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    Rheological and morphological behaviors of polyamide 6/acrylonitrile-butadiene-styrene/nanoclay nanocomposites

    , Article Journal of Thermoplastic Composite Materials ; Vol. 27, issue. 10 , 1 October , 2014 , pp. 1399-1416 ; ISSN: 08927057 Mojarrad, A ; Ramazani, S. A ; Ghasemi, I ; Vaziri, A ; Sharif University of Technology
    In this study, the effect of nanoclay on the rheological and morphological properties of polyamide 6 (PA6)/acrylonitrile-butadiene-styrene (ABS) blends was investigated. The scanning electron microscopy micrographs showed that with increment in the nanoclay content, the dispersed phase droplets size and their polydispersity index decreased, and the finer and more uniform dispersed phase was obtained. The transmission electron microscopy micrographs of nanocomposites indicated well-dispersed nanoclay tactoids in the polymer matrix produced by exfoliation of the nanoclay in the polymeric blends. Dynamic strain sweep experiments showed that the extent of the linear viscoelastic region is... 

    "Volume-preserving" conformational rheological models for multi-component miscible polymer blends using the GENERIC formalism

    , Article Macromolecular Theory and Simulations ; Volume 12, Issue 7 , 2003 , Pages 524-530 ; 10221344 (ISSN) Eslami, H ; Ramazani, A ; Khonakdar, H. A ; Sharif University of Technology
    A family of conformational rheological models for multi-component miscible polymer blends is developed using a modified form of the Poisson bracket formulation. Two conformation tensors called c1 and c2 are introduced to show the orientation of the first and the second components of a blend, respectively. The mobility tensor and the energy function for each blend component are expressed in terms of these conformation tensors. The interaction effects are also included by energy expressions. The predictions of this family of "volume-preserving" models are illustrated for a Hookean-type energy function and several expressions of the modified mobility tensors. The results are illustrated for... 

    Investigation of Oil-Asphaltene Slurry Rheological Behavior

    , Article Journal of Dispersion Science and Technology ; Vol. 35, issue. 8 , Aug , 2013 , p. 1155-1162 ; ISSN: 01932691 Tavakkoli, M ; Taghikhani, V ; Pishvaie, M. R ; Masihi, M ; Panuganti, S. R ; Chapman, W. G ; Sharif University of Technology
    The presence of asphaltene means additional difficulties related to transport and processing due to the increased crude oil viscosity caused by the asphaltene. For a better knowledge of the flow properties of asphaltene containing crude oils, it is necessary to understand how asphaltene affects the rheological properties. The aim of this article is to provide information on such rheological properties of oil-asphaltene slurry systems. The results of rheological experiments show that the non-Newtonian flow curves can be approximated by the Bingham plastic model to determine the apparent viscosity and the yield stress as a function of asphaltene concentration and temperature. An explanation is... 

    Mechanical performance of self-compacting concrete reinforced with steel fibers

    , Article Construction and Building Materials ; Volume 51 , 31 January , 2014 , Pages 179-186 ; ISSN: 09500618 Khaloo, A ; Raisi, E. M ; Hosseini, P ; Tahsiri, H ; Sharif University of Technology
    Self-compacting concrete (SCC) is a highly-workable concrete that without any vibration or impact and under its own weight fills the formwork, and it also passes easily through small spaces between rebars. In this paper, the effect of steel fibers on rheological properties, compressive strength, splitting tensile strength, flexural strength, and flexural toughness of SCC specimens, using four different steel fiber volume fractions (0.5%, 1%, 1.5%, and 2%), were investigated. Two mix designs with strengths of 40 MPa (medium strength) and 60 MPa (high strength) were considered. Rheological properties were determined through slump flow time and diameter, L-box, and V-funnel flow time tests.... 

    Morphological and mechanical properties of styrene butadiene rubber/nano copper nanocomposites

    , Article Results in Physics ; Volume 7 , 2017 , Pages 338-344 ; 22113797 (ISSN) Hadizadeh Harandi, M ; Alimoradi, F ; Rowshan, G ; Faghihi, M ; Keivani, M ; Abadyan, M ; Sharif University of Technology
    Elsevier B.V  2017
    In this research, rubber based nanocomposites with presence of nanoparticle has been studied. Styrene butadiene rubber (SBR)/nanocopper (NC) composites were prepared using two-roll mill method. Transmission electron microscope (TEM) and scanning electron microscope (SEM) images showed proper dispersion of NC in the SBR matrix without substantial agglomeration of nanoparticles. To evaluate the curing properties of nanocomposite samples, swelling and cure rheometric tests were conducted. Moreover, the rheological studies were carried out over a range of shear rates. The effect of NC particles was examined on the thermal behavior of the SBR using thermal gravimetric analysis (TGA). Furthermore,... 

