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in-situ
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In-Situ Synthesis of Zif-8 Nanocomposite Coating on Carbon Steel and Investigating the Effect of Adding Mbt on Corrosion Behavior and Sic Nanoparticles on Mechanical Properties
, M.Sc. Thesis Sharif University of Technology ; Abachi, Parvin (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
Nowadays, metal-organic frameworks have received a lot of attention due to their properties and characteristics such as controllable structure, high specific surface area and the tunable porosity size and have found many applications. One group of metal-organic frameworks are zeolitic imidazolate frameworks which ZIF-8 is a member of this family, and many studies have been conducted on it. In the present study, ZIF-8 nanocomposite coating was applied to the plain carbon steel substrate by synthesis at room temperature and immersion method, and its corrosion behavior and mechanical properties were investigated. The effect of Mercaptobenzothiazole (MBT) inhibitor on corrosion behavior and...
Effect of Heat Treatment on the Mechanical Properties of In-situ Al-Al3Ti Nanocomposite Fabricated by Mechanical Alloying and Hot Extrusion
, M.Sc. Thesis Sharif University of Technology ; Madaah Hosseini, Hamid Reza (Supervisor)
Abstract
In the present work, at first Al-20 wt% Ti nanocomposite was fabricated via mechanical alloying in high energy vibratiory mill for 1-4 hours. Particles morphology, crystallite size changes and phases transformation were investigated during mechanical alloying. Next, the powders which mechanically alloyed for 2 and 4 hours was compressed by hot extrusion at 500 ℃. The extruded specimens were investigated by different tests such as density, hardness, tensile and differential scanning calorimetry (DSC). Microscopic analysis and phases transformation were also investigated by optical microscopy (OM), field emission electron microscope (FESEM) and X-ray diffraction. Then, the samples were heat...
Transient thermo-poroelastic analysis of drilling-induced mechanical damage in nonfractured rocks
, Article Arabian Journal of Geosciences ; Volume 8, Issue 12 , 2015 , Pages 10803-10818 ; 18667511 (ISSN) ; Goodarznia, I ; Shadizadeh, S. R ; Sharif University of Technology
Springer Verlag
2015
Abstract
Permeability variations in reservoirs and around boreholes are of great interest in petroleum engineering due to the fact that they can significantly affect reserve estimates, reservoir development, well production or injection rate, and the likely success of remedial actions of near-wellbore damage. A fully coupled transient thermo-poroelastic concept with and without rock mechanical damage models is employed to evaluate stress distribution and permeability variation around the boreholes and breakouts. The anisotropy concept is applied to permeability, rock modulus, and uniaxial compressive strength using Weibull distribution. The Mogi–Coulomb failure criterion is employed to model breakout...
In situ horizontal stress from CPT in sand: a new approach
, Article International Journal of Geotechnical Engineering ; Volume 13, Issue 6 , 2019 , Pages 538-547 ; 19386362 (ISSN) ; Golestani Dariani, A. A ; Sharif University of Technology
Taylor and Francis Ltd
2019
Abstract
Despite the various approaches in the literature adopted for analysing cone penetration test (CPT), determination of the initial horizontal stress and relative density of a sandy soil during this test has not been tackled yet. In order to propose a new method in this regard, a numerical study of CPT has been performed and the predicted results have been compared with several databases of comprehensive calibration chamber tests. The penetration mechanism has been then fully investigated by presenting different kinds of outputs for the surrounding soil. Finally, an innovative procedure has been suggested for estimating the initial horizontal stress and relative density during performing CPT in...
In situ horizontal stress from CPT in sand: a new approach
, Article International Journal of Geotechnical Engineering ; Volume 13, Issue 6 , 2019 , Pages 538-547 ; 19386362 (ISSN) ; Golestani Dariani, A. A ; Sharif University of Technology
Taylor and Francis Ltd
2019
Abstract
Despite the various approaches in the literature adopted for analysing cone penetration test (CPT), determination of the initial horizontal stress and relative density of a sandy soil during this test has not been tackled yet. In order to propose a new method in this regard, a numerical study of CPT has been performed and the predicted results have been compared with several databases of comprehensive calibration chamber tests. The penetration mechanism has been then fully investigated by presenting different kinds of outputs for the surrounding soil. Finally, an innovative procedure has been suggested for estimating the initial horizontal stress and relative density during performing CPT in...
