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Lattice Boltzmann simulation of TiO2-water nanofluid in a curved boundary domain at high Rayleigh numbers
, Article Computers and Fluids ; Volume 168 , 30 May , 2018 , Pages 159-169 ; 00457930 (ISSN) ; Saidi, M. H
Elsevier Ltd
2018
Abstract
In this paper, a two-component Lattice Boltzmann Method (LBM) has been utilized to simulate the natural convection of TiO2-water nanofluid in a curved geometry. The main purpose of this research is to study the effect of nanoparticle size and also boundary conditions on the thermal characteristics of the nanofluid. Furthermore, the effect of Rayleigh number (Ra) and volume fraction of nanoparticles (ϕ) on the average Nusselt number (Nuave) have been investigated. Two different thermal boundary conditions, namely adiabatic and constant temperature, have been considered in the current work for the curved boundaries. The Rayleigh number varies from 103 to 109. Four different sizes, namely 10,...
LBM investigation of a Cu-water nanofluid over various configurations of pipes in the mixed convection flow
, Article Heat Transfer ; Volume 50, Issue 2 , August , 2021 , Pages 1056-1072 ; 26884534 (ISSN) ; Sharif University of Technology
John Wiley and Sons Inc
2021
Abstract
Increasing the heat capacity of heat exchangers is a crucial need for modern devices. The thermal conductivity of the usual fluids and the Nusselt (Nu) number of flows containing such fluids are two bottlenecks in the way of increasing heat delivery in the heat exchangers. For this reason, nanofluids have been introduced. The effect of utilizing a Cu-water nanofluid as a coolant of two hot pipes in a square cavity is investigated numerically with a two-component lattice Boltzmann method. The volume fraction of nanoparticles is assumed to be constant (0.03) while the Richardson (Ri) number varies from 0.02 to 20. Results show that the effectiveness of nanoparticles is better observed in the...
Simulation of natural convection of nanofluids at high rayleigh numbers: A two-component lattice Boltzmann study
, Article Computational Thermal Sciences ; Volume 8, Issue 1 , 2016 , Pages 31-47 ; 19402503 (ISSN) ; Saidi, M. H ; Sharif University of Technology
Begell House Inc
2016
Abstract
In this research, the effect of using nanoparticles on the Nusselt number in the natural convection at high Rayleigh numbers has been investigated. A two-component multiple relaxation times lattice Boltzmann code has been developed to investigate the natural convection of nanofluids in a 2D square enclosure. Three main forces, namely, buoyancy, drag, and Brownian forces are included to consider the interactions of the components. The potential force is also added to the model for the interactions among nanoparticles. The effects of Ra number, volume fraction of nanoparticles (ϕ), and size of nanoparticles (λ) have been investigated for two nanofluids (CuO-water and TiO2-water). Five...
3D investigation of natural convection of nanofluids in a curved boundary enclosure applying lattice Boltzmann method
, Article International Journal of Numerical Methods for Heat and Fluid Flow ; Volume 28, Issue 8 , 2018 , Pages 1827-1844 ; 09615539 (ISSN) ; Saidi, M. H ; Sharif University of Technology
Emerald Group Publishing Ltd
2018
Abstract
Purpose: The purpose of this paper is to investigate the natural convection behavior of nanofluids in an enclosure. The enclosure is a 3D capsule with curved boundaries filled with TiO2-water nanofluid. Design/methodology/approach: In this paper, a multiple relaxation times lattice Boltzmann method (MRT-LBM) has been used. Two-component LBM has been conducted to consider the interaction forces between nanoparticles and the base fluid. Findings: Results show that the enhanced Nusselt number (Nu*) increases with the increase in volume fraction of nanoparticles (ϕ) and Ra number and decrease of nanoparticle size (λ). Additionally, the findings indicate that increasing volume fraction beyond a...
