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porous-materials
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Numerical Study of the Effect of Permeability in Single-Phase Flow in Porous Media
, M.Sc. Thesis Sharif University of Technology ; Sadrhosseini, Hani (Supervisor) ; Ashjari, Mohammad Ali (Supervisor)
Abstract
Present study is to simulate laminar flow in a channel exposed to heat flux from the walls and filled with porous media by software ANSYS CFX in finite volume method. The analysis is based on the Naviere-Stokes equations in the flow field which are modified to Brinkman-Forchheimer equations to be applicable for porous media. Effect of Reynolds number and permeability on seepage velocity, temperature distribution, heat transfer and pressure drop are investigated.Simulations are performed for two cases: fully developed flow at the entrance of the porous media and developing flow, which are corresponding to the Reynolds numbers of Re=77.6 and Re=1553 respectively (U= 0.01 m/s and U= 0.2 m/s)....
Polyethylene glycol-coated porous magnetic nanoparticles for targeted delivery of chemotherapeutics under magnetic hyperthermia condition
, Article International Journal of Hyperthermia ; 2018 ; 02656736 (ISSN) ; Hedayatnasab, Z ; Karimian, H ; Sarraf, M ; Yeong, C. H ; Madaah Hosseini, H. R ; Abu Kasim, N. H ; Wong, T. W ; Rahman, N. A ; Sharif University of Technology
Taylor and Francis Ltd
2018
Abstract
Purpose: Although magnetite nanoparticles (MNPs) are promising agents for hyperthermia therapy, insufficient drug encapsulation efficacies inhibit their application as nanocarriers in the targeted drug delivery systems. In this study, porous magnetite nanoparticles (PMNPs) were synthesized and coated with a thermosensitive polymeric shell to obtain a synergistic effect of hyperthermia and chemotherapy. Materials and methods: PMNPs were produced using cetyltrimethyl ammonium bromide template and then coated by a polyethylene glycol layer with molecular weight of 1500 Da (PEG1500) and phase transition temperature of 48 ± 2 °C to endow a thermosensitive behavior. The profile of drug release...
Physicomechanical Properties of Porous Materials by Spark Plasma Sintering
, Article Critical Reviews in Solid State and Materials Sciences ; Volume 45, Issue 1 , 2020 , Pages 22-65 ; Azarniya, A ; Safavi, M. S ; Farshbaf Ahmadipour, M ; Esmaeeli Seraji, M ; Sovizi, S ; Saqaei, M ; Yamanoglu, R ; Soltaninejad, M ; Madaah Hosseini, H. R ; Ramakrishna, S ; Kawasaki, A ; Adams, S ; Reddy, M. V ; Sharif University of Technology
Taylor and Francis Inc
2020
Abstract
Metallic or ceramic micro/nanoporous materials have attracted particular attention due to some interesting structural and functional properties. There exist a variety of methods for producing porous materials by which optimized features can be reached. Spark plasma sintering (SPS) is one of these new-emerging approaches. This technique is often combined with conventional technologies and produce a variety of porous structures with tailorable microstructure and physicomechanical properties. This review addresses SPS and obtainable porous materials with nanoscale and microscale microstructural features. The processing methods, microstructural phenomena, and physicomechanical properties of...
Improvement of fractional flow model for miscible displacement process: An experimental investigation in single fractured porous medium
, Article Journal of Porous Media ; Volume 16, Issue 3 , 2013 , Pages 255-266 ; 1091028X (ISSN) ; Shadizadeh, S. R ; Rashtchian, D ; Sharif University of Technology
2013
Abstract
Most of the reservoirs in Iran are heterogeneous fractured carbonate reservoirs. Heterogeneity causes an earlier breakthrough and an unstable front, which leads to a lower recovery. In this study, a series of experiments was conducted whereby the n-Heptane displaced n-Decane in glass micromodels having different fracture geometries. Experimental data from image analysis of miscible displacement processes are used to modify the fractional flow equations by a heterogeneity factor. It is shown that the heterogeneity factor in the modified equations can be expressed as a function of fracture length and orientation
Electrophoretic deposition of porous hydroxyapatite coatings using polytetrafluoroethylene particles as templates
, Article Materials Science and Engineering C ; Volume 27, Issue 5-8 SPEC. ISS , 2007 , Pages 1482-1486 ; 09284931 (ISSN) ; Afshar, A ; Chen, J ; Zhang, X ; Sharif University of Technology
2007
Abstract
The formation of macroporous bioactive hydroxyapatite(HA) coatings using polytetrafluoroethylene(PTFE) particles were studied. The porous HA coatings were prepared onto a pure titanium substrate by electrophoretic deposition(EPD) at 120 V for 1.5 min using ethanol suspensions mixture of HA (500 nm in size) and PTFE (1-3 μm in size) particles. Subsequently, the composite coatings obtained by EPD were heated at 900 °C for 60 min to disintegrate the organic PTFE particles and sinter the inorganic HA particles. The calcinations of the PTFE led to the formation of porosity in the HA coating. These results demonstrate a new method for creating porous HA coatings on titanium. © 2006 Elsevier B.V....
