Search for: pore-size
Total 85 records
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
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...
Dead-end microfiltration of rough nonalcoholic beer by different polymeric membranes, Article Journal of the American Society of Brewing Chemists ; Volume 68, Issue 2 , 2010 , Pages 83-88 ; 03610470 (ISSN) ; Tabatabaei Nejad, S. A. R ; Soltanieh, M ; Tavakkoli, A ; Babaluo, A. A ; Fillaudeau, L ; Sharif University of Technology
Clarification of rough nonalcoholic beer using microfiltration as an alternative to conventional filtration with filter aids presents scientific and technical challenges for the brewing industry. An experimental pilot plant was used to evaluate the permeability and selectivity of polymeric membranes in the clarification process. Cellulose acetate (CA) with pore sizes of 0.2, 0.45, 0.8, and 1.2 μm, together with cellulose nitrate (CN), nylon (NY), and polytetrafluoroethylene (PTFE) with a pore size of 0.45 μm, were used at transmembrane pressures (TMP) of 1.0 and 2.0 bar. The data corroborated that the flux values of the CA, CN, and NY membranes were almost the same and reduced drastically,...
Transport Property Estimation of Non-Uniform Porous Media, Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 28, Issue 2 , 2009 , Pages 29-42 ; 10219986 (ISSN) ; Rashtchian, D ; Kharrat, R ; Vossoughi, S ; Sharif University of Technology
In this work a glass micromodel which its grains and pores are non-uniform in size shape and distribution is considered as porous medium. A two-dimensional random network modė, of micromodel with non-uniform pores has been constructed. The non-uniformity of porous model is achieved by assigning parametric distribution functions to pores throat and pores length, which was measured using image analysis technique. Statically derived expressions have been used for prediction of macroscopic properties of porous model including: dispersion coefficients, permeability-porosity ratio and capillary pressure. The results confirmed that predicted transport properties are in good agreement with the...
Capillary pressure estimation using statistical pore size functions, Article Chemical Engineering and Technology ; Volume 30, Issue 7 , 2007 , Pages 862-869 ; 09307516 (ISSN) ; Rashtchian, D ; Kharrat, R ; Vossoughi, S ; Sharif University of Technology
Capillary pressure curves, which have been employed for a long period of time by researchers interested in pore size distribution, are commonly obtained from experimental measurements. The dynamic capillary pressure that influences the flow is affected by many factors including the pore size characteristics and pore scale dynamics. Hence, it is important to investigate the variation of the estimated pore size distribution with capillary number. In this study, a glass type micromodel is considered as the porous media sample. A parametric probability density function is proposed to express the pore size distribution of the porous model, which is also measured using an image analysis technique....
Coke deposition mechanism on the pores of a commercial Pt-Re/γ- Al2O3 naphtha reforming catalyst, Article Fuel Processing Technology ; Volume 91, Issue 7 , 2010 , Pages 714-722 ; 03783820 (ISSN) ; Mohammadi, M ; Ghorbanpour, A ; Sharif University of Technology
Coke deposition mechanism on a commercial Pt-Re/γ-Al 2O3 naphtha reforming catalyst was studied. A used catalyst that was in industrial reforming operation for 28 months, as well as the fresh catalyst of the unit were characterized using XRD, XRF, and nitrogen adsorption/desorption analyses. Carbon and sulfur contents of the fresh and the used catalysts were determined using Leco combustion analyzer. The pore size distributions (PSD) of the fresh and the used reforming catalysts were determined using BJH and Comparison Plot methods. The Comparison Plot method produced the most reasonable PSDs for the catalysts. Through comparison of the PSDs of the fresh and the used catalysts, it was...
Ion transport through graphene oxide fibers as promising candidate for bblue energy harvesting, Article Carbon ; Volume 165 , 2020 , Pages 267-274 ; Esfandiar, A ; Sharif University of Technology
Elsevier Ltd 2020
Nanostructured graphene based membranes demonstrated excellent capabilities in various applications in nanofiltration and energy conversion due to unique atomically smooth surfaces and adjustable pore size or interlayers spacing at Angstrom scales. There are some reports on the osmotic power generation using physical confinements and electrostatic interactions between ions and GO membranes. However, the results indicated insufficient power densities (˂1 W/m2) can be achieved because of swelling of interlayer spacing of the GO membranes upon exposure to aqueous solutions which results in reducing the influence of confinement on ionic motilities. Here, the GO fibers is presented as one...