Numerical simulation of MHD mixed convection flow of Al2O3–water nanofluid over two hot obstacles
, Article Heat Transfer ; Volume 51, Issue 4 , 2022 , Pages 3237-3256 ; 26884534 (ISSN) ; Saidi, M. H ; Sharif University of Technology
John Wiley and Sons Inc
2022
Abstract
The problem of cooling two hot blocks in a novel geometry using magnetohydrodynamic flow of Al2O3–water nanofluid has been studied utilizing a D2Q9 Lattice Boltzmann Model. While the Hartmann number (Ha) takes 0, 50, or 100 values, the Richardson number (Ri) varies between 0.02 and 20. Four variations of the geometry are selected. The gravity angle is set to be either (Formula presented.), (Formula presented.), or (Formula presented.). Results reveal that the Nusselt number (Nu) increases as Ri increases for all cases. Furthermore, the Hartmann number has a deteriorating effect on the Nusselt number except for low Ri numbers. In addition, the results indicate that while the geometrical...
Modeling and Performance Investigation of Airlift Pump with Conical Upriser Pipe
, M.Sc. Thesis Sharif University of Technology ; Saeedi, Mohammad Hassan (Supervisor)
Abstract
Airlift pumps are widely used in numerous industries for different applications such as transmission of viscous fluids (heavy hydrocarbons of oil), pumping of corrosive liquids and so on. In general, parameters which affect the efficiency of an airlift pump can be classified into two major groups. The first group is the designing parameters such as the diameter of the upriser pipe or the submergence ratio. The second group is the operation parameters such as diameter of the bubble, inlet pressure of the gas and so on. One of the designing parameters which can have an effective influence on the performance of an airlift pump is the non-constant diameter of the upriser pipe, which can be...
Two-phase, Two-component Simulation of Nanofluids in Natural Convection Applying Lattice Boltzmann Method
, Ph.D. Dissertation Sharif University of Technology ; Saeedi, Mohammad Hassan (Supervisor)
Abstract
The advances of technology of microelectrical devices and their computational capacity and so, their heat rates, make the thermal control of them more complex. Utilizing nanopfluids is one of proposing options. The current research investigates the effectiveness of using nanoparticles on the heat transfer rate of fluids in the natural convection. A two-component two-phase lattice Boltzmann method (LBM) has been implemented for this purpose. A wide range of Rayleigh number (Ra), namely 103 to 109, 0 to 0.05 volume fraction s of nanoparticles and nanoparticle diameters below 100 nm has been investigated in this research. The method is optimized for complex geometries. Two and three dimensional...
L-lysine biodetector based on a TOCNFs-coated Quartz Crystal Microbalance (QCM)
, Article European Polymer Journal ; Volume 186 , 2023 ; 00143057 (ISSN) ; Iraji zad, A ; Vossoughi, M ; Hosseini, M ; Sharif University of Technology
Elsevier Ltd
2023
Abstract
Developing a simple, cost effective and accurate detection method for L-lysine (Lys), L-leucine (Leu) and glycine (Gly) as the important analytes in clinical diagnostics, biological processes and food industries is of great significance. Herein, we prepared spin-coated TEMPO-oxidized cellulose nanofibrils (TOCNFs) on Quartz Crystal Microbalance (QCM) chip to achieve QCM biodetectors. The coated QCMs were carefully characterized before and after interaction with amino acids (AA) using water contact angle (WCA), Fourier transform infrared spectrophotometry-attenuated total reflectance (FTIR-ATR), Raman spectroscopy, and scanning electron microscopy (SEM). In addition, to study the response of...
Experimental and numerical fatigue life study of cracked AL plates reinforced by glass/epoxy composite patches in different stress ratios
, Article Mechanics Based Design of Structures and Machines ; Volume 49, Issue 6 , 2021 , Pages 894-910 ; 15397734 (ISSN) ; Safarabadi, M ; Ganjiani, M ; Mohammadi, E ; Hosseini, A ; Sharif University of Technology
Bellwether Publishing, Ltd
2021
Abstract
In this study, the fatigue behavior of composite reinforced cracked aluminum 1050 plates is investigated experimentally and numerically. The tests are conducted in four different stress ratios between 0 and 1. At first step, plates with similar cracks and geometries have been prepared. Then the glass/epoxy patches have been attached to the cracked plates using Araldite 2015 adhesive. Fatigue load has been applied to three cases of samples including non-patch, one-side patch and two-side patch, where in all stress ratios the maximum force is considered constant. A three-dimensional finite element analysis is developed in ABAQUS. A good correlation between finite element results and the...
