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    Experimental investigation of matrix wettability effects on water imbibition in fractured artificial porous media

    , Article Journal of Petroleum Science and Engineering ; Volume 86-87 , 2012 , Pages 165-171 ; 09204105 (ISSN) Rezaveisi, M ; Ayatollahi, S ; Rostami, B ; Sharif University of Technology
    2012
    Abstract
    Spontaneous water imbibition into the matrix blocks is known as the main mechanism for increased oil recovery from naturally fractured oil reservoirs. The rate of oil recovery and its ultimate value is mostly affected by wettability of the rocks and their pore structure. Oil viscosity also greatly influences the rate of oil recovery. A novel experimental model was utilized to study the imbibition mechanism under different wettability conditions. Matrix blocks made from different grain types and size distributions of glass beads were saturated with two different types of synthetic oil, to mimic the oil-saturated matrixes. The wetting characteristic of the models used in this study were... 

    Thermodynamic modeling of hydrogen sulfide solubility in ionic liquids using modified SAFT-VR and PC-SAFT equations of state

    , Article Fluid Phase Equilibria ; Volume 309, Issue 2 , 2011 , Pages 179-189 ; 03783812 (ISSN) Rahmati Rostami, M ; Behzadi, B ; Ghotbi, C ; Sharif University of Technology
    2011
    Abstract
    Equations of state based on the statistical associating fluid theory for potentials of variable range (SAFT-VR) and the perturbed chain statistical associating fluid theory (PC-SAFT) have been used to model the PVT behavior of ionic liquids and the solubility of H2S in six imidazolium-based ionic liquids. The studied systems included [bmim][PF6], [hmim][PF6], [bmim][BF4], [hmim][BF4], [bmim][NTF2] and [hmim][NTF2] at various temperatures and pressures.For pure components, parameters of the models have been obtained by fitting the models to experimental data on liquid densities; the average relative deviation between the calculated and experimental densities for ionic liquids is less than... 

    Thermal performance analysis of an energy pile with triple helix ground heat exchanger

    , Article Geothermics ; Volume 104 , 2022 ; 03756505 (ISSN) Farajollahi, A. H ; Asgari, B ; Rostami, M ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    A Ground Source Heat Pump (GSHP) is a renewable energy-based HVAC system that extracts or supplies heat from/to the ground via a Ground Heat Exchanger (GHE). One of the most commonly used types of GHE in GSHP systems is the energy pile. In this realm, the GSHP system with a triple helix energy pile has become the focus of attention. To this aim, a comprehensive three-dimensional transient Computational Fluid Dynamics model of the energy pile with triple helix GHE and the surrounding soil is developed. The effect of several parameters, including helix pitch, helix diameter and pipe diameter, on the thermal performance of the system, is investigated. Simulated cases are chosen using the design... 

    Modeling of wormhole propagation in carbonate rocks by use of in-situ-gelled acids

    , Article SPE Journal ; Volume 22, Issue 6 , 2017 , Pages 2032-2048 ; 1086055X (ISSN) Hosseinzadeh, B ; Bazargan, M ; Rostami, B ; Ayatollahi, S ; Sharif University of Technology
    2017
    Abstract
    Diversion in heterogeneous carbonate reservoirs plays the most important role to the success of acidizing. Without the use of diversion, more acid preferentially flows into the high-permeability region and leaves the low-permeability region underreacted. But a clear understanding of diverting agents, such as polymer-based in-situ-gelled acids, can help uniformly stimulate the near-wellbore region. In this paper, we correct the rheological model that was developed by Ratnakar et al. (2013) according to experimental data from Gomaa and Nasr-El-Din (2010b) by considering shear-rate effect in a two-scale continuum model. It is found that the rheology parameters and shear rate are influential... 