Numerical simulation of sanding using a coupled hydro-mechanical sand erosion model
, Article Journal of Rock Mechanics and Geotechnical Engineering ; Volume 12, Issue 4 , 2020 , Pages 811-820 ; Pak, A ; Sharif University of Technology
Chinese Academy of Sciences
2020
Abstract
Mechanical failure of materials adjacent to the production cavity and material disaggregation caused by fluid drag are considered as the most important parameters that affect sand production. In light of such factors, the coupling of two mechanisms-mechanical instability and hydrodynamic erosion-is indispensable in order to model this phenomenon successfully. This paper examines the applicability of a coupled hydro-mechanical erosion criterion for simulating sand production using the finite element method. The porous medium was considered fully saturated. The onset of sanding and production of sand were predicted by coupling mechanical failure and subsequent erosion of the grain particles...
Enhancing seebeck coefficient and electrical conductivity of polyaniline/carbon nanotube–coated thermoelectric fabric
, Article Journal of Industrial Textiles ; 2021 ; 15280837 (ISSN) ; Ramazani Saadatabadi, A ; Pourjahanbakhsh, M ; Siadati, M. H ; Sharif University of Technology
SAGE Publications Ltd
2021
Abstract
In this work, flexible thermoelectric fabrics, polyester/yarn fabrics coated with polyaniline/carbon nanotube (PANI/CNT) nanocomposite, were fabricated by sequential processing: (I) polyaniline/carbon nanotube nanocomposites preparation by a one-step in-situ polymerization and (II) dip coating of a mixture solution of CNT-doped PANI on a polyester/yarn fabric. Nanocomposites were synthesized with various CNT content (0.5, 2.5, 5, and 10 wt%) and characterized using different methods. The Seebeck coefficient and electrical conductivity measurements were used to determine their thermoelectric properties. The results revealed significant improvement in both electrical conductivity and the...
In situ growth of carbon nanotubes in alumina-zirconia nanocomposite matrix prepared by solution combustion method
, Article Ceramics International ; Volume 38, Issue 4 , May , 2012 , Pages 3273-3280 ; 02728842 (ISSN) ; Pilehvari, S ; Faghihi Sani, M. A ; Moradi, H ; Akbarnejad, M ; Sharif University of Technology
2012
Abstract
In this work successful synthesis of multiwall carbon nanotube (CNT) using solution combustion and chemical vapor deposition (CVD) methods are reported. Ceramic nanocomposite samples of (Al 2-xFe xO 3)-(y)ZrO 2 formula with x = 0.017, 0.034 and 0.17 and y = 0.15 were initially prepared. These were then subjected to CVD process during which the in situ reduction of iron oxide to metallic iron (Fe/Fe 3C) phase/s provided the necessary catalyst for the CNT formation. The formation of long flexible filaments with a smooth and regular surface bridging between alumina-zirconia (AZ) grains could be detected. The diameters of the formed filaments were in the range of ∼70 to ∼320 nm and length of the...
The operational and reservoir parameters influencing the performance of top-down in situ combustion in fractured reservoirs: 2D block-scale simulation of networked fractures
, Article Petroleum Science and Technology ; Volume 30, Issue 3 , 2011 , Pages 256-270 ; 10916466 (ISSN) ; Kharrat, R ; Vossoughi, S ; Sharif University of Technology
2011
Abstract
Top-down in situ combustion (ISC) involves the stable propagation of a combustion front from the top vertical injector to the bottom horizontal producer. With the exception of laboratory studies of conventional sandstones, no application of the process in fractured carbonates has been addressed. The aim of the present work is to study ISC in the presence of a system of networked fractures using a thermal reservoir simulator from the Computer Modeling Group (CMG; Calgary, AB, Canada). The performance of ISC is compared with nonfractured system under similar conditions. To obtain more realistic results, a history-matched and validated combustion model of an Iranian naturally fractured...
Toe-to-heel air injection: Investigation of the effect of fractures geometrical properties on process performance
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Volume 33, Issue 22 , Sep , 2011 , Pages 2067-2077 ; 15567036 (ISSN) ; Kharrat, R ; Ghotbi, C ; Sharif University of Technology
Abstract
Toe to heel air injection has been studied on non-fractured sandstone models and is found to be a promising enhanced oil recovery method for certain heavy oil reservoirs, such as those in Canada, but its applicability on fractured reservoirs, such as those in the Middle East, is not investigated yet. The objective of this article is to evaluate the effect of fractures geometrical parameters, such as fracture density, orientation, and location, on the performance of the process in laboratory scale. Simulation results showed that toe-to-heel air injection is more applicable on highly networked fractured reservoirs, such as those that occur in Persian Gulf coast compared to lower density...
