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Numerical study of heat and mass transfer in underexpanded sonic free jet
, Article International Journal of Heat and Technology ; Volume 35, Issue 4 , 2017 , Pages 959-968 ; 03928764 (ISSN) ; Farhanieh, B ; Afshin, H ; Sharif University of Technology
2017
Abstract
In case of unexpected ruptures in high pressure tanks, choking phenomenon occurs in the cracked area which fluid velocity gets sonic and its pressure exceeds atmospheric pressure. Afterward, pressure of discharged gas quickly changes by crossing through compression and expansion shock waves. The main aim of this study was numerical simulation and investigation of this flow in a 3-step process: (a) Detailed analysis of numerical method, (b) Qualitative and quantitative analysis of velocity, pressure, temperature and turbulence intensity, in order to propose safety strategies and (c) parametric studies on the effects of tank pressure and nozzle geometry on flow structure. In numerical...
Synthesis and analysis of the properties of ferro-fluids
, Article ICONN 2010 - Proceedings of the 2010 International Conference on Nanoscience and Nanotechnology, 22 February 2010 through 26 February 2010, Sydney, NSW ; 2010 , Pages 91-93 ; 9781424452620 (ISBN) ; Ghane Motlagh, B ; Ghane Golmohamadi, F ; Ghane Motlagh, R ; Rouhani, S ; Sharif University of Technology
2010
Abstract
We report the rheological properties of ferro-fluid (FF) containing iron oxide nano-particles. At first, a FF was synthesized by using chemical co-precipitaton[1]. The microstructure study using SEM revealed that the FF contained nano-particles with the mean particle size of 35nm. The XRD study revealed that we have well crystallized structures of magnetite; they appeared to be approximately single crystalline structures. The rheological results proved that the FF has non Newtonian behavior, it is a shear thinning fluid in all magnetic fields, Moreover, the magnetic field increases the viscosity in a definite shear rate due to the nano-particles agglomerations and formation of chain-like...
A characteristic-based numerical simulation of water-titanium dioxide nano-fluid in closed domains
, Article International Journal of Engineering, Transactions A: Basics ; Volume 33, Issue 1 , 2020 , Pages 158-163 ; Razavi, S. E ; Adibi, O ; Sharif University of Technology
Materials and Energy Research Center
2020
Abstract
A new characteristic-based method is developed and used for solving the mixed and forced convection problems. The nano-fluid flow with heat transfer is simulated with a novel characteristic-based scheme in closed domains with different aspect ratios. For this purpose, a FORTRAN code has been written and developed. Water as a pure fluid and water-titanium dioxide as a nano-fluid were considered. The governing equations are solved by the finite volume utilizing a characteristic-based scheme for the convective fluxes. The simulation is done at Grashof numbers from 100 to 104, Reynolds numbers from 100 to 1000, and volume fractions of nano-particles from 0% to 10%. Streamlines, isotherms,...
A parametric study on the effects of surface explosions on buried high pressure gas pipelines
, Article Engineering Solid Mechanics ; Volume 5, Issue 4 , 2017 , Pages 225-244 ; 22918744 (ISSN) ; Azadi, A ; Farhanieh, B ; Afshin, H ; Sharif University of Technology
Growing Science
2017
Abstract
Underground gas pipelines are one of the vital parts of each country which surface blasts can break down such pipelines, making destructive explosions and threatening the safety of neighborhood structures and people. In this paper, to enhance the safety of these lines, response of a buried 56-inch diameter high pressure natural gas pipeline to a surface blast was numerically investigated. Besides, the effects of: i) explosive mass, ii) pipeline thickness, iii) burial depth and iv) concrete protective layer on pipeline deformation were parametrically studied. To simulate the problem according to actual explosion events, geometries were modeled in real scales, pipeline properties were...
CFD simulation of airflow in the side-platform stations
, Article MATEC Web of Conferences, 20 July 2015 through 21 July 2015 ; Volume 28 , 2015 ; 2261236X (ISSN) ; Farhanieh, B ; Afshin, H ; Wei-Hsin L ; Zhihua G ; Sharif University of Technology
EDP Sciences
2015
Abstract
Design of an appropriate ventilation system is one of the main concerns in the construction of subways. In this paper, thermal comforts of side-platform stations are investigated by numerical methods. For the numerical simulation, grids are generated by structured methods and governing equations are discretized by finite volume methods. In the numerical simulation, second order upwind and second order central difference scheme are used to consider the convection and diffusion terms of momentum and energy equations, respectively. Results of this study show that in term of thermal comfort, region next to the hallway and the middle part of the platform is the worst zones of the station. In...
