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irani--mohammad
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Theoretical Study of Solvent and Substituent Effects on Kinetic and Mechanism of Organic Reactions and Theoretical Study of Enzyme Reactions
, Ph.D. Dissertation Sharif University of Technology ; Gholami, Mohammad Reza (Supervisor)
Abstract
Computational chemistry is used to study solvent and substituent effects on kinetics and mechanism of some organic reactions. It also is used to study enzyme reactions and enzyme structures. Organic reactions were studied by ab initio quantum mechanics and Monte Carlo simulations. The enzyme studies were done by QM/MM and MD methods in Lund University. The studied organic reactions are 1) Reactions of hydroxylamine and aminoxide anion with methyl iodide. 2) Rearrangement of allyl p-tolyl ether. 3) Reactions of 1,4-Benzoquinone with Cyclopentadiene and Cyclohexadiene derivatives and reaction of cyclopentadiene and vinyl acetate. In the enzyme studies the catalytic reaction of Glyoxalase...
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, Issues 1–3 , September , 2009 , Pages 86–90 ; Haqgu, M ; Gholami, M. R. (Mohammad Reza) ; 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...
A joint experimental and theoretical study of kinetic and mechanism of rearrangement of allyl p-tolyl ether
, Article Journal of Molecular Structure: THEOCHEM ; Volume 893, Issues 1–3 , January , 2009 , Pages 73–76 ; Haqgu, M. (Mohammad) ; Talebi, A ; Gholami, M. R. (Mohammad Reza) ; Sharif University of Technology
2009
Abstract
A joint theoretical and experimental study of the kinetic and mechanism of the rearrangement of allyl p-tolyl ether was performed in order to study the kinetic and mechanism of the reaction. Experimental studies were performed in gas phase over a temperature range of 493.15–533.15 K. The experimental Arrhenius parameters of this reaction were measured to be Ea = 36.08 kcal mol−1, ΔS# = −7.88 cal mol−1 K−1, and Log A = 11.74, experimentally. Using GC for the mixture of the reaction with and without cyclohexene demonstrated that the reaction is clean without any radical intermediates. The experimental results show that the studied reaction is unimolecular and proceeds through a concerted...
One Dimensional and Two Dimensional Numerical Investigation of Micro Scale Combustion
, M.Sc. Thesis Sharif University of Technology ; Saidi, Mohammad Said (Supervisor) ; Saidi, Mohammad Hasan (Supervisor) ; Shafii, Mohammad Behshad (Supervisor)
Abstract
In this paper, a one-dimensional and two-dimensional numerical approach is used to study the effect of various parameters such as micro combustor height, mass flow rate and external convection heat transfer coefficient on the temperature and species mass fraction profiles. A premixed mixture of H2-Air with a multi-step chemistry (9 species and 19 reactions) is used. The transient gas phase energy and species conservation equations result in an Advection-Diffusion-Reaction system (A-D-R) that leads to two stiff systems of PDEs, which can not be solved by conventional Computational Fluid Dynamics (CFD) methods. In the present work, Strang splitting method, which is suitable for nonlinear stiff...
A Practical Examination of the Antibacterial and Absorption Effect of Bioceramic Apatite-Coated TiO2 as a Modified Nanophotocatalyst
, M.Sc. Thesis Sharif University of Technology ; Gholami, Mohammad Reza (Supervisor) ; Haghighi, Saeed (Co-Advisor)
Abstract
Ag / AgCl /TiO2 , 2 Ap / Ag / AgCl /TiO , 2 AgI /TiO and 2 Ap / AgI /TiO were prepared by the deposition-precipitation method on 2TiO (P25) nanoparticles and their photocatalyctic activities have been investigated under visible light and dark environments. Cationic surfactant plus 2 PVPI (topical solution and dry powder) as an iodine ion source and nonionic surfactant plus KI as an iodide ion source were used to prepar 2 AgI /TiO . In less than 30 minutes, 2 AgI /TiO which has been resulted from combination of cationic surfactant and 2 PVPI showed high efficiency on Escherichia coli under visible light when small quantities of it is used . However, AgCl sample prepared with cationic...