    Insight into selection of appropriate formulation for colloidal gas aphron (CGA)-based drilling fluids

    , Article Petroleum Science ; Volume 17, Issue 3 , 2020 , Pages 759-767 Pasdar, M ; Kazemzadeh, E ; Kamari, E ; Ghazanfari, M. H ; Soleymani, M ; Sharif University of Technology
    China University of Petroleum Beijing  2020
    Application of light-weight drilling fluids is essential to develop depleted hydrocarbon reservoirs. Recently, colloidal gas aphron (CGA)-based fluids have been introduced for such applications due to their ability in controlling fluid losses. In this work, a comprehensive experimental study was performed to choose the best formulation for CGA fluids by implementing static stability tests, rheological behavior measurements, and bubble size analyses of CGAs. Xanthan gum polymer and sodium dodecyl benzene sulfonate (SDBS), an anionic surfactant, and cetyl trimethyl ammonium bromide (CTAB), a cationic surfactant, were utilized to prepare CGAs. For the range of experiments conducted, the... 

    Evaluation of rheological master curve models for bituminous binders

    , Article Materials and Structures/Materiaux et Constructions ; Volume 48, Issue 1-2 , January , 2015 , Pages 393-406 ; 13595997 (ISSN) Asgharzadeh, S. M ; Tabatabaee, N ; Naderi, K ; Partl, M. N ; Sharif University of Technology
    Kluwer Academic Publishers  2015
    Master curves of asphalt binders and mixtures have been traditionally used to evaluate their rheological behavior in the linear viscoelastic range. Different analytical models are available to describe the master curves of bituminous binders and mixtures. No models are currently considered universal for all modeling purposes. In this research, the general structure and capabilities of some of the most commonly used analytical models were investigated. Then, based on the patterns of phase angle master curves of ten neat and modified asphalt binders, four groups of master curve shapes were defined. The goodness of fit of the models for the different groups of master curves was used to develop... 

    Synthesis of a Series of PEG-Based ABA Triblock Copolymers and Their Influence on Rheology of Cement Slurries

    , Article Polymer - Plastics Technology and Engineering ; Volume 54, Issue 11 , 2015 , Pages 1113-1121 ; 03602559 (ISSN) Pourjavadi, A ; Doroudian, M ; Fakoorpoor, S. M ; Soleyman, R ; Sharif University of Technology
    Taylor and Francis Inc  2015
    A series of water-soluble ABA triblock copolymers consisting of a polyethylene glycol central block joined to two blocks of six different homopolymers have been synthesized via simple solvent-free and ecofriendly routes and characterized by FTIR and 1HNMR spectroscopy. Dispersing and slump-retaining abilities of the copolymers in cement slurries were evaluated by mini-slump spread method. Rheological measurements of samples with the best performance were carried out using a rate-controlled coaxial cylinder viscometer. The test results indicate that the dispersing power of the copolymers in cement pastes is strongly affected by the structure and degree of polymerization of the monomers  

    Effect ­­­­­of ultrasonic irradiation treatment on rheological behaviour of extra heavy crude oil: A solution method for transportation improvement

    , Article Canadian Journal of Chemical Engineering ; Volume 95, Issue 1 , 2017 , Pages 83-91 ; 00084034 (ISSN) Rahimi, M. A ; Ramazani S. A, A ; Alijani Alijanvand, H ; Ghazanfari, M. H ; Ghanavati, M ; Sharif University of Technology
    Wiley-Liss Inc  2017
    The highly viscous property of heavy oil often causes problems in its transportation in pipelines. Mixing heavy oil with light oil as well as ultrasound treatment are viable solutions to this problem. In this study, extra heavy crude oil samples were first diluted with 0, 0.05, 0.1, and 0.15 mL/mL (0, 5, 10, and 15 vol%) of a light crude oil; then the mixture was irradiated by ultrasonic waves for 0, 5, 10, 15, and 20 min; finally the viscous shear functions of all mixtures was measured at different values of shear rate at different temperature levels. The results revealed that the minimum viscosity of the diluted extra heavy crude oil samples was obtained at 10 min of ultrasonic... 

    Modeling of viscoelastic fluid flow behavior in the circular die using the leonov-like conformational rheological constitutive equations

    , Article Macromolecular Symposia ; Volume 274, Issue 1 , 2008 , Pages 6-10 ; 10221360 (ISSN) Ramazani, A ; Kanvisi, M ; Sharif University of Technology
    In this paper, the flow behavior of Leonov-Like conformational rheological model, which has root in the generalized Poisson bracket formalism based on the conformation tensor, have been studied in the circular die flow. Prediction of the normal stress differences during the flow of these fluids lets us to follow and calculate relaxation dependent phenomena such as die swell. The model predictions have been compared for the four families of mobility expressions. The Study of the model prediction sensitivity to its mobility term shows that model predictions can cover a wide range of rheological behaviors generally observed for polymer melts and solutions in the circular die flow. Copyright ©... 