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
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...
Highly porous TiO2 nanofibres with a fractal structure, Article Nanotechnology ; Volume 17, Issue 2 , 2006 , Pages 520-525 ; 09574484 (ISSN) ; Taghavinia, N ; Iraji Zad, A ; Mahdavi, S. M ; Chavoshi, M ; Ahmadian, S ; Sharif University of Technology
TiO2 nanofibres were prepared using a templating method with tetraisopropylorthotitanate (TiPT) as a precursor. The preparation comprises liquid phase deposition on cellulose fibres followed by thermal removal of the cellulose template. The obtained TiO2 fibrous substance consists of micron-size fibres with a microstructure of nanofibres. It was demonstrated that nanofibres are basically formed through the aggregation of TiO2 nanoparticles and nanorods into chain structures during the thermal treatment process. The measured surface area of the TiO2 fibres was about 250 m2 g-1. It was shown that the pore size distribution is multi-scale and a fractal morphology was demonstrated with two...
Synthesis of Cationic Mesoporous Silica Nanoparticles as a Carrier for the Deliveryof Nucleic Acids, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Manouchehr ; Arpanaei, Ayyoob ; Javadi, Hamid Reza
Mesoporous silica nanoparticles (MSNP) have attracted lots of attentions because of their particular characteristics. Physical characteristics such as structure, morphology, porosity, and size of these nanoparticles have strong impact on their function and it can be conceived a wide range of applications for them by manipulating these characteristics. In this research, monodispersed MSNPs with a controllable size in the range of 50-130 nm and pore size in the range of 4-24 nm were synthesized and positively functionalized in order to develop a carrier for the delivery of nucleic acids (siRNA and pDNA). The MSNPs were synthesized by the template removing method.In this method, sodium...
Modeling and comparison of different simulations for release of amoxicillin from chitosan hydrogels, Article Polymer - Plastics Technology and Engineering ; Volume 52, Issue 11 , 2013 , Pages 1147-1153 ; 03602559 (ISSN) ; Ramazani S. A., A ; Shafiee, M ; Alemzadeh, I ; Ebrahimi, H ; Sharif University of Technology
In this research work, different devices made of glutaraldehyde cross-linked chitosan hydrogels loaded by amoxicillin, have been prepared using freeze-drying method. Effects of system parameters such as cross-linker concentration, pH, and gel structure on the morphology and release behavior of devices have been investigated using standard methods. Morphological studies were performed using SEM instrument and controlled releases are followed via spectrophotometeric method. Reaction of glutaraldehyde with chitosan has been studied using FTIR instrument. SEM micrographs have shown that with increasing cross-linker percentage in hydrogel, pore sizes increased where pore size distribution...
Theoretical and Experimental Study on the Adsorption and Desorption of Methane by Granular Activated Carbon at 25°C, Article Journal of Natural Gas Chemistry ; Volume 16, Issue 4 , December , 2007 , Pages 415-422 ; 10039953 (ISSN) ; Taghikhani, V ; Ghotbi, C ; Nemati Lay, E ; Shojaei, A ; Sharif University of Technology
A theoretical and experimental study was conducted to accurately determine the amount of adsorption and desorption of methane by various Granular Activated Carbon (GAC) under different physical conditions. To carry out the experiments, the volumetric method was used up to 500 psia at constant temperature of 25 °C. In these experiments, adsorption as well as desorption capacities of four different GAC in the adsorption of methane, the major constituent of natural gas, at various equilibrium pressures and a constant temperature were studied. Also, various adsorption isotherm models were used to model the experimental data collected from the experiments. The accuracy of the results obtained...