Elucidating the Roles of Interlukin I Receptor Type II (lL-1Rll) in the Regulation of Human Immune System, Atomistic Molecular Dynamics Simulation
, M.Sc. Thesis Sharif University of Technology ; Ejtehadi, Mohammad Reza (Supervisor) ; Azimzadeh Irani, Maryam (Co-Supervisor)
Abstract
IL-1 family of cytokines plays a critical role in the regulation of immune response.These cytokines transfer the signals to the target cells through binding to the IL-1 receptors.Interleukin 1 Receptor Type II (IL-1RII) is the decoy receptor of the IL-1 cytokines. IL-1RII is homologous to the signaling Interleukin 1 Receptor Type I (IL1RI) in its extracellular region and can bind to the same cytokines with higher affinity and the same accessory protein. It down-regulates the signaling and suppresses the downstream pathways due to the lack of the intracellular Toll-Interleukin Receptor (TIR) domain. IL-1RII is decorated by carbohydrate units in-vivo. Dynamics and ligand binding of receptors...
Efficient high harmonic generation of bromine molecule by controlling the carrier-envelope phase and polarization of driving laser pulse
, Article Chemical Physics Letters ; Volume 719 , 2019 , Pages 27-33 ; 00092614 (ISSN) ; Monfared, M ; Sharif University of Technology
Elsevier B.V
2019
Abstract
The generation of ultrashort attosecond pulse requires both an enhanced high harmonic generation and the spectral-phase control. In the present work, an efficient method is theoretically investigated for extending HHG cutoff energy in Br2 molecule using TDDFT. The effects of molecular orientation and carrier-envelope phase of the laser on the high harmonic spectrum are analyzed. As a result, by the fine modulations of the laser field, the harmonic plateau is enlarged and the position of structure-induced interference minimum shifts. We also provide a physical picture on the intensity dependence of the spectral minima in the harmonic spectra
Numerical Simulation of 2D Compressible Cavitation Flow Using Compact Finite-Difference Method
, M.Sc. Thesis Sharif University of Technology ; Hejranfar, Kazem (Supervisor)
Abstract
In the present study, the numerical simulation of 2D inviscid compressible cavitation flow is performed by using the compact finite-difference method. The problem formulation is based on the multiphase compressible Euler equations with the assumption of the homogeneous equilibrium model and the system of baseline differential equations is comprised of the continuity, momentum and energy equations for the vapor-liquid mixture. To complete the system of governing equations, the ideal gas relation is used for the vapor phase and the Tait relation is applied for the liquid phase, and therefore, the compressibility effects are considered for both the vapor and liquid phases. To analyze the flow...
2D and 3D simulation of bubble columns using CFD methods
, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) ; Bozorgmehri, R ; Sharif University of Technology
2006
Abstract
This article presents the results of 2D and 3D simulations of a bubble column reactor at steady state conditions and low gas flow rates. The simulations have been done based on a two-fluid model with a k - ε model used for turbulence modeling. The experimental data have been obtained by differential pressure transducer. For analyzing of hydrodynamic parameters such as hold up and velocity profiles of phases, a system consists of water tank and air aerated from bottom is set up. The simulations have been done based on two different approaches which are mixture and eulerian approaches. Despite the fact that these approaches lead to similar results, the convergence and stability of eulerian...
An analytical and experimental study of precision forging of aluminum spur gear
, Article Steel Research International, 16 September 2012 through 19 September 2012, Krakow ; Volume SPL. ISSUE , September , 2012 , Pages 163-166 ; 16113683 (ISSN) ; 9783514007970 (ISBN) ; Taheri, A. K ; Sharif University of Technology
Wiley-VCH Verlag
2012
Abstract
An important aspect of production of gears by precision forging process is the prediction of load required to perform the process and to design the forging die. In this research a new kinematically admissible velocity field is presented to predict the forging load by an upper bound analysis. The analysis considers the shape of tooth profile, number of teeth, and frictional conditions between the die/punch and deforming material. To verify the predicted results the 7075 aluminum alloy billets were forged at temperature of 150 to 250 °C in a precision forging die designed to produce a spur gear of 5 teeth. A good agreement was found between the two sets of results at the filling stage of the...