    Related-key impossible differential cryptanalysis of full-round HIGHT

    , Article ICETE 2013 - 10th International Joint Conference on E-Business and Telecommunications; SECRYPT 2013 - 10th International Conference on Security and Cryptography, Proceedings, Reykjavik ; 2013 , Pages: 537-542 ; 9789898565730 (ISBN) Rostami, S ; Chafjiri, S. B ; Tabatabaei, S. A. H ; Sharif University of Technology
    2013
    Abstract
    The HIGHT algorithm is a 64-bit block cipher with 128-bit key length, at CHES'06 as a lightweight cryptographic algorithm. In this paper, a new related-key impossible differential attack on the full-round algorithm is introduced. Our cryptanalysis requires time complexity of 2127.276 HIGHT evaluations which is slightly faster than exhaustive search attack. This is the first related-key impossible differential cryptanalysis on the full-round HIGHT block cipher. Copyright  

    Effect of gas impurity on the convective dissolution of CO2 in porous media

    , Article Energy ; Volume 199 , May , 2020 Mahmoodpour, S ; Amooie, M. A ; Rostami, B ; Bahrami, F ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Growing needs for energy and the essential role of fossil fuels in energy market require attempts such as carbon dioxide (CO2) sequestration in saline aquifers to stabilize and mitigate atmospheric carbon concentrations. The possibility of co-injection of impurities along with CO2 allows for the direct disposal of flue gas and hence a significant reduction in the cost of CO2 sequestration projects by eliminating the separation process. In this study, the results of series of novel experiments in a high-pressure visual porous cell are reported, which allow for visually and quantitatively examining the dynamics of convective dissolution in brine-saturated porous media in the presence of an... 

    Experimental and modelling study of gravity drainage in a three-block system

    , Article Transport in Porous Media ; 2020 Erfani, H ; Karimi Malekabadi, A ; Ghazanfari, M. H ; Rostami, B ; Sharif University of Technology
    Springer Science and Business Media B.V  2020
    Abstract
    Gravity drainage is known as the controlling mechanism of oil recovery in naturally fractured reservoirs. The efficiency of this mechanism is controlled by block-to-block interactions through capillary continuity and/or reinfiltration processes. In this study, at first, several free-fall gravity drainage experiments were conducted on a well-designed three-block apparatus and the role of tilt angle, spacers’ permeability, wettability and effective contact area (representing a different status of the block-to-block interactions between matrix blocks) on the recovery efficiency were investigated. Then, an experimental-based numerical model of free-fall gravity drainage process was developed,... 

    Experimental and modelling study of gravity drainage in a three-block system

    , Article Transport in Porous Media ; Volume 136, Issue 2 , 2021 , Pages 471-494 ; 01693913 (ISSN) Erfani, H ; Karimi Malekabadi, A ; Ghazanfari, M. H ; Rostami, B ; Sharif University of Technology
    Springer Science and Business Media B.V  2021
    Abstract
    Gravity drainage is known as the controlling mechanism of oil recovery in naturally fractured reservoirs. The efficiency of this mechanism is controlled by block-to-block interactions through capillary continuity and/or reinfiltration processes. In this study, at first, several free-fall gravity drainage experiments were conducted on a well-designed three-block apparatus and the role of tilt angle, spacers’ permeability, wettability and effective contact area (representing a different status of the block-to-block interactions between matrix blocks) on the recovery efficiency were investigated. Then, an experimental-based numerical model of free-fall gravity drainage process was developed,... 

    A novel islanding detection scheme for synchronous distributed generation using rate of change of exciter voltage over reactive power at DG-side

    , Article 2017 Australasian Universities Power Engineering Conference, AUPEC 2017 ; Volume 2017-November , 5 February , 2018 , Pages 1-5 ; 9781538626474 (ISBN) Rostami, A ; Bagheri, M ; Naderi, S. B ; Negnevitsky, M ; Jalilian, A ; Blaabjerg, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Abstract
    Penetration of distributed generation (DG) in distribution networks is rapidly increasing. DGs' application enhances system's reliability and power quality. However, along their benefits, there are some issues. One of the most important issues of DGs' application is the islanding. This paper presents a novel passive islanding detection scheme for synchronous DG based. In the proposed scheme, rate of change of exciter voltage over rate of change of reactive power at the DG-side (dE/dQDG) is taken into account. In reality, the voltage and reactive power of load depend on the exciter of the synchronous generator. Therefore, due to lack of inertia, response of these parameters to small changes... 