Simultaneous calculation of pore size distribution, capillary pressure, and relative permeability from injection-fall off-production test data, Article Special Topics and Reviews in Porous Media ; Vol. 5, issue. 1 , 2014 , p. 41-51 ; Jamshidi, S ; Salehi, S ; Sharif University of Technology
This work concerns simultaneous determination of relative permeability, capillary pressure, pore size distribution (PSD), and residual oil saturation data by optimization of well testing data, and introduces a new capillary pressure relationship, based on the Weibull distribution function, for direct determination of the PSD function from capillary pressure parameters. Three consecutive injection, fall off, and production well tests are performed on a predefined synthetic reservoir through simulation, and an optimization algorithm is used to find the parameters of relative permeability and capillary pressure curves as well as the value of residual oil saturation. The PSD function is also...
Dynamic modeling of the formation damage and mud cake deposition using filtration theories coupled with SEM image processing, Article Journal of Natural Gas Science and Engineering ; Volume 42 , 2017 , Pages 157-168 ; 18755100 (ISSN) ; Salehi, S ; Sharif University of Technology
Elsevier B.V 2017
In the present paper, a dynamic modeling is presented for deposition of the mud solid particles over and through the porous sandstones during permeability plugging experiments. Scanning electron microscopy (SEM) coupled with image processing are utilized to find the porosity and pore size distribution of the mud cake. The structure of the porous rock as well as the mud cake are modeled via bundle of the curved tubes approach and deposition probability of the solid particles has been taken into the account through filtration theories. Four different sandstones in addition to four mud samples were utilized to measure and predict the volume of the expelled fluid during the 30 min of filtration...
Nanorod carbon nitride as a carbo catalyst for selective oxidation of hydrogen sulfide to sulfur, Article Journal of Hazardous Materials ; Volume 364 , 2019 , Pages 218-226 ; 03043894 (ISSN) ; Eskandari, M. M ; Rashidi, A ; Baghalha, M ; Hassanisadi, M ; Hamzehlouyan, T ; Sharif University of Technology
Elsevier B.V 2019
Two-dimensional mesoporous carbon nitride and its highly efficient nanorod framework were prepared via hard-templating method. The obtained materials were fully characterized. The results showed that the samples structural ordering and morphology were similar to those of the parent silica templates; they had large pore volumes as well as high surface area structures. Carbon nitride carbocatalysts were used for H2S selective oxidation. The catalytic tests were carried out at 190, 210 and 230 °C in a fixed bed reactor. The obtained selectivity values for mesoporous carbon nitride rod and mesoporous carbon nitride toward elemental sulfur at 190 °C were 88.8% and 83%, respectively. Both samples...
Experimental Performance Analysis of Different Drill-in Fluids in Order to Reduce Formation Damage in Reservoir Sections, M.Sc. Thesis Sharif University of Technology ; Goodarznia, Iraj
Formation damage is defined as any process that reduses the reservoir permeability relative to its normal state. Two major causes of this problem are filtrate and solid invasion into the pore spaces of reservoir rock.Therefore, the drilling fluid used for drilling the reservoir sections should prevent such a problem as much as possible.The goal of this study is to optimize the weighting additive particle size distribution to prevent permeability damage in one of the southern Iranian oil fields. By analizing the capillary pressure data of core samples, it seems that fracture presence in rock matrix leads to poor quality of mudcake, resulting peremabilty reduction in near wellbore region....
Investigation of membrane preparation condition effect on the PSD and porosity of the membranes using a novel image processing technique, Article Journal of Applied Polymer Science ; Volume 131, Issue 4 , 15 February , 2014 ; ISSN: 00218995 ; Samimi, A ; Mousavi, S. A ; Bozarjamhari, R. B ; Sharif University of Technology
A totally computerized image processing program package is developed to analyze the SEM images of membrane surface and cross-section. Pore size distribution and porosity of the fabricated membranes are determined using the proposed image processing procedure. Furthermore, effect of coagulation bath temperature on the morphology and mechanical properties (such as tensile strength, strain break, tensile energy absorbent, and tensile stiffness) of Polysulfone (PSf) membranes are investigated. The results reveal that the mechanical properties are higher when N-methyl-2-pyrrolidone (NMP) is used as solvent. Also, an increase in the coagulation bath temperature caused a monotonous increase in the...