Immobilization of modular peptides on graphene cocktail for differentiation of human mesenchymal stem cells to hepatic-like cells
, Article Frontiers in Chemistry ; Volume 10 , 2022 ; 22962646 (ISSN) ; Hashemi, E ; Akhavan, O ; Khezri, J ; Rezaei, A ; Zamani Amir Zakria, J ; Siadat, S. D ; Sahebghadam Lotfi, A ; Farmany, A ; Sharif University of Technology
Frontiers Media S.A
2022
Abstract
In this study, two novel biomimetic modular peptide motifs based on the alpha-2 subunit of type IV collagen (CO4A2) were designed and immobilized on a graphene platform to imitate integrin and heparan sulfate- (HS-) binding proteins. The in silico study was used to design 9-mer K[KGDRGD]AG and 10-mer KK[SGDRGD]AG for testing designed Integrin-Binding Peptide (dIBP) and HS-Binding Peptide (dHBP). The virtual docking technique was used to optimize the peptide motifs and their relevant receptors. Molecular dynamic (MD) simulation was used to evaluate the stability of peptide-receptor complexes. The effect of the platform on the differentiation of human mesenchymal stem cells (hMSCs) to...
Plasmonic propagation modes of a structured two-dimensional conducting interface
, Article Journal of Optics A: Pure and Applied Optics ; Volume 10, Issue 2 , 2008 ; 14644258 (ISSN) ; Khorasani, S ; Hosseini, A ; Mehrany, K ; Rashidian, B ; Adibi, A ; Sharif University of Technology
2008
Abstract
In this paper, we present a detailed analysis of a two-dimensional lossless and non-dispersive structured conducting interface, which is approximated by a two-dimensional ideal one-component plasma-like conducting sheet enclosed by two isotropic dielectrics. We present a Green's function formalism to analyze the propagation of surface plasmons and find new expressions. We also present analytical extensions of the approach to include loss, and discuss the results and applications of the theory. We study the symmetry properties of eigenmodes and show that the symmetries of the eigenmodes at high-symmetry points of the Brillouin zone are similar to those of the E-polarization eigenmodes of a...
Nanomagnetic NH2·MIL-101(Fe)/ED as a new highly efficient catalyst for the synthesis of thiopyran and oxospiro-indolinethiopyran derivatives
, Article Journal of Sulfur Chemistry ; Volume 44, Issue 6 , 2023 , Pages 666-682 ; 17415993 (ISSN) ; Aghamiri, B ; Yazdani Motlagh, A ; Jarahiyan, A ; Sharif University of Technology
Taylor and Francis Ltd
2023
Abstract
In this publication, we reported an efficient MOF-based catalytic system for the synthesis of thiopyran and oxospiro-indolinethiopyran derivatives. For the first time, magnetic NH2.MIL-101(Fe)/ED was synthesized through anchoring FeCl3 on CoFe2O4 magnetic nanoparticles surface and then 2-aminoterphthalic acid was used to form MOF structure. In the final step, metal centers were modified with ethylenediamine (ED). Different techniques such as Fourier transmission infrared spectroscopy, X-ray diffraction, Field emission scanning electron microscopy, Transmission electron microscopy, Brunauer–Emmett–Teller analysis, and Thermogravimetric analysis were used to characterize the catalyst...
Design and fabrication of photonic crystal nano-beam resonator: transmission line model
, Article Journal of Lightwave Technology ; Volume 32, Issue 1 , 14 November 2013 , Pages 91-98 ; Sodagar, M ; Mehrany, K ; Eftekhar, A. A ; Adibi, A ; Rashidian, B ; Sharif University of Technology
14 November 2013
Abstract
We present a new method for modeling and design of photonic crystal nano-beam resonators (PCNBRs) based on cascaded transmission lines. The proposed model provides an accurate estimate of the PCNBRs properties such as resonance wavelength and quality factor (Q) with much smaller computation cost as compared to the brute-force numerical methods. Furthermore, we have developed a straightforward technique for the design of high-Q PCNBRs based on resonance modes with Gaussian electromagnetic field profiles. The results obtained by using the proposed transmission line model are compared against numerical and experimental results and the accuracy of the model is verified. The proposed model...