    Novel approaches in cancer management with circulating tumor cell clusters

    , Article Journal of Science: Advanced Materials and Devices ; Volume 4, Issue 1 , 2019 , Pages 1-18 ; 24682284 (ISSN) Rostami, P ; Kashaninejad, N ; Moshksayan, K ; Saidi, M. S ; Firoozabadi, B ; Nguyen, N. T ; Sharif University of Technology
    Elsevier B.V  2019
    Abstract
    Tumor metastasis is responsible for the vast majority of cancer-associated morbidities and mortalities. Recent studies have disclosed the higher metastatic potential of circulating tumor cell (CTC) clusters than single CTCs. Despite long-term study on metastasis, the characterizations of its most potent cellular drivers, i.e., CTC clusters have only recently been investigated. The analysis of CTC clusters offers new intuitions into the mechanism of tumor metastasis and can lead to the development of cancer diagnosis and prognosis, drug screening, detection of gene mutations, and anti-metastatic therapeutics. In recent years, considerable attention has been dedicated to the development of... 

    Efficient Search in Peer-to-Peer Networks

    , Ph.D. Dissertation Sharif University of Technology Rostami, Habib (Author) ; Habibi, Jafar (Supervisor)
    Abstract
    Peer-to-Peer networks are invented to enable participants (peers) to share their resources and find and use the shared resources of the others. So the main issue is the mechanism of finding granted resources of the other peers. In Peer-to-Peer networks, there is no central server to index shared resources of the peers. So peers should collaborate to provide a fully distributed mechanism for searching resources. Considering the huge size of peer-to-peer systems, it is apparent that efficiency of the search mechanism is very critical. In this thesis, to have efficient seach in Peer-to-Peer networks, we propose two approaches. Then based on these approaches, we propose the third approach to... 

    Investigation of Impurities and Structural Defects in Graphene

    , M.Sc. Thesis Sharif University of Technology Rostami, Melika (Author) ; Faez, Rahim (Supervisor)
    Abstract
    In this thesis the effects of impurities and different defects on electrical and magnetic properties of monolayer and bilayer graphene is investigated. Calculations are performed using density function theory. Alloying monolayer graphene with boron and nitrogen the energy gaps of 0.7 and 0.6 eV are obtained, respectively. Moreover, we show that BN is a good candidate for opening the band gap in graphene. Alloying monolayer graphene with BN the energy gap of 1.2 eV is obtained. Another way of opening band gap is to somehow break the symmetry between layers of the bilayer graphene. By alloying one layers of bilayer graphene with B, N or B-N, although the symmetry of layers is broken, each... 

    Undamped oscillations in fractional-order Duffing oscillator

    , Article Signal Processing ; February , 2014 , Pages 361–367 ; ISSN: 01651684 Rostami, M ; Haeri, M ; Sharif University of Technology
    2014
    Abstract
    This paper studies unamped oscillations of fractional-order Duffing system. Stability theorems for fractional order systems are used to determine the characteristic polynomial of the system in order to find the parametric ranges for undamped oscillations in this system. We also derive relations for estimating the frequency and the amplitude of the oscillations in this system using a describing function method. Finally numerical simulation results are provided to justify the analysis  

    Study of limit cycles and stability analysis of fractional arneodo oscillator

    , Article Journal of Optimization Theory and Applications ; Volume 156, Issue 1 , 2013 , Pages 68-78 ; 00223239 (ISSN) Rostami, M ; Haeri, M ; Sharif University of Technology
    2013
    Abstract
    This paper deals with the existence and the characteristics of the limit cycles in the fractional-order Arneodo system. The analysis is done using the describing function method. Our focus is on a special case where two limit cycles exist. The parametric range for the case of interest is derived, and the frequency and the amplitude of the oscillation are predicted. Numerical simulation results are presented to further demonstrate the reliability of the analysis  

    On the Characteristics of The Behavior of Multi-story Steel Frames Accompanied by Steel Shear Walls with Openings

    , M.Sc. Thesis Sharif University of Technology Rostami, Parisa (Author) ; Mofid, Massoud (Supervisor)
    Abstract
    As steel shear walls are usually applied in the central cores of buildings (around the elevators and stairs), the use of opening as door is inevitable in steel shear wall spans. On the other hand, because of weakening the performance of steel shear walls due to the presence of these openings, it is necessary to apply stiffeners around it. The use of stiffeners around all sides of opening continued to beams and columns, is very expensive. Therefore, the necessity of studying on the effect of different arrangements of stiffeners on the behavior of steel shear walls is felt. In this research, a number of steel shear walls with different characteristics in terms of plate aspect ratio, location... 