Impact of thermodynamic non-idealities and mass transfer on multi-phase hydrodynamics
, Article Scientia Iranica ; Volume 17, Issue 1 C , JANUARY-JUNE , 2010 , Pages 55-64 ; 10263098 (ISSN) ; Pishvaie, M. R ; Sharif University of Technology
2010
Abstract
Considering the non-ideal behavior of fluids and their effects on hydrodynamic and mass transfer in multiphase. flow is very essential. Simulations were performed that take into account the effects of mass transfer and mixture non-ideality on the hydrodynamics reported by Bozorgmehry et al In this paper, by assuming the density of phases to be. constant and using Raoult's law instead of EOS and the fugacity coefficient definition, respectively, for both liquid and gas phases, the importance of nonideality effects on mass transfer and hydrodynamic behavior was studied. The results for a system of octane/propane (T = 323 K and P = 445 kPa) also indicated that the assumption of constant density...
Hybrid adsorption–photocatalysis properties of quaternary magneto-plasmonic ZnO/MWCNTs nanocomposite for applying synergistic photocatalytic removal and membrane filtration in industrial wastewater treatment
, Article Journal of Photochemistry and Photobiology A: Chemistry ; Volume 391 , 2020 ; Amoli Diva, M ; Sharif University of Technology
Elsevier B.V
2020
Abstract
A new multifunctional filtration membrane was prepared by twofold advantages of conventional polymeric-membrane as the supporting layer and magneto-plasmonic Ag-doped ZnO@Fe3O4/MWCNTs nanocomposite as the functional layer. Poly acrylic acid (PAA)-modified polyamide (PA) discs (PAA-PA) were applied to increase the hydrophilicity of prepared membrane and X-Ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were used for characterization. The grafting yield of PAA in the pores and on the surface of PA was 17 wt.% and weigh difference between PAA-PA membrane before and after modifying with the photocatalyst was 8.7 mg. The amount of photocatalyst loading in the prepared...
Effect of forging temperature on homogeneity of microstructure and hardness of precision forged steel spur gear
, Article Materials Chemistry and Physics ; Volume 112, Issue 3 , 2008 , Pages 1099-1105 ; 02540584 (ISSN) ; Karimi Taheri, A ; Sharif University of Technology
2008
Abstract
Precision forging is a suitable process to produce spur gears due to its advantages such as reduction in machining time and production cost. The homogeneity in microstructure and mechanical properties of precision forging products can highly affect the performance of the gears during their service. In this research the effect of precision forging temperature on homogeneity of microstructure and hardness of forged gears of low carbon steel is studied. The microstructure and hardness map of the gears forged at a temperature range of 750-1150 °C revealed that the forging temperature of 950 °C is an optimum temperature to produce a spur five teeth gear with minimum inhomogeneity in the...
Survying the Process of Photodissociation of Methane with Using the Femto Second Lasers
, M.Sc. Thesis Sharif University of Technology ; Sadighi Bonabi, Rasoul (Supervisor)
Abstract
In this project , the dissociation of methane in the presence of Ti:Sapphire laser with parameters of 1014wcm-2, 800nm wave lengths and 100fs pulse width have been investigated theoretically, by using the Gaussian03 package –computational chemistry program that is capable of predicting many properties of atomic and molecular systems. It is based upon the fundamental laws of quantum mechanism. By considering some limitations in approximate techniques and incapability of advancing them, numerical calculation of solving the time dependent Schrödinger equation in order to improve the results and find more quantum dynamic information is applied. Therefore at first, by Gaussian03 package some of...
Visible light switchable bR/TiO2 nanostructured photoanodes for bio-inspired solar energy conversion
, Article RSC Advances ; Volume 5, Issue 24 , Jan , 2015 , Pages 18642-18646 ; 20462069 (ISSN) ; Janfaza, S ; Irani, R ; Sharif University of Technology
Royal Society of Chemistry
2015
Abstract
Today, regarding the limitation and environmental side effects of fossil fuel resources, solar hydrogen production is one of the main interests in the energy research area. The development of visible light sensitized semiconductors based on non-toxic components, low cost and available bio-species is an ongoing approach for H2 generation based on water splitting reactions. Here, two different morphologies of TiO2 photoanodes, nanoparticulated and nanotubular, have been modified with simply extracted bacteriorhodopsin (bR) without any linker. Achieving a significant enhancement in photoconversion efficiency of TiO2 photoanodes, η% was increased from 2.9 to 16.5 by bR addition to the TiO2...
