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Two-and three-dimensional numerical simulations of supersonic ramped inlet
, Article Scientia Iranica ; Volume 25, Issue 4 , 2018 , Pages 2198-2207 ; 10263098 (ISSN) ; Soltani, M.R ; Sharif University of Technology
Sharif University of Technology
2018
Abstract
Two-dimensional (2D) and three-dimensional (3D) numerical simulations of an external compression supersonic ramped inlet are presented for a free stream Mach number of 2. A comparison made between numerical results and experimental data showed that multi-block structured gird using standard k - " turbulence model gives acceptable results. The shape of present inlet diffuser was transformed gradually into a circular one to encompass the Aerodynamic Interface Plane (AIP). It was observed that the 3D simulation predicted a more accurate static pressure distribution during the length of supersonic inlet and total pressure distribution at the AIP in comparison with the 2D one. Further, a better...
Repeatability of Lithium Adsorption and Desorption on TiO2 Nanotubes from Brines
, M.Sc. Thesis Sharif University of Technology ; Askari, Masoud (Supervisor)
Abstract
Today, recycling lithium as a valuable metal from brine plays an important role in various applications such as battery manufacturing, computers, aerospace and automobiles. Among the aqueous methods available for the extraction of the lithium element in brines, ion exchange by TiO2 nanosorbents is one of the most efficient methods. In this study, first the titanium dioxide nanotubes were well synthesized by anodizing method and the nanograss created after the anodizing process were completely eliminated. Then, the effect of three cathodes of aluminum, graphite and stainless steel in order to select the best cathode and achieve a regular morphology as well as their replacement with platinum...
Assortment Optimization with Demand Learning for Reusable Products
, M.Sc. Thesis Sharif University of Technology ; Modarres, Mohammad (Supervisor)
Abstract
One of the lesser-known issues in the modeling literature of assortment optimization issues is the assortment optimization for reusable products, which is an issue in various areas, including offering parking space, renting cloud computing systems resources, and rental of fashion products, etc.In this issue, we are faced with a high diversity product rental store that has a customer in each period. The seller offers a limited set of products depending on the customer demand and the inventory in hand. He can decide to rent the product or leave the system without renting the product. In case of renting the products by the customer, he may return them until the end of this period or keep them...
Recovery of Vanadium from Leaching Solution of Roasted Isfahan Steelmaking Slag Using Solvent Extraction
, M.Sc. Thesis Sharif University of Technology ; Askari, Masoud (Supervisor)
Abstract
Solvent extraction of vanadium (V) from sulfated leaching solution of the converter slag of the Isfahan steel company followed by stripping of this element from the organic solvent were examined in this study. In the experimental section, 2-ethyl-1-hexanol extractor was utilized for selective separation of V(V) from the acidic medium containing Si, Na, Fe, Al, Ca, and P ions. Ammonium chloride solution was also used for stripping V from the organic phase. Under optimal condition (pH=1.9, T=65℃, extractor concentration of 68% and organic phase volume fraction of 0.66), 91% was extracted in solvent extraction stage. Under optimal stripping conditions (pH=7.5, T=25℃, organic phase volume...
Electrodialysis of Llithium from Spent Lithium-Ion Battries
, M.Sc. Thesis Sharif University of Technology ; Askari, Masoud (Supervisor)
Abstract
In this study, Lithium recovery process from lithium-ion battery was investigated by electrodialysis method. First, the cathode of the battery was leached in NMP to separate cathode from aluminum foil. Then, the cathode was leached in sulfuric acid with concentration 3.25 M and 10 volume percent hydrogen peroxide that pulp density was 55 g/L at 60°C for 100 minutes. in the next step, an electrodialysis cell was designed and created to recover lithium. And the influence of time, voltage, flow rate of feed solution, concentration of electrode solution and concentration of feed solution on process was investigated. Purpose of this project were investigated lithium ion recovery rate, lithium...
Novel proton conducting core-shell PAMPS-PVBS@Fe2TiO5 nanoparticles as a reinforcement for SPEEK based membranes
, Article Scientific reports ; Volume 11, Issue 1 , 2021 , Pages 4926- ; 20452322 (ISSN) ; Javanbakht, M ; Askari, M. B ; Hooshyari, K ; Moradi, M ; Beydaghi, H ; Rastgoo Deylami, M ; Enhessari, M ; Sharif University of Technology
NLM (Medline)
2021
Abstract
In this study, new nanocomposite membranes from sulfonated poly (ether ether ketone) (SPEEK) and proton-conducting Fe2TiO5 nanoparticles are prepared by the solution casting method. Sulfonated core-shell Fe2TiO5 nanoparticles are synthesized by redox polymerization. Therefore, 4-Vinyl benzene sulfonate (VBS) and 2-acrylamide-2-methyl-1-propane sulfonic acid (AMPS) are grafted on the surface of nanoparticles through radical polymerization. The different amounts of hybrid nanoparticles (PAMPS@Fe2TiO5 and PVBS@Fe2TiO5) are incorporated into the SPEEK matrix. The results show higher proton conductivity for all prepared nanocomposites than that of the SPEEK membrane. Embedding the sulfonated...