Monte Carlo simulation of Feynman-α and Rossi-α techniques for calculation of kinetic parameters of Tehran research reactor
, Article Annals of Nuclear Energy ; Volume 38, Issue 10 , 2011 , Pages 2140-2145 ; 03064549 (ISSN) ; Vosoughi, N ; Hosseini, M ; Sharif University of Technology
2011
Abstract
Noise analysis techniques including Feynman-α (variance-to-mean) and Rossi-α (correlation) have been simulated by MCNP computer code to calculate the prompt neutron decay constant (α0), effective delayed neutron fraction (βeff) and neutron generation time (Λ) in a subcritical condition for the first operating core configuration of Tehran Research Reactor (TRR). The reactor core is considered to be in zero power (reactor power is less than 1 W) in the entire simulation process. The effect of some key parameters such as detector efficiency, detector position and its dead time on the results of simulation has been discussed as well. The results of proposed method in the current study are...
Facial mark detection and removal using graph relations and statistics
, Article 2017 25th Iranian Conference on Electrical Engineering, ICEE 2017, 2 May 2017 through 4 May 2017 ; 2017 , Pages 2223-2228 ; 9781509059638 (ISBN) ; Jamzad, M ; Sharif University of Technology
2017
Abstract
Face Analysis is an important task in image processing. Most of these tasks centralized on face recognition and detection. One of different ways for deceiving automatic face analysis systems is mark notation on the skin. On the other hand some applications attempts to eliminate defects of the face. Hence, in this paper we try to detect and remove skin marks on the face, whether they're natural or not. Our algorithm passes face image through appropriate filters to get mark candidates and then create a graph space using 8-point neighborhood relations of mark candidates image pixels. Then we compute probabilities of each mark candidate using four measures based on intensity of occurrence, shape...
Calculation of fuel burn up and radioactive inventory for HEU fuel element of Tehran Research Reactor
, Article International Conference on Nuclear Engineering, Proceedings, ICONE, 17 May 2010 through 21 May 2010 ; Volume 2 , 2010 ; 9780791849309 (ISBN) ; Vosoughi, N ; Hosseini, M ; Nuclear Engineering Division ; Sharif University of Technology
2010
Abstract
This paper presents a new approach for fuel burn up evaluation and radioactive inventory calculation used in Tehran Research Reactor. The approach is essentially based upon the utilization of a program written by C# which integrates the cell and core calculation codes, i.e., WIMSD-4 and CITVAP, respectively. Calculation of fuel burn up and radioactive inventories has been done for 26 core configuration of Tehran Research Reactor with HEU fuel element. The present inventory and fuel enrichment of each fuel element have been calculated
Phase diagram of the strongly correlated Kane-Mele-Hubbard model
, Article Physical Review B - Condensed Matter and Materials Physics ; Volume 85, Issue 19 , 2012 ; 10980121 (ISSN) ; Mashkoori, M ; Hosseini, M ; Sharif University of Technology
2012
Abstract
The phase diagram of the strongly correlated Hubbard model with intrinsic spin-orbit coupling on the honeycomb lattice is explored here. We obtain the low-energy effective model describing the spin degree of freedom. The resulting model is then studied by the Schwinger boson and Schwinger fermion approaches. The Schwinger boson method elucidates the boundary between the spin liquid phase and the magnetically ordered phases, Neel order, and incommensurate Neel order. Increasing the strength of the spin-orbit coupling is shown to narrow the width of the spin liquid region. The Schwinger fermion approach sheds further light on the nature of the spin liquid phase. We obtained three different...
Study of 2-butyne-1,4-diol as acid corrosion inhibitor for mild steel with electrochemical, infrared and AFM techniques
, Article International Journal of Electrochemical Science ; Volume 4, Issue 9 , 2009 , Pages 1339-1350 ; 14523981 (ISSN) ; Arshadi, M. R ; Sharif University of Technology
2009
Abstract
The inhibition of mild steel corrosion in 0.5 M sulphuric acid by the symmetrical acetylenic alcohol 2- butyne-1,4-diol is investigated. Weight loss and electrochemical impedance data consistently indicate inhibition efficiencies up to 98%. Short-term impedance measurements reveal that the interfacial inhibition is a function of the exposure time, and that full performance is achieved faster as inhibitor concentration and temperature are higher. An infrared study of the surface film provides evidence that the film does not achieve its final state but after several hours. Atomic force Microscopy has been used for investigation the surface topography of metallic electrode. © 2009 by ESG
Seismic performance of an innovative structural system having seesaw motion and columns equipped with friction dampers at base level
, Article Structural Design of Tall and Special Buildings ; 2016 ; 15417794 (ISSN) ; Fekri, M ; Yekrangnia, M ; Sharif University of Technology
John Wiley and Sons Ltd
2016
Abstract
Most seismic design codes accept heavy damages to buildings in case of large earthquakes, provided that they are prevented against collapse. However, this leads to unacceptable consequences, such as very large volume of the required reconstruction works, in large populated cities. One way to get rid of these adverse consequences is using the idea of combining rocking/seesaw motion of the building's structure and energy dissipation at base level to create buildings easily repairable even after a large earthquake. In the present study, this idea has been employed for designing steel buildings with seesaw motion capability by using a central massive column at ground floor, with elastic behavior...
