Sharif Digital Repository / Sharif University of Technology / Search result

Effect of Geometric Distortion on the Flow Field and Performance of an Axisymmetric Supersonic Inlet

, M.Sc. Thesis Sharif University of Technology Akbarzadeh, Hossein (Author) ; Farahani, Mohammad (Supervisor)

Abstract

Inlets must decelerate the air with lowest loss and drag together with a given pressure and Mach number with best quality and uniformity to the engine. This is done based on flight Mach number, by an arrangement of shock waves and surfaces gradient in the inlet. Any distortion in the flow field and the inlet geometry parameters may disrupt such arrangement and influence on the inlet performance, in addition, under critical conditions, it might affect the stability of the intakes. Any distortion in the flow field and the inlet geometry parameters may disrupt such arrangement and influence on the inlet performance, in addition, under critical conditions, it might affect the stability of the...

Numerical Investigation of Dewetting of Evaporating thin Films over Nanometric Topography

, M.Sc. Thesis Sharif University of Technology Akbarzadeh, Amir Mahdi (Author) ; Moosavi, Ali (Supervisor)

Abstract

Evaporation and condensation of thin films can rupture or stabilize thin film .We show that evaporation hastens dewetting of a thin film. Dewetting over nanometric downward step causes pinning of the contact line near the step. This phenomena is not permanent and after certain time that contact angle reaches to its critical value depinnnig happens. We also study the effect of the step size, contact angle, film thickness, slip and evaporation on the depinning time of the contact line. We show that depinnig time has a reverse relation with the rate of evaporation

A molecular-dynamics study of thermal and physical properties of platinum nanoclusters

, Article Fluid Phase Equilibria ; Volume 280, Issue 1-2 , 2009 , Pages 16-21 ; 03783812 (ISSN) Akbarzadeh, H ; Parsafar, G. A ; Sharif University of Technology

2009

Abstract

Metallic nanoclusters are interesting because of their utility in catalysis and sensors. The thermal and physical characteristics of metallic Pt nanoclusters with different sizes were investigated via molecular-dynamics simulations using Quantum Sutton-Chen (QSC) potential. This force field accurately predicts solid and liquid states properties as well as melting of the bulk platinum. Molecular dynamic simulations of Pt nanoclusters with 256, 456, 500, 864, 1372, 2048, 2916, 4000, 5324, 6912, 8788 atoms have been carried out at various temperatures. The Pt-Pt radial distribution function, internal energy, heat capacity, enthalpy, entropy of the nanoclusters were calculated at some...

Pt–NiO–Al2O3/G derived from graphene-supported layered double hydroxide as efficient catalyst for p-nitrophenol reduction

, Article Research on Chemical Intermediates ; Volume 43, Issue 10 , 2017 , Pages 5829-5839 ; 09226168 (ISSN) Akbarzadeh, E ; Gholami, M. R ; Sharif University of Technology

2017

Abstract

The present work reports the synthesis of a Pt-modified NiO–Al2O3 nanocomposite derived from graphene-supported layered double hydroxide (Pt–NiO/G) and demonstrates its catalytic activity. The resulting Pt–NiO/G nanocomposite was characterized by FT-IR, XRD, FE-SEM, TEM and XPS techniques and used for catalytic reduction of p-nitrophenol (P-NP) to p-aminophenol (P-AP). The influence of graphene on catalytic activity was comparatively considered by preparation of Pt–NiO nanoparticles derived from layered double hydroxide. The superior catalytic performance of Pt–NiO/G was ascribed to the synergistic effect between Pt and NiO. Furthermore, reduction of P-NP was considered to follow a...

Experimental investigation and crystal plasticity-based prediction of AA1050 sheet formability

, Article Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture ; Volume 231, Issue 8 , 2017 , Pages 1341-1349 ; 09544054 (ISSN) Hajian, M ; Assempour, A ; Akbarzadeh, A ; Sharif University of Technology

SAGE Publications Ltd 2017

Abstract

This article presents a crystal plasticity methodology to evaluate the AA1050 sheet formability. In order to determine the orientation distribution of the crystals, initial texture of the material is measured through X-ray diffraction technique. Also, the stress-strain behavior of the material is determined by performing tensile test. In order to simulate the path-dependent crystal plasticity behavior of body-centered cubic crystal structures, a UMAT subroutine that employs the rate-dependent crystal plasticity model along with the power law hardening was developed previously by the authors and linked to the finite element software ABAQUS. This subroutine was further developed to simulate...