Effects of wing geometry on wing-body-tail interference in subsonic flow
, Article Scientia Iranica ; Volume 18, Issue 3 B , 2011 , Pages 407-415 ; 10263098 (ISSN) ; Soltani, M. R ; Askari, F ; Pajuhande, H. R ; Sharif University of Technology
2011
Abstract
Extensive wind tunnel tests were performed on several wing- body-tail combinations in subsonic flow to study the effects of wing geometric parameters on the flow field over the tail. For each configuration, tail surface pressure distribution, as well as the velocity contour at a plane perpendicular to the flow direction behind the wing was measured. The results show a strong effect of wing to tail span ratio, as well as wing aspect ratio, on the flowfield downstream of the wing. For low sweep wings, as those considered here, wing and body interference effects on the tail are associated with the wing tip vortex and nose-body vortex
Detection of thermal infrared (TIR) anomalies related to the M s=5.1 earthquake on Oct. 14, 2004 near Ravar (SE Iran)
, Article Journal of the Earth and Space Physics ; Volume 35, Issue 4 , 2010 ; 03781046 (ISSN) ; Hafezi, N ; Rahimi Tabar, M. R ; Ansari, A. R ; Sharif University of Technology
2010
Abstract
Over the last two decades there have been numerous reports from different seismically active regions of the world that thermal infrared (TIR) anomalies can be identified around the epicentral areas before major earthquakes [e.g. (Tronin et al., 2002)]. The TIR anomalies reportedly appear as early as 14 to 7 days before the seismic events and affect areas as large as 1000s to 100,000s km2 in size. Our case study for detection of TIRs using NOAA-AVHRR data(Band 4) is an Ms = 5.1 earthquake that occurred on 14th October 2004 near Ravar in Kerman province located in Loot and Tabas deserts, southeast-central Iran. The area is part of the Golbaf-Sirj seismogenic zone. It includes major faults...
Adjoint-based design optimization of s-shaped intake geometry
, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 3 November 2017 through 9 November 2017 ; Volume 1 , 2017 ; 9780791858349 (ISBN) ; Shoureshi, P ; Soltani, M. R ; Khajeh Fard, A ; ASME ; Sharif University of Technology
2017
Abstract
The S-shaped air intakes are very common shapes due to their ease in the engine-body integration or Radar Cross Section, RCS, specifications especially for fighter aircrafts. The numerical shape optimization of an S-shaped air intake using adjoint method is conducted. The flow of a specified air intake that uses S-duct M2129 is simulated using three dimensional (3D) numerical solution of Reynolds-Averaged Navier-Stokes equation along with k-ω SST turbulence model. The main purpose of this optimization scheme is to maximize the total pressure recovery (TPR). Further, the scheme is developed in such a way that would be applicable in industry thru satisfying specified constraint requirements....
Synergistic effect of MEHPA on co-extraction of zinc and cadmium with DEHPA
, Article Minerals Engineering ; Volume 17, Issue 1 , 2004 , Pages 89-92 ; 08926875 (ISSN) ; Moradkhani, D ; Darvishi, D ; Askari, M ; Behnian, D ; Sharif University of Technology
2004
Abstract
Simultaneous extraction of zinc and cadmium by a mixture of di-2-ethyl hexyl phosphoric acid (DEHPA) and mono-2-ethyl hexyl phosphoric acid (MEHPA), and the synergistic effect of MEHPA on co-extraction of zinc and cadmium with DEHPA have been investigated. It was shown that the extraction of zinc and cadmium by DEHPA and/or MEHPA can be increased by an increase of pH. The results also illustrate that the pH0.5 of zinc, by increase in MEHPA from 0.1 to 8 vol%, did not vary significantly while that of cadmium varies from 0.63 to 2.4. In other words MEHPA prevents selective extraction of zinc from aqueous media containing both zinc and cadmium. Studies on the selective separation parameter...