Wideband tunable photonic crystal cavity with electrostatic actuation
, Article 2012 IEEE Photonics Conference, IPC 2012, 23 September 2012 through 27 September 2012 ; September , 2012 , Pages 266-267 ; 9781457707315 (ISBN) ; Sodagar, M ; Eftekhar, A. A ; Mehrany, K ; Rashidian, B ; Adibi, A ; Sharif University of Technology
2012
Abstract
We present a wideband tunable optical cavity based on electrostatic actuation. Over 60nm shift in wavelength is achieved by applying less than 1 Volt corresponds to a mechanical displacement of 30nm
Analytical analysis of H polarized line-defect modes in two-dimensional photonic crystals based on hermite expansion of floquet orders
, Article Photonic Crystal Materials and Devices VI, San Jose, CA, 22 January 2007 through 25 January 2007 ; Volume 6480 , 2007 ; 0277786X (ISSN) ; Atabaki, A. H ; Mehrany, K ; Khorasani, S ; Rashidian, B ; Adibi, A ; Sharif University of Technology
2007
Abstract
Using polynomial expansion of electromagnetic fields has been already reported for extraction of E polarized defect modes in two-dimensional photonic crystals. This approach is now applied to straight single-line defect optical waveguides, where H polarized defect modes are analytically extracted for the first time. Electromagnetic fields are expanded in accordance with the Floquet theorem, where each Floquet order is itself expanded in terms of Hermite polynomials and finally a new set of linear ordinary differential equations with non-constant coefficients is obtained. This set of equations is handled by employing differential transfer matrix method. In this fashion, algebraic and easy to...
Laminar forced convection simulation at different boundary conditions with averaging scheme (numerical and theoretical research)
, Article Mathematical Modelling of Engineering Problems ; Volume 6, Issue 4 , 2019 , Pages 519-526 ; 23690739 (ISSN) ; Adibi, O ; Sharif University of Technology
International Information and Engineering Technology Association
2019
Abstract
In this paper, cavity flow is simulated numerically. Forced convection in different Reynolds numbers between 100 and 5000 is simulated. Different and complex thermal boundary conditions are applied and various parameters are calculated numerically. Up and down walls are in constant temperature and left and right walls are thermal insulation in the first thermal boundary condition. The Left and the down walls are in constant temperature and the temperature of the up and the right walls changes linearly in the second thermal boundary condition. For the third thermal boundary condition, the left and the down walls are in constant temperature and the temperature of the up and the right walls...
Laminar forced convection simulation at different boundary conditions with averaging scheme (numerical and theoretical research)
, Article Mathematical Modelling of Engineering Problems ; Volume 6, Issue 4 , 2019 , Pages 519-526 ; 23690739 (ISSN) ; Adibi, O ; Sharif University of Technology
International Information and Engineering Technology Association
2019
Abstract
In this paper, cavity flow is simulated numerically. Forced convection in different Reynolds numbers between 100 and 5000 is simulated. Different and complex thermal boundary conditions are applied and various parameters are calculated numerically. Up and down walls are in constant temperature and left and right walls are thermal insulation in the first thermal boundary condition. The Left and the down walls are in constant temperature and the temperature of the up and the right walls changes linearly in the second thermal boundary condition. For the third thermal boundary condition, the left and the down walls are in constant temperature and the temperature of the up and the right walls...
Simulation of New Methods in Ventilation of Underground Station Sand Tunnels
, M.Sc. Thesis Sharif University of Technology ; Farhanieh, bijan (Supervisor)
Abstract
Due to growth of the number of passengers in subway transportation systemsthe capacity of the metro stations are on the rise.The generated heat loads in subway line shall be increased by thegrowth of the its capacity. As a result, current subway ventilation systems cannot provide comfort conditions for passengers. Nowadays, modern ventilation systems are designedto improve ventilation performance and to create suitable thermal conditions. Among of these, the under platform andover track exhaust systems and use of platform screen doors can be Cited. The aim of this study is three-dimensional simulation of air flow in modern ventilation systems of subway stations. Numerical simulations are in...
Mott Transition in Ordered and Disordered Honeycomb Lattice Using Strong-coupling Perturbation Theory
, Ph.D. Dissertation Sharif University of Technology ; Jafari, Akbar (Supervisor)
Abstract
The ability to determine the nature of the low temperature state of the interacting quantum system is one of the main goals of condensed matter theory. Nevertheless, despite ongoing efforts, no single method has proved to work perfectly for interacting systems. In this thesis, we employ the strong-coupling perturbation theory which corresponds to an expansion in powers of the hopping t around the atomic limit. So, first the strong-coupling perturbation theory is introduced. Next we apply this approach to the half-filled Hubbard model on honeycomb lattice. Within this approach, we are able to obtain an analytical form for single-particle gap, extracted from density of state, as a function of...