A new microstructural model based on dislocation generation and consumption mechanisms through severe plastic deformation
, Article Computational Materials Science ; Volume 50, Issue 3 , January , 2011 , Pages 1123-1135 ; 09270256 (ISSN) ; Kazeminezhad, M ; Sharif University of Technology
2011
Abstract
A new model on the evolution of dislocation structure of cell forming metals and alloys through severe plastic deformation is presented. Following previous approaches, the model considers a cellular dislocation structure consisted of two phases: cell interiors and cell walls. The model distinguishes edge and screw dislocations in terms of three categories: mobile dislocations, immobile dislocations in cell interiors and immobile dislocations in cell walls. Then considering physical and geometrical assumptions for each dislocation category, an evolutional law is derived, based on some dislocation interaction mechanisms such as dislocation generation, annihilation, locking and migration. The...
Implementation of a constitutive model in finite element method for intense deformation
, Article Materials and Design ; Volume 32, Issue 2 , February , 2011 , Pages 487-494 ; 02641275 (ISSN) ; Kazeminezhad, M ; Sharif University of Technology
2011
Abstract
Since the constitutive information is one of the most important aspects of material deformation analysis, here a new constitutive model is proposed that can investigate the behavior of material during intense deformation better than existent models. The model that is completely based on physical mechanisms can predict all stages of flow stress evolution and also can elucidate the effects of strain and strain rate on flow stress evolution of material during intense plastic deformation. Here as an application, implementation of the constitutive model in finite element method (FEM) is used to compare two methods of sever plastic deformation (SPD) processes of copper sheet; repetitive...
A dislocation-based model considering free surface theory through HPT process: Nano-structured Ni
, Article Scientia Iranica ; Volume 17, Issue 1 F , 2010 , Pages 52-59 ; 10263098 (ISSN) ; Kazeminezhad, M ; Sharif University of Technology
2010
Abstract
In this study, a dislocation-based model is presented for investigating the evolution of micro structure and mechanical properties of thin films during a wide range of straining. The model is applied to the High Pressure Torsion (HPT) process of thin nickel disks that provides valuable information on the evolution of material parameters during deformation. The model considers a free surface theory for thin films and can explain the size effect phenomenon in agreement with previous reported trends in literature
Retraction notice to "Nano-structure and mechanical properties of 0-7 strained aluminum by CGP: XRD, TEM and tensile test" [Mater. Sci. Eng. A 526, (2009) 219-224]
, Article Materials Science and Engineering A ; Volume 640 , July , 2015 , Pages 480- ; 09215093 (ISSN) ; Kazeminezhad, M ; Sharif University of Technology
Elsevier Ltd
2015
Integration of physically based models into FE analysis: Homogeneity of copper sheets under large plastic deformations
, Article Computational Materials Science ; Volume 48, Issue 1 , 2010 , Pages 166-173 ; 09270256 (ISSN) ; Kazeminezhad, M ; Sharif University of Technology
2010
Abstract
In this paper, an integration approach consists of implementation of true internal state variables constitutive model to finite element (FE) analysis is presented. From the approach, the deformation homogeneity during severe plastic deformation of sheet (SPD) is investigated. Since there is not any constitutive model for large deformation that based on appropriated physical assumptions, here a new constitutive model is proposed that is entirely based on metallurgical mechanisms. Also, in order to achieve accurate results with low computation time, a new approach for integration of the constitutive model to FE analysis is presented. By coupling the constitutive model and FE analysis, the...