Investigation of the continuum-rarefied flow and isotope separation using a hybrid CFD-DSMC simulation for UF6 in a gas centrifuge
, Article Annals of Nuclear Energy ; 2020 ; Akbar Salehi, A ; Reza Keshtkar, A ; Mahdi Shadman, M ; Hossein Askari, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
UF6 gas flow in the total regions of a rotor with the radius of 0.1 m and the length of 1 m in axisymmetric and steady states was simulated using a new hybrid CFD-DSMC method in the OpenFOAM framework. Implicit coupled density-based scheme was performed for CFD method, and Variable Hard Sphere (VHS) and diffuse model were employed in DSMC method. Also, as an initial estimation, the local Knudsen number was applied to determine the interface location between the continuum-rarefied regions (r = 0.0855 m). Then it was modified (r = 0.084 m) to reduce the computational cost. The comparison results of pure CFD and CFD-DSMC methods illustrated that there were large differences between the flow...
Investigation of the continuum-rarefied flow and isotope separation using a hybrid CFD-DSMC simulation for UF6 in a gas centrifuge
, Article Annals of Nuclear Energy ; Volume 152 , 2021 ; 03064549 (ISSN) ; Akbar Salehi, A ; Reza Keshtkar, A ; Mahdi Shadman, M ; Hossein Askari, M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
UF6 gas flow in the total regions of a rotor with the radius of 0.1 m and the length of 1 m in axisymmetric and steady states was simulated using a new hybrid CFD-DSMC method in the OpenFOAM framework. Implicit coupled density-based scheme was performed for CFD method, and Variable Hard Sphere (VHS) and diffuse model were employed in DSMC method. Also, as an initial estimation, the local Knudsen number was applied to determine the interface location between the continuum-rarefied regions (r = 0.0855 m). Then it was modified (r = 0.084 m) to reduce the computational cost. The comparison results of pure CFD and CFD-DSMC methods illustrated that there were large differences between the flow...
Nickel-doped monoclinic WO3 as high performance anode material for rechargeable lithium ion battery
, Article Journal of Electroanalytical Chemistry ; Volume 894 , 2021 ; 15726657 (ISSN) ; Javanbakht, M ; Omidvar, H ; Hooshyari, K ; Salarizadeh, P ; Askari, M. B ; Sharif University of Technology
Elsevier B.V
2021
Abstract
The anode materials are one of the critical components in rechargeable lithium ion batteries (LIBs). The monoclinic tungsten trioxide (mWO3) is introduced as interesting anode electrode for LIBs due to its good structure for intercalation and de-intercalation of lithium ions, high abundance and various oxidation state of tungsten and etc. In this study, we prepare and investigate the effect of various amounts of nickel dopant on characteristics and electrochemical properties of the mWO3 as the anode electrode in a rechargeable LIB. The experimental investigations confirm that the number of nickel atoms has a remarkable effect on controlling spherical particle diameter, crystallite size, and...
Application of Sol-Gel Technique to Synthesis of (Cu,Co)3O4 Spinel on Ferritic Stainless Steel used for Solid Oxide Fuel Cell Interconnects
, M.Sc. Thesis Sharif University of Technology ; Askari, Masoud (Supervisor)
Abstract
Due to recent progresses in lowering the temperature of SOFC, using metallic interconnects instead of ceramic interconnects was possible. Among the alloys used for interconnects, ferritic stainless steels (FSS) due to thermal expansion coefficient compatible with other cell components and cheap fabrication, have become the most widely used material for interconnects. Because of improvement of oxidation resistance of these FSSs, many studies have been made on coating of oxides on FSSs and results show that the spinel oxides have the best performance. In this study, the CuCo2O4 performance as coating in SOFC's interconnects was investigated. Coating process used was sol-gel dip coating and raw...
Lithium Recovery from Brine Sources of Iran by Precipitation Method
, M.Sc. Thesis Sharif University of Technology ; Askari, Masoud (Supervisor)
Abstract
Lithium is one of the most commonly used metals in industry with a wide variety of applications including batteries, lubricating grease and pharmaceutical products. Demand for lithium is expected to rise with the increasing adoption of electric vehicles. Market reports have predicted that world lithium demand will increase by 2.5 times from 2010 to 2020. Therefore, there is a pressing need to develop new sources of lithium to support this anticipated increase in demand. Lithium can be extracted from salt brine and lithium containing minerals as lithium compounds.
Salt brines are the most abundant lithium sources available in the world, comprising about 60% of all known lithium deposits....
Salt brines are the most abundant lithium sources available in the world, comprising about 60% of all known lithium deposits....