Synthesis and Characterization of Multinuclear Platinum Complexes Containing Copper Group Metals and 2,6-Diphenylphosphinopyridin Bridging Ligand

, M.Sc. Thesis Sharif University of Technology Akbarzadeh Khoei, Mahtab (Author) ; Jamali, Sirous (Supervisor)

Abstract

In this project, we prepared two new tetranuclear clusters with linear Pt2Ag2 and Pt2Au2 metal cores. First, The tetranuclear cluster [Ag2Pt2(Cl2)(bhq2)(μ-(PPh2)2py)2](OTf)2, 1, from the reaction of 1 equivalent of Pt(bhq)Cl(SMe2), with 1 equivalent of AgOTf and μ-(PPh2)2py ligand has been prepared. Secondly, the tetranuclear cluster [Au2Pt2 (μ-(PPh2)2py)2(Cl2)(bhq2)]( PF6 )2, 3, by the reaction of 1 equivalent of the mononuclear complex [Au(μ-(PPh2)2py)2]PF6 with 1 equivalent of PtbhqClSMe2 and μ-(PPh2)2py ligand has been prepared. Structure of complexes has been fully characterized in solution, solid and gas states using multinuclear NMR spectroscopy, X-ray crystallography and ESI-MS...

Surface free energy of platinum nanoparticles at zero pressure: A molecular dynamic study

, Article Solid State Communications ; Volume 150, Issue 5-6 , February , 2010 , Pages 254-257 ; 00381098 (ISSN) Akbarzadeh, H ; Abroshan, H ; Parsafar, G. A ; Sharif University of Technology

2010

Abstract

Metallic nanoparticles are interesting because of their use in catalysis and sensors. The surface energy of the FCC platinum nanoparticles are investigated via molecular dynamics simulation using Quantum Sutton-Chen (QSC) potential. We have calculated the Gibbs free energy for the FCC platinum bulk and also for its nanoparticle. All calculations have been carried out at zero pressure. We have used the thermodynamic integration method to obtain the Gibbs free energy. The total Gibbs free energy is taken as the sum of its central bulk and its surface free energy. We have calculated the free energy of a platinum nanoparticle as a function of temperature

Experimental and analytical studies on the prediction of forming limit diagrams

, Article Computational Materials Science ; Volume 44, Issue 4 , 2009 , Pages 1252-1257 ; 09270256 (ISSN) Ahmadi, S ; Eivani, A. R ; Akbarzadeh, A ; Sharif University of Technology

2009

Abstract

Metal forming processes are widely used in industrial productions, automobile bodies, food industries, oil refineries, and liquid and gas transmission systems. Analyzing these processes is very important to reduce wastes and optimize the processes. Study of some main factors such as physical and mechanical properties of material and its formability, die geometry, die material, lubrication and pressing speed has been the topic of many research projects. In this paper, forming limit diagrams (FLDs) for LC and ULC steels and the effect of different parameters like the work-hardening exponent, n, and the plastic strain ratio, r, on these diagrams have been evaluated and simulated using...

An experimental and theoretical study on the prediction of forming limit diagrams using new BBC yield criteria and M-K analysis

, Article Computational Materials Science ; Volume 44, Issue 4 , 2009 , Pages 1272-1280 ; 09270256 (ISSN) Ahmadi, S ; Eivani, A. R ; Akbarzadeh, A ; Sharif University of Technology

2009

Abstract

In the present paper, a comprehensive study on the prediction of forming limit diagrams (FLDs) for an AA3003-O aluminium alloy is developed theoretically and experimentally. For obtaining the experimental FLDs, an out-of-plane formability test was performed based on the technique proposed by Ozturk and Lee [F. Ozturk, D. Lee, J. Mater. Process. Technol. 170 (2005) 247-253]. The classical Marciniak-Kuczynski (M-K) model and some new yield criteria are utilized to simulate the necking phenomenon and calculate the limit strains theoretically. The employed yield functions are: the BBC2000, BBC2002, and BBC2003 yield criteria proposed by Banabic et al. [D. Banabic, S.D. Comsa, T. Balan, in:...

γ' Precipitate dissolution during heat treatment of nimonic 115 superalloy

, Article Materials and Manufacturing Processes ; Volume 24, Issue 5 , 2009 , Pages 559-563 ; 10426914 (ISSN) Shahriari, D ; Sadeghi, M. H ; Akbarzadeh, A ; Sharif University of Technology

2009

Abstract

In precipitation hardenable materials, it is desirable to determine the precipitate dissolution temperature for homogenizing the microstructure by controlling the size and distribution of the precipitates. In this research, differential thermal analysis, dilatometry technique, heat treatments followed by microstructure evaluation were used to determine the -γ' dissolution temperature of Nimonic 115. It is assumed that the variation of enthalpy is governed by the changes in y volume fraction and γ concentration with time and temperature, and any contribution of the coarsening of γ' is neglected. The values obtained for the solvus temperature of γ precipitates by the three methods are all in...

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...

Modeling of high temperature rheological behavior of AZ61 Mg-alloy using inverse method and ANN

, Article Materials and Design ; Volume 29, Issue 9 , 2008 , Pages 1701-1706 ; 02641275 (ISSN) Talebi Anaraki, M ; Sanjari, M ; Akbarzadeh, A ; Sharif University of Technology

2008

Abstract

Inverse method and artificial neural network were employed in modeling the rheological behavior of the AZ61 Mg alloy. The hot deformation behavior of these alloys was investigated by compression tests in the temperature range 250-350 °C and strain rate range 0.0005-0.1 s-1. Investigation of stress-strain curves and microstructure of the compression specimen illustrate occurrence of dynamic recrystallization. To determining parameters of two suggested constitutive equations global optimization technique, genetic algorithm, was used. The predicted results by inverse method and ANN depicted a good agreement with the experimental data even if the ANN results has shown the best predicted...