    Techno-Economical Analysis and Modeling of Carbon Capturing from Flue Gas by Adsorption

    , M.Sc. Thesis Sharif University of Technology Rostami, Fatemeh (Author) ; Avami, Akram (Supervisor)
    Abstract
    Population growth require increasing demand of Energy. The fossil fuels are the main source of energy. However, they are main source of carbon dioxide emissions. Considerable amount of fossil fuels is used in the power plants. Increasing trend of electricity consumption as well as the lack of alternative fuels such as renewables in the short time will increase the consumption of fossil fuels and emissions. The most important greenhouse gas emitted from the power plants is carbon dioxide. That's why the separation of carbon dioxide from the gas stream of power plants is necessary.Separation of the carbon dioxide by adsorption is considered in this project both experimentally and... 

    Undamped oscillations in fractional-order Duffing oscillator

    , Article Signal Processing ; Volume 107 , February , 2015 , Pages 361-367 ; 01651684 (ISSN) Rostami, M ; Haeri, M ; Sharif University of Technology
    Elsevier  2015
    Abstract
    This paper studies undamped oscillations of fractional-order Duffing system. Stability theorems for fractional order systems are used to determine the characteristic polynomial of the system in order to find the parametric ranges for undamped oscillations in this system. We also derive relations for estimating the frequency and the amplitude of the oscillations in this system using a describing function method. Finally numerical simulation results are provided to justify the analysis  

    Steel plate shear walls having door openings with different arrangements of stiffeners

    , Article Advances in Structural Engineering ; Volume 22, Issue 10 , 2019 , Pages 2222-2235 ; 13694332 (ISSN) Rostami, P ; Mofid, M ; Sharif University of Technology
    SAGE Publications Inc  2019
    Abstract
    As steel plate shear walls are typically used in the building central cores around the elevators and stairs, introduction of an opening as door seems to be inevitable in steel plate shear wall spans. Due to the weakening of the steel plate shear walls’ performance caused by this particular type of opening, the use of stiffeners around the opening is necessary. Nevertheless, introduction of stiffeners around all sides of the opening, which does continue to boundary elements, is very expensive and inefficient. Therefore, the study on the effect of different arrangements of stiffeners on the behavior of steel plate shear walls is significant. In this research, a number of steel plate shear... 

    A survey on exergy, energy and environmental analysis of sulfur recovery unit in case of five intensified configurations

    , Article Chemical Papers ; Volume 73, Issue 6 , 2019 , Pages 1529-1539 ; 03666352 (ISSN) Rostami, A ; Tavan, Y ; Sharif University of Technology
    Springer International Publishing  2019
    Abstract
    In this study, a combination of energy and exergy analysis is applied for the industrial sulfur recovery unit (SRU) in commercial simulation software. The data of energy and exergy are obtained from the simulator and Excel (for physical and chemical exergy), respectively. In doing so, five intensified SRU configurations namely: (1) hot gas bypass (2) acid gas bypass (3) inlet stream preheating (4) acid gas enrichment and (5) oxygen (air) enrichment are compared in terms of energy production, reaction furnace temperature, sulfur recovery and pollutant emission into environment. Then, irreversibility in these five arrangements is compared and all the proposed methods show higher useful exergy... 

    Topology awareness of overlay P2P networks

    , Article Concurrency and Computation: Practice and Experience ; Volume 19, Issue 7 , 2007 , Pages 999-1021 ; 15320626 (ISSN) Rostami, H ; Habibi, J ; Sharif University of Technology
    John Wiley and Sons Ltd  2007
    Abstract
    In overlay networks, the mechanism of a peer randomly joining and leaving a network, causes a topology mismatch between the overlay and the underlying physical topology. This causes a large volume of redundant traffic in the underlying physical network as well as an extra delay in message delivery in the overlay network. Topology mismatch occurs because overlay networks are not aware of their underlying physical networks. In this paper we present a mathematical model for topology awareness of overlay networks (degree of matching between an overlay and its underlying physical network) and the efficiency of message delivery on them. Then we experimentally show that the model is precise in the...