The assessment of fracture geometrical properties on the performance of conventional in situ combustion
, Article Petroleum Science and Technology ; Volume 29, Issue 6 , Feb , 2011 , Pages 613-625 ; 10916466 (ISSN) ; Kharrat, R ; Ghotbi, C ; Sharif University of Technology
Abstract
The aim of the present work is to evaluate the effect of fractures geometrical properties such as orientation, density, location, and networking on the conventional fire flooding (CFF) process performance through simulation analysis. Combustion parameters of a fractured low-permeable carbonate heavy oil reservoir in Iran called Kuh-E-Mond (KEM); applied for simulation study and simulator has been validated with KEM combustion tube experimental data. The validated model was modified to study CFF in 3D semi-scaled combustion cells. Simulation results confirmed that CFF is more feasible in the case of densely fractured reservoirs such as those in the Middle East
In-situ aluminum matrix composite produced by friction stir processing using FE particles
, Article Materials Science and Engineering A ; Volume 641 , 2015 , Pages 380-390 ; 09215093 (ISSN) ; Samadi, S ; Janghorban, Z ; Movahedi, M ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
In-situ aluminum matrix composites were fabricated by 1-3 passes of friction stir process (FSP) using iron (Fe) particles with initial size of 10. μm. Although the initial reinforcing particles were relatively large in size and also agglomerated particles were formed in the obtained composites, all of the processed specimens fractured from the base metal during transverse tensile test. Longitudinal tensile tests revealed that the ultimate tensile strength (UTS) of the composites was up to 43% higher than that of the base metal; however, the strain to fracture of the composites reached to about 0.2. Al-Fe intermetallic compounds (IMCs) formed at the interface of the aluminum matrix and Fe...
In situ LIF temperature measurements in aqueous ammonium chloride solution during uni-directional solidification
, Article Experiments in Fluids ; Volume 48, Issue 4 , April , 2010 , Pages 651-662 ; 07234864 (ISSN) ; Lum, C. L ; Koochesfahani, M. M ; Sharif University of Technology
2010
Abstract
We present in situ whole-field measurements of the temperature field using laser-induced fluorescence in a study of bottom-chilled uni-directional solidification of aqueous ammonium chloride. We utilize a two-color, two-dye, ratiometric approach to address the significant spatial and temporal variations of laser sheet intensity field due to refractive index variations caused by the evolving concentration and temperature fields. In our work we take advantage of two temperature sensitive fluorescent dyes with opposite temperature sensitivities in order to increase the overall sensitivity and temperature resolution of the measurements. The resulting temperature sensitivity (about 4% K-1) is...
Impact of preparation method of TiO2-RGO nanocomposite photoanodes on the performance of dye-sensitized solar cells
, Article Electrochimica Acta ; Volume 219 , 2016 , Pages 38-48 ; 00134686 (ISSN) ; Mohammadi, M. R ; Lianos, P ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
In this work, a comparative study has been performed on two ex-situ and one in-situ doping of titania photoanodes with reduced graphene oxide. The presence of finely dispersed reduced graphene oxide facilitates electron transport and reduces electron-hole recombination resulting in a better performance of doped titania photoanodes. It was found that in-situ doping, i.e. introduction of graphene oxide in solution together with titania precursor was the most performant case of graphene doping. This result was obvious by studying dye-sensitized solar cells based on such doped photoanodes but was also and mainly analytically demonstrated by subjecting the obtained materials to characterization...
Liquefaction evaluation based on CPTu soil classification chart
, Article Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering: The Academia and Practice of Geotechnical Engineering, 5 October 2009 through 9 October 2009, Alexandria ; Volume 2 , 2009 , Pages 1028-1031 ; 9781607500315 (ISBN) ; Eslami, A ; Kangarani, M. R ; Sharif University of Technology
Abstract
Liquefaction is one of the most serious geotechnical hazards that may cause irreparable and financial damages. Based on in-situ testing results, several methods have been developed to evaluate the liquefaction potential. Due to continuous and repeated records, the piezocone (CPTu) has gained wide acceptance among other in-situ tests in geotechnical practice. In this paper, a new approach is proposed for liquefaction potential evaluation based on CPTu results. The new approach is verified by ten CPTu soundings (case histories) derived from different sites. By analyzing the liquefied sites, an area on the soil classification charts was introduced in this paper, showing the soil types which are...