The effect of local thermal non-equilibrium on impulsive conduction in porous media
, Article International Journal of Heat and Mass Transfer ; Volume 50, Issue 15-16 , 2007 , Pages 3244-3249 ; 00179310 (ISSN) ; Noghrehabadi, A. R ; Rees, D. A. S ; Sharif University of Technology
2007
Abstract
We examine the effect of local thermal non-equilibrium on the evolution of the stagnant temperature field in a semi-infinite porous medium. When local thermal equilibrium pertains, the temperature field which is induced by a step change in the temperature of a plane boundary is given by the classical conduction solution involving the complementary error function. When thermal local equilibrium does not apply, then conduction takes place more rapidly in one phase than in the other, although local thermal equilibrium is always approached as time increases. This note examines the evolution of the temperature field in each phase in detail using numerical methods, and the numerical solutions are...
Bioactive layer formation on alkaline-acid treated titanium in simulated body fluid
, Article Materials and Design ; Volume 28, Issue 7 , 2007 , Pages 2154-2159 ; 02613069 (ISSN) ; Afshar, A ; Chen, J ; Zhang, X ; Sharif University of Technology
Elsevier Ltd
2007
Abstract
Porous surface on titanium induces apatite formation in simulated body fluid (SBF). This work shows alkaline, acid and polishing treatment, which lead to create apatite coating. Specimens were soaked in 5 M solution of NaOH, 85% HCl-6% HF-9% H3PO4 and 2% HF-4% HNO3-94% H2O. Also many samples were polished with sandpaper. Specimens treated under the above conditions were soaked in simulated body fluid (SBF) for 5 days. Apatite formed within 5 days. The evaluation of Ca/P ratio of samples were made by EDAX analysis to get information of the Ca/P ratio. The values obtained for the apatite were in the range of 1.55, which is near to the stoichiometric value of apatite, for the sample, which was...
Relative permeability estimation of porous media: Comparison of implicit and explicit approaches
, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) ; Rashtchian, D ; Kharrat, R ; Vossoughi, S ; Khodabakhsh, M ; Taheri, S ; Sharif University of Technology
2006
Abstract
Relative permeability is used to describe quantitatively simultaneous transport of two or more immiscible phases through a porous medium. Accurate estimates of relative permeability curves depend on the method of estimation and are desired to obtain reliable predictions of flow behavior. To compare the accuracy of relative permeability estimation of implicit and explicit methods, primary drainage experiments of water by a sample oil fluid have been studied. The experiments performed on a horizontal glass type micromodel as a model of porous media sample under different fixed high flow rates condition to negate capillary pressure effects. The relative permeability of oil and water phases is...
Similarity solution of free convection in a stratified porous medium with variable permeability
, Article 2005 ASME Summer Heat Transfer Conference, HT 2005, San Francisco, CA, 17 July 2005 through 22 July 2005 ; Volume 4 , 2005 , Pages 485-491 ; 0791847314 (ISBN); 9780791847312 (ISBN) ; Khodabakhsh, M ; Saidi, M. H ; Sharif University of Technology
2005
Abstract
In this paper, similarity solution of free convection from inclined permeable wall embedded in a stratified porous medium is investigated. It is assumed that the heated wall has constant temperature and permeability along the wall is variable. Energy equation and Darcy's law as momentum have been used. Due to similarity solution we consider only large wall inclination angle. Effects of mass flux, permeability variation function, and wall inclination angle on thermal and velocity boundary layer thickness and heat transfer at the wall are investigated. Copyright © 2005 by ASME
Europium-doped yttrium silicate nanoparticles embedded in a porous SiO 2 matrix
, Article Nanotechnology ; Volume 15, Issue 11 , 2004 , Pages 1549-1553 ; 09574484 (ISSN) ; Lerondel, G ; Makino, H ; Yao, T ; Sharif University of Technology
2004
Abstract
Europium-doped yttrium silicate nanoparticles were grown inside a porous silicon oxide matrix by chemical impregnation of porous silicon layers, followed by heat treatments. The average size of the nanoparticles is 50 nm and they are dispersed almost uniformly within the whole porous layer. Local composition measurements demonstrate that Y and Eu are found only in nanoparticles, indicating a good phase separation efficiency. There is indirect evidence that yttrium silicate nanoparticles are nucleated around Eu ions. The crystalline phase of the particles is pure α-Y2Si2O7, with no trace of Y2O3 or Y2SiO5 or other Y2Si2O7 polymorphs. Structural purity is an advantage for this method, as in...