Kinetics Investigation of the Degradation of Environmental Pollutants by Fenton and Electro-Fenton Processes using Nanomagnetite and Nano Magnetite Supported by Activated Carbon
, M.Sc. Thesis Sharif University of Technology ; Rahmansetayesh, Shahrbano (Supervisor)
Abstract
The progress and the development of various industries, pollutants derived from the agricultural and industrial processes contaminate the environment. The degradation of these pollutants have an important effect on the environment.Magnetite (Fe3O4) nanoparticles and magnetite supported on functionalized activated carbon were synthesized and characterized by different techniques such as SEM, FT-IR, XRD, BET and VSM. The catalyst activity of these nanocatalysts was evaluated by the degradation of reactive red ME4BL (RRME4BL) textile dye in heterogeneous Fenton and electro-Fenton processes as a model pollutant. The effect of several parameters such as H2O2, RRME4BL concentration, the amount of...
“Cold Briquetted Iron and Carbon (CBIC)”, Investigation of Oxidation Behavior in Environmental Conditions and Steelmaking Performance
,
Ph.D. Dissertation
Sharif University of Technology
;
Askari, Masoud
(Supervisor)
Abstract
Cold Briquetted Iron and Carbon (CBIC) is a new product in Direct Reduced Iron (DRI) family that aims to produce a reliable product from Cold Direct Reduced Iron (CDRI) with the ability of low risk, high efficient storage and handling. In this study, a comprehensive investigation was carried out on the effects of environmental condition on physical and chemical properties of CBIC, CDRI and Hot Briquetted Iron (HBI) in the first step and then, the steelmaking performance of this new product was compared to the other DRI products in the second step. The changes of microstructure, specific surface area, metallization degree and mechanical strength of different products with time in dry and...
Energy harvesting from structural vibrations of magnetic shape memory alloys
, Article Applied Physics Letters ; Volume 110, Issue 10 , 2017 ; 00036951 (ISSN) ; Cottone, F ; Sayyaadi, H ; Zakerzadeh, M. R ; Orfei, F ; Gammaitoni, L ; Sharif University of Technology
American Institute of Physics Inc
2017
Abstract
This letter presents the idea of scavenging energy from vibrating structures through magnetic shape memory alloy (MSMA). To this end, a MSMA specimen made of Ni50Mn28Ga22 is coupled to a cantilever beam through a step. Two permanent magnets installed at the top and bottom of the beam create a bias field perpendicular to the magnetization axis of the specimen. When vibrating the device, a longitudinal axial load applies on the MSMA, which in turn changes the magnetization, due to the martensitic variant reorientation mechanism. A pick-up coil wounded around the MSMA converts this variation into voltage according to the Faraday's law. Experimental test confirms the possibility of generating...
A novel approach for energy and water conservation in wet cooling towers by using MWNTs and nanoporous graphene nanofluids
, Article Energy Conversion and Management ; Volume 109 , 2016 , Pages 10-18 ; 01968904 (ISSN) ; Lotfi, R ; Seif Kordi, A ; Rashidi, A. M ; Koolivand, H ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
This study deals with an experimental investigation on the thermal performance of a mechanical wet cooling tower with counter flow arrangement by using multi-walled carbon nanotubes (MWNTs) and nanoporous graphene nanofluids. Stable nanofluids were prepared through two-step procedure by using water with properties taken from a working cooling tower in the South of Iran. Zeta potential revealed suitable stability of MWNTs and nanoporous graphene nanofluids. Thermal and rheological properties of the nanofluids were investigated. It was found that thermal conductivity increases by 20% and 16% at 45°C for MWNTs and nanoporous graphene nanofluids, respectively. The increase in density and...
Fabrication of Mn/Co and Co Coatings on AISI 430 for SOFC Interconnect Via Sol-Gel and Dip Coating
, M.Sc. Thesis Sharif University of Technology ; Askari, Masoud (Supervisor)
Abstract
With regard to recent progress in decreasing of operating temperature of Solid Oxide Fuel Cell (SOFC), metallic interconnect use widely than ceramic interconnect. Metallic interconnect have interested due to their low cost, easy fabrication and high electronic and thermal conductivity.oxidation resistance of metals is big challenge, because of low conductivity of formed oxide layers that led to increasing of electrical conductivity. Ferritic stainless steel is among the most thriving candidate alloy because of BCC structure that its coefficient of temperature expansion is close to that of other SOFC. Nonetheless, the increase of electrical resistance over the time and the evaporation of...