A review of 2D-based counter electrodes applied in solar-assisted devices
, Article Coordination Chemistry Reviews ; Volume 324 , 2016 , Pages 54-81 ; 00108545 (ISSN) ; Naseri, N ; Beke, S ; Sharif University of Technology
Elsevier
2016
Abstract
The alarming energy and environmental crisis of our modern era necessitates scientists to propose alternatives to replace the scarce and harmful fossil fuels. The Sun, as a free, and abundant clean energy resource, presents a motivation for researchers to convert the sunlight to electrical power and store the H2 as an energy carrier by developing solar cells as well as water splitting devices, respectively. One of the fundamental parts of a solar energy convertor (solar cell/photoelectrochemical device), where the reduction reaction occurs, is the counter electrode (CE); the CE is commonly based on rare Pt. It is critical to substitute costly CEs with efficient, low-cost replacements, which...
GAG positioning on IL-1RI; A mechanism regulated by dual effect of glycosylation
, Article Glycobiology ; Volume 29, Issue 11 , 2019 , Pages 803-812 ; 14602423 (ISSN) ; Ejtehadi, M. R ; Sharif University of Technology
NLM (Medline)
2019
Abstract
IL-1RI is the signaling receptor for the IL-1 family of cytokines that are involved in establishment of the innate and acquired immune systems. Glycosylated extracellular (EC) domain of the IL-1RI binds to agonist such as IL-1β or antagonist ligands and the accessory protein to form the functional signaling complex. Dynamics and ligand binding of the IL-1RI is influenced by presence of the glycosaminoglycans (GAGs) of the EC matrix. Here a combination of molecular dockings and molecular dynamics simulations of the unglycosylated, partially N-glycosylated and fully N-glycosylated IL-1RI EC domain in the apo, GAG-bound and IL-1β-bound states were carried out to explain the co-occurring...
Glycan-mediated functional assembly of IL-1RI: structural insights into completion of the current description for immune response
, Article Journal of Biomolecular Structure and Dynamics ; 2020 ; Ejtehadi, M. R ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
Interleukin 1 Receptor type I (IL-1RI) is a multi-domain transmembrane receptor that triggers the inflammatory response. Understanding its detailed mechanism of action is crucial for treating immune disorders. IL-1RI is activated upon formation of its functional assembly that occurs by binding of the IL-1 cytokine and the accessory protein (Il-1RAcP) to it. X-ray crystallography, small-Angle X-ray Scattering and molecular dynamics simulation studies showed that IL-1RI adopts two types of ‘compact’ and ‘extended’ conformational states in its dynamical pattern. Furthermore, glycosylation has shown to play a critical role in its activation process. Here, classical and accelerated atomistic...
Washcoating and testing of monolithic palladium-only catalytic converters for automobiles
, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) ; Soltanieh, M ; Rashidzadeh, M ; Sharif University of Technology
2006
Abstract
This article presents the research results on production and performance of palladium-only catalytic converters. Monolith is used as catalyst carrier and gamma alumina as substrate. Dipping method is used for monolith washcoating. Palladium as the active metal is impregnated on gamma alumina using wet impregnation to produce catalyst samples. The effects of factors such as percent solid in slurry, milling time, calcination time and temperature, pH and existence of Al(NO3)3 on wash-coat characteristics were studied experimentally. SEM, XRD, and BET tests were carried out on the samples. Catalyst performance was tested in an experimental reactor that was designed for this research. The results...
Glycan-mediated functional assembly of IL-1RI: structural insights into completion of the current description for immune response
, Article Journal of Biomolecular Structure and Dynamics ; Volume 40, Issue 6 , 2022 , Pages 2575-2585 ; 07391102 (ISSN) ; Ejtehadi, M. R ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
Interleukin 1 Receptor type I (IL-1RI) is a multi-domain transmembrane receptor that triggers the inflammatory response. Understanding its detailed mechanism of action is crucial for treating immune disorders. IL-1RI is activated upon formation of its functional assembly that occurs by binding of the IL-1 cytokine and the accessory protein (Il-1RAcP) to it. X-ray crystallography, small-Angle X-ray Scattering and molecular dynamics simulation studies showed that IL-1RI adopts two types of ‘compact’ and ‘extended’ conformational states in its dynamical pattern. Furthermore, glycosylation has shown to play a critical role in its activation process. Here, classical and accelerated atomistic...