Spectral method for solving differential equation of gas flow through a micro-nano porous media
, Article Journal of Computational and Theoretical Nanoscience ; Volume 7, Issue 3 , 2010 , Pages 542-546 ; 15461955 (ISSN) ; Parand, K ; Shams, A ; Sofloo, H. G ; Sharif University of Technology
2010
Abstract
In this paper we propose, Spectral method to solve unsteady gas equation which is a nonlinear ordinary differential equation on semi-infinite interval. These approaches are based on Modified generalized Laguerre functions. These methods reduces the solution of this problem to the solution of systems of algebraic equations. We also compare this works with some other numerical results
Interdiffusion versus crystallization at semicrystalline interfaces of sintered porous materials
, Article Polymer ; Volume 156 , 2018 , Pages 54-65 ; 00323861 (ISSN) ; Pircheraghi, G ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Sintering process at temperature intervals close to the melting point of polymers is greatly important due to its role in synthesizing porous materials. During sintering, particles of polymeric materials coalesce throughout a process called interdiffusion. On the contrary, crystallization strongly affects the interdiffusion process at temperature intervals below and close to the melting point. Apparently, the outcome of the contention between these two factors would determine the interfacial width. Therefore, the current study presents a model, which takes both crystallization and interdiffusion into account, to predict sintering kinetic. Consequently, interfacial strength was assessed with...
Random walk simulation of miscible flow through heterogeneous 2D porous media considering dispersion tensor
, Article Chemical Engineering Science ; Volume 132 , August , 2015 , Pages 81-92 ; 00092509 (ISSN) ; Ghazanfari, M. H ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
Most of numerical approaches describing the behavior of miscible displacement in porous media through the solution of advection-dispersion equation suffer from numerical dispersion. Random Walk (RW) method is a good candidate to overcome this problem especially in heterogeneous media. In addition, how treating dispersion coefficient as a tensor might affect the accuracy of RW simulation results is not well understood. Here, a RW model was developed and used for simulating miscible displacement experiments performed on heterogeneous micromodels including single fracture/flow barrier. Dispersion coefficient was treated as a tensor and a hybrid scheme was used for velocity interpolation. The...
Improvement of buckley-leverett and fractional flow models for heterogeneous porous media
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Volume 37, Issue 10 , 2015 , Pages 1125-1132 ; 15567036 (ISSN) ; Shadizadeh, S. R ; Rashtchian, D ; Sharif University of Technology
Abstract
Most of the reservoirs in Iran and also around the world are in the middle of their production life and have passed their natural production period. Therefore, they should be a candidate for immiscible injection, e.g., water injection for secondary recovery, and/or miscible injection, like solvent injection for tertiary recovery. Also, it should be pointed out that most of the Iranian reservoirs are carbonate reservoirs. This type of reservoir is fractured and heterogenic. Heterogeneity causes an earlier breakthrough and immiscible injection causes an unstable front, which leads to a lower recovery. This article presents the modified equation of Buckley-Leverett and fractional flow...
Salt- and pH-resisting collagen-based highly porous hydrogel
, Article Polymer Journal ; Volume 40, Issue 2 , 2008 , Pages 94-103 ; 00323896 (ISSN) ; Kurdtabar, M ; Ghasemzadeh, H ; Sharif University of Technology
2008
Abstract
A novel approach was developed to prepare a highly porous hydrogel with superior salt- and pH-resisting properties. According to this method, synthetic comonomers, i.e. acrylic acid (AA) and 2-acrylamido-2-methylpropanesulfonic acid (AMPS), were polymerized and crosslinked in the presence of hydrolyzed collagen as a natural backbone. The characterizations of hydrogels were investigated by swelling experiment, Fourier transform infrared (FT-IR) spectroscopy, acid-base titration and thermogravimetric analysis (TGA). Morphology of the samples was examined by scanning electron microscopy (SEM). Experimental results indicate that the hydrogel has an absorbency of 360 and 73-82 g/g for distilled...