    Enhanced oil-in-water droplet generation in a T-junction microchannel using water-based nanofluids with shear-thinning behavior: A numerical study

    , Article Physics of Fluids ; Volume 33, Issue 1 , 2021 ; 10706631 (ISSN) Besanjideh, M ; Shamloo, A ; Kazemzadeh Hannani, S ; Sharif University of Technology
    American Institute of Physics Inc  2021
    Nanofluids are widely used as the continuous phase during droplet formation in microsystems due to their impressive features such as excellent thermal, magnetic, and interfacial properties. Although it is well-known that nanofluids are susceptible to exhibit non-Newtonian behavior even at a low concentration of nanoparticles, effects of non-Newtonian behavior of nanofluids have not been studied on droplet formation thus far. In this study, oil-in-water droplet formation with a relatively high viscosity ratio of the immiscible phases was studied numerically in a T-junction microchannel. To inspect the non-Newtonian effects of aqueous nanofluids on droplet formation, empirical data on the... 

    Rheology of interfacial layers

    , Article Current Opinion in Colloid and Interface Science ; Vol. 19, issue. 6 , 2014 , pp. 514-519 ; ISSN: 13590294 Karbaschi, M ; Lotfi, M ; Kragel, J ; Javadi, A ; Bastani, D ; Miller, R ; Sharif University of Technology
    Dilational and shear viscoelasticities are important properties of interfacial layers. These quantities are particularly relevant in all systems which contain a huge internal interfacial area such as foams and emulsions. Therefore, also the 3D rheological behavior of foams or emulsions studied by respective methods is superimposed by the 2D interfacial rheology.We report on recent developments in dilational and shear rheology from an experimental point of view as well as discuss the state of the art of the underlying theories. Examples of most relevant experiments are also presented and discussed. Although not yet extensively investigated, the links between bulk rheology of foams and... 

    Comparison of Rheological Properties of Slurry with International Standards to Evaluate the Successfulness of Gachsaran Oil Field Cementation and Proposing Experimental Solutions

    , M.Sc. Thesis Sharif University of Technology Abbasi, Ali (Author) ; Ghotbi, Sirous (Supervisor) ; Moghadasi, Jamshid (Supervisor)
    The rheology of oil well cement (OWC) slurries is generally more complicated than that of conventional cement paste. In order to contend with bottom hole conditions, a number of additives are usually used in the OWC slurries. The objective of this research is to develop a fundamental understanding of the important mechanisms that affect the properties of OWC slurry such as rheological properties, free water, compressive strength and thickening time incorporating various chemical and mineral admixtures. The partial replacement of OWC using different nanoparticle weight percent has been proved to be a promising method. The mechanisms underlying the effects of chemical admixtures on the... 

    Rheological measurement of molecular weight distribution of polymers

    , Article e-Polymers ; Volume 13, Issue 1 , 2013 , Pages 217–228 ; 16187229 (ISSN) Khak, M ; Ahmad Ramazani, S.A ; Sharif University of Technology
    This paper has described a method to obtain the molecular weight distribution (MWD) of polymeric materials from their rheological data. The method has been developed for linear polymers with log normal molecular weight distribution. The rheological data required to obtain the molecular weight distribution are the shear storage modulus,G' (ω), and shear loss modulus,G' (ω) , extending from the terminal zone to the plateau region. For determining the molecular weight average, the method uses the relationship between stress moduli and relaxation spectrums, with the equation that connects dynamic rheological data with molecular weight distribution, and so it is not necessary to achieve the... 

    Numerical simulation of landslide impulsive waves by incompressible smoothed particle hydrodynamics

    , Article International Journal for Numerical Methods in Fluids ; Volume 56, Issue 2 , 2008 , Pages 209-232 ; 02712091 (ISSN) Ataie Ashtiani, B ; Shobeyri, G ; Sharif University of Technology
    An incompressible-smoothed particle hydrodynamics (I-SPH) formulation is presented to simulate impulsive waves generated by landslides. The governing equations, Navier-Stokes equations, are solved in a Lagrangian form using a two-step fractional method. Landslides in this paper are simulated by a submerged mass sliding along an inclined plane. During sliding, both rigid and deformable landslides mass are considered. The present numerical method is examined for a rigid wedge sliding into water along an inclined plane. In addition solitary wave generated by a heavy box falling inside water, known as Scott Russell wave generator, which is an example for simulating falling rock avalanche into... 