Using molecular dynamic simulation data of calcite in a wide pressure range to calculate some of its thermodynamic properties via some universal equations of state

, Article Molecular Physics ; Volume 106, Issue 21-23 , 2008 , Pages 2545-2556 ; 00268976 (ISSN) Akbarzadeh, H ; Shokouhi, M ; Parsafar, G. A ; Sharif University of Technology

2008

Abstract

Molecular dynamics, MD, simulation of calcite (CaCO3) is selected to compare the p-v-T behaviour of some universal equations of state, UEOS, for the temperature range 100 K ≤ T 800 ≤ K, and pressures up to 3000 kbar. The isothermal sets of p-v-T data generated by simulation were each fitted onto some three- and two-parameter EOSs including Parsafar and Mason (PM), Linear Isotherm Regularity (LIR), Birch-Murnaghan (BM), Shanker, Vinet, Baonza and Modified generalized Lennard-Jones (MGLJ) EOSs. It is found that the MD data satisfactorily fit these UEOS with reasonable precision. Some features for a good UEOS criteria such as temperature dependencies of coefficients, pressure deviation,...

Make Policy for Optimizing Iran Gas Export

, M.Sc. Thesis Sharif University of Technology Alvandi, Mehdi (Author) ; Maleki, Abbas (Supervisor)

Abstract

This project examines four alternatives such as pipelines, oil injection wells, LNG & GTL in the purpose of Iran gas utilization. In this Project four strategies using cost/benefit analysis are examined. For this purpose, at first the cost of inlet feed gas per Mmbtu are calculated. Then regarding various scenarios of average world gas prices for the following thirty years, the cost & benefit of any way will be counted. Then with the use of energy security, the project will make energy policy. For this purpose, Shannon indicator will be used as one of the most reliable indicators. Due to the of use this indicator, the popular project will be chosen accordingly as a certain amount of gas the...

Development of an Analytical Framework for Evaluation of Climate Change Mitigation Policies on Iran’s Energy Security

, M.Sc. Thesis Sharif University of Technology Eshraghi, Hadi (Author) ; Maleki, Abbas (Supervisor)

Abstract

Climate change and energy security are key drivers for future energy policy. While energy security has been a pillar of energy policy for about a century, concern about climate change is more recent and is bound to radically change the landscape of energy policy. Policy makers are now under increasing pressure to address these twin challenges: to develop cost-effective policies that will both ensure the security of our energy system and reduce greenhouse gas emissions.
Main Effort in this Project is to construct an integrated model of Iran’s energy system to serve as a policy analysis tool, by which policymakers are able to identify the future effects of a wide range of policies in...

(Assessing the Role of Carbon Capture and Storage Technology on Iran’s Oncoming Energy System(Technology Deployment Policy Making

, M.Sc. Thesis Sharif University of Technology Banan, Zoya (Author) ; Maleki, Abbas (Supervisor)

Abstract

Based on International Energy Agency studies, achievement of 450 ppm CO2-equivalent emission target in global emission means that the CO2 emissions in 2050 must be reduced to %50 of 2005 level, and this implies that a portfolio of emission reduction policies and strategies need to be exploited through current century.
At the present time, Carbon Capture and Storage (CCS) Technology is a dominant strategy among all the long-term carbon abatement strategies in many countries. Nevertheless, its potential as a climate mitigating option will be proved, only if it is implemented in the countries which are developing at a great pace and taking advantage of fossil fuels in order to afford their...

Diffusion of Lipid and Protein Molecules in Cell Membranes

, Ph.D. Dissertation Sharif University of Technology Khoshnood, Atefeh (Author) ; Jalali, Abbas (Supervisor)

Abstract

Lipid membranes are fundamental constituents of cell membranes and are now used in lap-on-a-chip technology. Membranes in living cells contain a significant fraction of proteins, which undergo lateral random movements due to thermal fluctuations and shear forces imposed by the solvent fluid. Prominent natural and biotechnological systems where membranes are highly sheared include the plasma membrane of endothelial cells, and membranes used in biosensors for high throughput screening of drug candidates, and in water purification devices. In these systems membrane is in direct contact with the mainstream suspension flow, which is driven by pressure gradients. The efficiency and function of...

Assessment of Caspian Gas Transit and its Effects on the Interests of the Iranian Desired

, M.Sc. Thesis Sharif University of Technology Khakpour, Hossein (Author) ; Maleki, Abbas (Supervisor)

Abstract

In this project a model for the analysis and assessment of gas transit in the Caspian Sea and its effects on the desired benefits of the approach of decision-making, has been developed.
The first comprehensive review of the supply and demand of gas in the world and the countries of the Caspian region and the cast has been affecting world energy developments.After a comprehensive analysis of the status of the gas transit routes from the Caspian region and provided. Then, using the Delphi method and elite views the main criteria related to gas transit and affecting the interests of the countries of the Caspian region to determine the detailed criteria for each main criterion was determined...