Entropy generation analysis of thermally developing forced convection in fluid-saturated porous medium
, Article Applied Mathematics and Mechanics (English Edition) ; Volume 29, Issue 2 , 2008 , Pages 229-237 ; 02534827 (ISSN) ; Ejlali, A ; Hooman, F ; Sharif University of Technology
2008
Abstract
Entropy generation for thermally developing forced convection in a porous medium bounded by two isothermal parallel plates is investigated analytically on the basis of the Darcy flow model where the viscous dissipation effects had also been taken into account. A parametric study showed that decreasing the group parameter and the Péclet number increases the entropy generation while for the Brinkman number the converse is true. Heatline visualization technique is applied with an emphasis on the Br < 0 case where there is somewhere that heat transfer changes direction at some streamwise location to the wall instead of its original direction, i.e., from the wall. © 2008 Editorial Committee of...
Hydrogen electrosorption on TiHg alloy in acidic solution
, Article Journal of Alloys and Compounds ; Volume 432, Issue 1-2 , 2007 , Pages 74-80 ; 09258388 (ISSN) ; Azizi, O ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
2007
Abstract
Hydrogen evolution and electrosorption on/in TiHg alloy have been investigated in acidic solution using cyclic voltammetry, open circuit potential transient, steady-state polarization, chronopotentiometry and electrochemical impedance measurements. Comparison has been made with pure Ti. Cyclic voltammetry and open circuit potential measurements show that hydrogen absorption into the electrode material occurs during proton discharge. The steady-state polarization curves in the course of positive and negative potential scans illustrate that the formation of absorbed hydrogen slightly improves the electrocatalytic properties of the electrode. The hydrogen diffusion coefficient into the bulk of...
Porosity and permeability effects on centerline temperature distributions, peak flame temperature, flame structure, and preheating mechanism for combustion in porous media
, Article Journal of Energy Resources Technology, Transactions of the ASME ; Volume 129, Issue 1 , 2007 , Pages 54-65 ; 01950738 (ISSN) ; Safavisohi, B ; Sharbati, E ; Sharif University of Technology
2007
Abstract
The applicability and usefulness of combustion in porous media is of much interest due to its competitive combustion efficiency and lower pollutants formation. In the previous works, the focus has been on the effects of combustion and heat transfer parameters such as excess air ratio, thermal power, solid conductivity, convective heat transfer coefficient, and radiation properties on centerline temperature and pollutant formations. A premixed combustion scheme and a fixed porous medium with constant geometrical parameters have been used in these works; therefore, the effects of porous material parameters have been less considered. In this research, the effects of geometrical parameters of...
Capillary pressure estimation of porous media using statistical pore size function
, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) ; Rashtchian, D ; Kharrat, R ; Vossoughi, S ; Khodabakhsh, M ; Taheri, S ; Sharif University of Technology
2006
Abstract
Real porous media even though seemingly homogenous and isotropic are most often nonuniform, and the nonuniformity may affect the macroscopic properties of porous media such as permeability, capillary pressure which is a result of the tortuous and circuitous nature of the flow paths in medium. In this study a glass type micromodel is considered as a porous media sample. A four parametric probability density function are used to express pore throat size, pore body size and pores length distributions which are measured using image analysis technique of porous model. The statistical models parameters are calculated by fitting the statistical model to the measured data of pore throat pore body...
Blue- and red-emitting phosphor nanoparticles embedded in a porous matrix
, Article Thin Solid Films ; Volume 503, Issue 1-2 , 2006 , Pages 190-195 ; 00406090 (ISSN) ; Lerondel, G ; Makino, H ; Yao, T ; Sharif University of Technology
2006
Abstract
Eu3+- and Ce3+-doped yttrium silicate, as well as Eu2+-doped zinc silicate nanoparticles, were grown in a porous SiO2 matrix using an impregnation method. For Y2Si 2O7:Eu3+, particles of about 50 nm size were obtained that exhibited several photoluminescence (PL) peaks in red. Different peaks showed slightly different decay times; however, their excitation mechanism was found the same. Increasing the Eu concentration increased the PL intensity while reducing the decay time. Y2Si2O7:Ce 3+ nanoparticles in the porous matrix showed bright blue emission, consisting of two peaks at 358 nm and 378 nm. Re-impregnation process was found effective in changing the relative intensity of the two peaks....