuO (M = Ag, Au) from Cu based metal organic frameworks for efficient catalytic reduction of p-nitrophenol

    , Article Materials Chemistry and Physics ; Volume 198 , 2017 , Pages 374-379 ; 02540584 (ISSN) Akbarzadeh, E ; Falamarzi, M ; Gholami, M. R ; Sharif University of Technology
    2017
    Abstract
    Metal Organic Frameworks (MOFs) have received enormous attention in catalysis field due to their special structures and various promising applications. One of the intriguing applications of MOFs is utilization of them as precursors for synthesis of metal oxide nanomaterials. Base on this strategy, in this work, we have applied Cu-MOF to prepare a series of noble metal nanoparticles (Ag and Au) decorated CuO (M/CuO) as efficient catalyst. As-prepared nanocomposites were characterized by various analytical techniques and their catalytic performances appraised by using of the catalytic reduction of p-nitrophenol to p-aminophenol as a reliable model reaction. Experimental results suggest that... 

    Theoretical study of solvent and substituent effects on the reactions of 1,4-benzoquinone with cyclopentadiene and cyclohexadiene

    , Article Progress in Reaction Kinetics and Mechanism ; Volume 33, Issue 2 , 2008 , Pages 191-206 ; 14686783 (ISSN) Haqghu, M ; Irani, M ; Gholami, M. R ; Sharif University of Technology
    2008
    Abstract
    Ab initio quantum mechanics and ONIOM calculations were used to study solvent and substituent effects on the reactions of 1,4-benzoquinone with cyclopentadiene and cyclohexadiene derivatives in tetrahydrofuran and greater water solvents. These calculations revealed (i) that increasing the number of electron donating methyl group substituents and (ii) the proximity of substituents to the reacting carbons (carbon atoms which contribute to the forming C-C bonds) on the diene, promote charge transfer from the diene to the dienophile in the transition state. © 2008 Science Reviews 2000 Ltd. These effects increase the negative charge on the oxygen atoms, destabilize the transition state in the... 

    Theoretical study of kinetics and mechanism of reactions of hydroxylamine and amineoxide anion with methyl iodide in gas and aqueous phases

    , Article Progress in Reaction Kinetics and Mechanism ; Volume 32, Issue 1 , 2007 , Pages 29-50 ; 14686783 (ISSN) Haqghu, M ; Irani, M ; Gholami, M. R ; Sharif University of Technology
    Science Reviews Ltd  2007
    Abstract
    The kinetics and mechanism of the reactions of hydroxylamine and aminoxide anion with methyl iodide were studied with ab initio calculations, Monte-Carlo and QM/MM simulations in gas and aqueous phases. Geometrical parameters and charge calculations show that these reactions proceed through the SN2 (bimolecular nucleophilic displacement) mechanism only. The solvent effects on these reactions were studied by inserting water molecules in reaction media, Onsager model, Monte-Carlo and QM/MM simulations. Activation parameters indicate the expected variation in activation energy and rate coefficient in aqueous phase in comparison to the gas phase. The shift of potential energy barrier through the... 

    Kinetics and mechanism of 2-pyridylacetic acid pyrolysis in the gas phase: A joint experimental and theoretical study

    , Article Chemical Physics ; Volume 330, Issue 3 , 2006 , Pages 394-400 ; 03010104 (ISSN) Izadyar, M ; Zamani, N ; Gholami, M. R ; Sharif University of Technology
    2006
    Abstract
    A combination of the experimental and theoretical study was carried out on the reaction mechanism associated with the pyrolysis of 2-pyridylacetic acid in the gas phase. Methylpyridine and carbon dioxide were analyzed as the products, using a static system over the pressure range of 18-55 torr and the temperature of 541.2-583.4 K. The experimental kinetic data show that the pyrolysis process is homogeneous, unimolecular and proceeds through a concerted mechanism. Theoretical studies at the B3LYP level using the 6-31G* basis set confirmed an asynchronous concerted mechanism for the reaction. Computed kinetic and activation parameters are in good agreement with the experimental one. © 2006...