Fractal flow of inhomogeneous fluids over smooth inclined surfaces and determination of their fractal dimensions and universality classes
, Article Journal of Physics Condensed Matter ; Volume 17, Issue 14 , 2005 , Pages S1219-S1227 ; 09538984 (ISSN) ; Ghane Motlagh, B ; Baradaran, S ; Shekarian, E ; Rouhani, S ; Sharif University of Technology
2005
Abstract
Patterns formed by the flow of an inhomogeneous fluid (suspension) over a smooth inclined surface were studied. It was observed that fractal patterns are formed. There exists a threshold angle for the inclination above which global fractal patterns are formed. This angle depends on the particle size of the suspension. We observed that there are two fractal dimensions for these patterns, depending on the area from which the pattern is extracted. If the pattern is taken from the top which only consists of the beginning steps of the pattern forming, one finds two fractal dimensions, i.e. 1.35-1.45 and 1.6-1.7, in which the first one is dominant. And if the entire pattern is taken, then fractal...
Fractal behaviour of flow of inhomogeneous fluids over smooth inclined surfaces
, Article Journal of Physics Condensed Matter ; Volume 16, Issue 15 , 2004 , Pages 2497-2505 ; 09538984 (ISSN) ; Ghane Motlagh, B ; Baradaran, S ; Shekarian, E ; Rouhani, S ; Sharif University of Technology
2004
Abstract
Patterns formed by the flow of an inhomogeneous fluid (suspension) over a smooth inclined surface were studied. It was observed that fractal patterns form. There exists a threshold angle for the inclination above which global fractal patterns are formed. This angle depends on the particle size of the suspension. We observed that there are two fractal dimensions for these patterns, depending on the area from which the pattern is extracted. If the pattern is taken from the top which only consists of the beginning steps of the pattern forming, one finds two fractal dimensions, i.e. 1.35-1.45 and 1.6-1.7, in which the first one is dominant while, if the entire pattern is taken, then a fractal...
Strong-coupling approach to mott transition of massless and massive Dirac fermions on honeycomb lattice
, Article Physical Review B - Condensed Matter and Materials Physics ; Volume 93, Issue 7 , 2016 ; 10980121 (ISSN) ; Jafari, S. A ; Sharif University of Technology
American Physical Society
2016
Abstract
Phase transitions in the Hubbard model and ionic Hubbard model at half-filling on the honeycomb lattice are investigated in the strong-coupling perturbation theory which corresponds to an expansion in powers of the hopping t around the atomic limit. Within this formulation we find analytic expressions for the single-particle spectrum, whereby the calculation of the insulating gap is reduced to a simple root finding problem. This enables high-precision determination of the insulating gap that does not require any extrapolation procedure. The critical value of Mott transition on the honeycomb lattice is obtained to be Uc≈2.38t. Studying the ionic Hubbard model at the lowest order, we find two...
A note on isometries of Lipschitz spaces
, Article Journal of Mathematical Analysis and Applications ; Vol. 411, Issue. 2 , 2014 , Pages 555-558 ; ISSN: 0022247X ; Sharif University of Technology
2014
Abstract
The main purpose of this article is to generalize a recent result about isometries of Lipschitz spaces. Botelho, Fleming and Jamison [2] described surjective linear isometries between vector-valued Lipschitz spaces under certain conditions. In this article, we extend the main result of [2] by removing the quasi-sub-reflexivity condition from Banach spaces
An integral type characterization of constant functions on metric-measure spaces
, Article Journal of Mathematical Analysis and Applications ; Volume 385, Issue 1 , January , 2012 , Pages 194-201 ; 0022247X (ISSN) ; Sharif University of Technology
2012
Abstract
The main purpose of this article is to generalize a characterization of constant functions to the context of metric-measure spaces. In fact, we approximate a measurable function, in terms of a certain integrability condition, by Lipschitz functions. Then, similar to Brezis (2002) [2], we establish a necessary and sufficient condition in order that any measurable function which satisfies an integrability condition to be constant a.e. Also, we provide a different proof for the main result of Pietruska-Pałuba (2004) [7] in the setting of Dirichlet forms