The relation between ink agglomerate size and pore size distribution of the cathode catalyst layer of PEM fuel cells and the effect of carbon corrosion on CCL structure, Article AIChE Annual Meeting, Conference Proceedings, 13 March 2011 through 17 March 2011, Chicago, IL ; 2011 ; 9780816910670 (ISBN) ; Eikerling, M ; Sharif University of Technology
Carbon corrosion is a major degradation mechanism in cathode catalyst layers (CCL) of polymer electrolyte membrane (PEM) fuel cells. Carbon corrosion (coupled with ionomer dissolution/degradation) induces severe changes in the CCL structure. In the present study, the inter-relation between the particle size of a packed sphere medium and the pore size distribution (PSD) is established. This relation is then used to predict the agglomerate size of the mix of Pt/C and ionomer in the catalyst ink, using experimentally measured PSD of the CCL. During cell degradation, the size of these agglomerates decreases; since, carbon corrosion causes carbon particles to decrease in size. Furthermore, as...
High flux electrospun nanofiberous membrane: Preparation by statistical approach, characterization, and microfiltration assessment, Article Journal of the Taiwan Institute of Chemical Engineers ; Volume 59 , 2016 , Pages 474-483 ; 18761070 (ISSN) ; Mousavi, S. A ; Bastani, D ; Sharif University of Technology
Taiwan Institute of Chemical Engineers
Preparation, characterization and evaluation of new generation of micro-filters based on polyacrylonitrile electrospun nanofiberous membrane (ENM) were thoroughly investigated. First, quantitative relationships between average diameter, bead area density of nano-fibers and certain electrospinning parameters, i.e., concentration, voltage, spinning distance, and feed rate, were established by empirical modeling based on a central composite design. The analysis revealed that concentration, voltage and distance are the significant parameters. Also, adequacy checking indicated the appropriateness of fit for the models. Afterwards, bead-free ENMs with diameter of 100-500 nm were prepared and...
Water retention and volumetric characteristics of intact and re-compacted loess, Article Canadian Geotechnical Journal ; Volume 53, Issue 8 , 2016 , Pages 1258-1269 ; 00083674 (ISSN) ; Sadeghi, H ; Belal Hossen, S. K ; Chiu, C. F ; Alonso, E. E ; Baghbanrezvan, S ; Sharif University of Technology
Canadian Science Publishing 2016
Alaboratory testing program was conducted to investigate the effects of microstructure on the water retention curve (WRC) and wetting-drying induced volume change in loess. The axis translation and vapor equilibrium techniques were adopted to control suction in the range of 0-400 kPa and 4-140 MPa, respectively. Hysteresis in the WRC of loess was observed for the entire range of suction studied. Compared to re-compacted loess, intact loess exhibits a more pronounced hysteresis in the suction range below 20 kPa, which can be explained by the ink-bottle pore neck effect or constricted pores. The hypothesis is supported by microstructural evidence of mercury intrusion porosimetry and scanning...
Preparation of biodegradable gelatin/PVA porous scaffolds for skin regeneration, Article Artificial Cells, Nanomedicine and Biotechnology ; 2016 , Pages 1-8 ; 21691401 (ISSN) ; Dadbin, S ; Frounchi, M ; Rajabi, S ; Sharif University of Technology
Taylor and Francis Ltd 2016
Porous scaffolds composed of gelatin/poly (vinyl alcohol), (Gel/PVA), were prepared using combination of freeze gelation and freeze drying methods. The effect of polymer concentration, gelatin/PVA ratio, and glutaraldehyde/gelatin ratio (GA/Gel) was investigated on morphology of pores, swelling ratio, biodegradation, and skin cell culture. At optimum preparation conditions the scaffolds had uniform pore size distributions showing high swelling ratio of 23.6. The scaffolds were of biodegradable nature and almost degraded in 28 days. Human dermal fibroblast cells (HDF) were cultured on the scaffolds and MTS assay was conducted to evaluate the influence of PVA on growth and proliferation of the...