    Numerical modeling of die filling of semi-solid A356 aluminum alloy

    , Article Semi-Solid Processing of Alloys and Composites 10 - Selected, peer reviewed papers from the 10th International Conference on Semi-Solid Processing of Alloy and Composites, S2P 2008, Aachen, 16 September 2008 through 18 September 2008 ; Volume 141-143 , 2008 , Pages 605-610 ; 10120394 (ISSN); 9771012039401 (ISBN) Foroughi, A ; Aashuri, H ; Narimannezhad, A ; Khosravani, A ; Kiani, M ; Sharif University of Technology
    Trans Tech Publications Ltd  2008
    Computer base and simulation technique have been applied for modeling the semi-solid die filling and part of the solidification process of aluminum A356 alloy. A fairly simple one-phase rheological model has been implemented into a fluid flow finite element software Procast, to solve the partial differential equations. This model is purely viscous nature and is implemented in the power law cut-off model of Procast. The constitutive parameters of this model were determined for a rheocast A356 alloy. Using these parameters and comparing the simulation results with experimental data showed good correlation with the model prediction. The designed die for rheocasting was applied for the... 

    Idle time and gelation behavior in gelcasting process of PSZ in acrylamide system

    , Article Ceramic Transactions, 31 May 2009 through 5 June 2009 ; Volume 212 , JUL , 2010 , Pages 105-113 ; 10421122 (ISSN) ; 9780470876466 (ISBN) Sahraei Khanghah, N ; Faghihi Sani, M. A ; Sharif University of Technology
    Gelcasting is a novel forming method in fabricating complex three dimensional ceramic parts, and has many parameters and characteristics required to be specified. Up to now, few articles have been published on determination of the idle time of gelation precisely. In this work the chemorheology of gelation in aqueous solution of acrylamide and N, N′ methylenebisacrylamide monomer, and zirconia (PSZ) suspensions of this solution was investigated. As the viscosity of gel system increases abruptly in gelation point, idle time can be determined precisely by measurement of viscosity against time. Idle time can also be determined through temperature measurement against time since the reaction of... 

    Experimental investigation on effects of hybrid fibers on rheological, mechanical, and durability properties of high-strength SCC

    , Article Construction and Building Materials ; Volume 147 , 2017 , Pages 497-509 ; 09500618 (ISSN) Tabatabaeian, M ; Khaloo, A ; Joshaghani, A ; Hajibandeh, E ; Sharif University of Technology
    The aim of the present study is to investigate the effects of using hybrid fibers on rheological, mechanical and durability properties of the high-strength self-consolidating concrete (SCC). For this purpose, two types of fibers including hooked-end steel fibers and polypropylene fibers were used. In this study, a total of eleven mixtures were used: one as a control mix, one containing 0.5% steel fibers, four containing 0.5% hybrid fibers (steel and polypropylene), one containing 1.0% steel fibers and the four containing 1.0% hybrid fibers (steel and polypropylene). For investigating the rheological properties, slump flow, J-ring and V-funnel tests were performed. Mechanical properties were... 

    Development of a rheological model for polymeric fluids based on FENE model

    , Article Polyolefins Journal ; Volume 6, Issue 1 , 2019 , Pages 95-106 ; 23222212 (ISSN) Ebrahimi, H ; Ahmad Ramazani, S. A ; Davachi, S. M ; Sharif University of Technology
    Iran Polymer and Petrochemical Institute  2019
    Rheological models for polymer solutions and melts based on the finitely extensible non-linear elastic (FENE) dumbbell theory are reviewed in this study. The FENE-P model that is a well-known Peterlin approximation of the FENE model, indicates noticeable deviation from original FENE predictions and also experimental results, especially in the transient flow. In addition, both FENE and FENE-P models have some shortcomings from the point of view of theory. To overcome these shortcomings, a new approximation of the FENE spring force has been established. It has been used to develop a modified constitutive rheological model for polymeric fluids. In the procedure of modeling, the effect of... 

    Applications of highly salt and highly temperature resistance terpolymer of acrylamide/styrene/maleic anhydride monomers as a rheological modifier: Rheological and corrosion protection properties studies

    , Article Journal of Molecular Liquids ; Volume 294 , 2019 ; 01677322 (ISSN) Ghaderi, S ; Ramezani Saadat Abadi, A ; Haddadi, A ; Sharif University of Technology
    Elsevier B.V  2019
    Due to the weak performance of commercially affordable natural and synthetic polymeric thickeners in high temperatures and salinity, they fail to use in many applications especially in saline conditions with high temperatures. In this work, a new salt and temperature resistance acrylamide/styrene/maleic anhydride terpolymer (PASM-t) with self-associative properties was synthesized via a one-step inverse emulsion polymerization and its applicability as a rheological modifier and thickener was investigated. The characteristics of synthesized PASM-t (s-PASM-t) and its aqueous solutions were investigated using FT-IR, FE-SEM, GPC and rheometric mechanical spectrometry (RMS) analyses. The...