Cone penetration test in sand: anumerical-analytical approach
, Article Computers and Geotechnics ; Volume 90 , 2017 , Pages 176-189 ; 0266352X (ISSN) ; Golestani Dariani, A. A ; Sharif University of Technology
Abstract
Separation of the effects of initial horizontal stress and relative density on cone tip resistance in sandy soils has been a complicated issue for many years. In order to overcome this problem, a numerical modeling of CPT which has been verified by calibration chamber tests, has been used in this paper to achieve a reliable analytical solution. The analytical solution has resulted in two relationships for sleeve friction and cone tip resistance in terms of the initial conditions of sandy soil. Based on the presented solution, the initial horizontal stress and relative density can be determined according to CPT measurements. © 2017 Elsevier Ltd
Microstructure, Strength, and Wear Behavior Relationship in Al-Fe3O4 Nanocomposite Produced by Multi-pass Friction Stir Processing
, Article Journal of Materials Engineering and Performance ; Volume 26, Issue 7 , 2017 , Pages 3516-3530 ; 10599495 (ISSN) ; Movahedi, M ; Kokabi, A. H ; Sharif University of Technology
Springer New York LLC
2017
Abstract
Aluminum matrix in situ nanocomposite was produced by one to six passes friction stir processing (FSP) with pre-placed Fe3O4 nanoparticles (15-20 nm). Microstructure studies showed that solid-state reactions between the aluminum matrix and Fe3O4 particles during the process led to in situ formation of Al3Fe and Al5Fe2 in the stir zone. Initial Fe3O4 as well as Al-Fe intermetallic compounds (IMCs) particles were homogeneously dispersed in a fine grain matrix after six passes of FSP. Hardness and ultimate tensile strength of the composites were increased 64 and 27%, respectively, compared to the base metal. The reasons were studied in the light of reinforcing particles distribution, formation...
A modified method for predicting the stresses around producing boreholes in an isotropic in-situ stress field
, Article International Journal of Rock Mechanics and Mining Sciences ; Volume 96 , 2017 , Pages 85-93 ; 13651609 (ISSN) ; Veyskarami, M ; Al Ajmi, A. M ; Masihi, M ; Sharif University of Technology
Abstract
Rock formations are always under in situ stresses due to overburden or tectonic stresses. Drilling a well will lead to stress redistribution around the well. Understanding such a stress redistribution, and adopting a proper failure criterion, play a vital role in predicting any potential wellbore failure. However, most of the published analytical models are based on assumptions that do not satisfy the boundary conditions during production, that is, when the well pressure is less than the pore pressure. This paper is aimed at the modeling of the stress regime around the wellbore through combining the poroelastic model with proper boundary conditions under different flow regimes. As a result,...
Evolution of microstructure and mechanical properties of Al-5 wt% Ti composite fabricated by P/M and hot extrusion: effect of heat treatment
, Article Materials Science and Engineering A ; Volume 689 , 2017 , Pages 166-175 ; 09215093 (ISSN) ; Madaah Hosseini, H. R ; Sharif University of Technology
Abstract
An Al-5 wt% Ti composite was fabricated via powder metallurgy and hot extrusion from initial pure Al and Ti powders. The effect of subsequent heat treatment at 600 °C for different time intervals on microstructure and mechanical properties was investigated. XRD and EDS analyses showed the in-situ formation of Al3Ti intermetallic. SEM micrographs demonstrated the formation of core-shell structured particles in Al matrix for composites heat treated up to moderate heating times (4 h). Generation of voids and pores in the heat treated composites was considered as a result of the Kirkendall effect. Mechanical properties of composites were studied by hardness and tensile testing methods at room...
In situ synthesized TiO2-polyurethane nanocomposite for bypass graft application: In vitro endothelialization and degradation
, Article Materials Science and Engineering C ; Volume 114 , May , 2020 ; Bagheri, R ; Pourjavadi, A ; Ghanbari, H ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
The in vitro endothelial response of human umbilical vein endothelial cells was investigated on a poly (caprolactone)-based polyurethane surface vs an in situ TiO2-polyurethane nanocomposite surface, which has been produced as scaffolds for artificial vascular graft. The in situ synthesis of TiO2 nanoparticles in polyurethane provided surface properties that facilitated cellular adhesion, cell sensing, cell probing and especially cell migration. Cells on the nanocomposite surface have elongated morphology and were able to produce more extracellular matrix. All of these advantages led to an increase in the rate of endothelialization of the nanocomposite scaffold surface vs pure polyurethane....