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    An experimental investigation of asphaltene precipitation during natural production of heavy and light oil reservoirs: The role of pressure and temperature

    , Article Petroleum Science and Technology ; Volume 29, Issue 10 , 2011 , Pages 1054-1065 ; 10916466 (ISSN) Alizadeh, A ; Nakhli, H ; Kharrat, R ; Ghazanfari, M. H ; Sharif University of Technology
    Many oil reservoirs encounter asphaltene precipitation as a major problem during natural production. In spite of numerous experimental studies, the effect of temperature on asphaltene precipitation during pressure depletion at reservoir conditions is still obscure in the literature. To study their asphaltene precipitation behavior at different temperatures, two Iranian light and heavy live oil samples were selected. First, different screening criteria were applied to evaluate asphaltene instability of the selected reservoirs using pressure, volume, and temperature data. Then, a high pressure, high temperature filtration (HPHT) setup was designed to investigate the asphaltene precipitation... 

    Experimental study of asphaltene precipitation behavior during miscible carbon dioxide injection

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 36, issue. 14 , July , 2014 , pp. 1523-1530 ; ISSN: 15567036 Alizadeh, A ; Nakhli, H ; Kharrat, R ; Ghazanfari, M. H ; Aghajani, M ; Sharif University of Technology
    Many reservoir and production engineers face asphaltene precipitation as a major problem during miscible carbon dioxide flooding projects. Experimental studies regarding asphaltene precipitation are therefore employed to assist in selecting appropriate facilities and proper operation schemes. During this study, a series of high pressure, high temperature experiments are designed and performed to analyze asphaltene precipitation behavior of an Iranian light reservoir crude at reservoir conditions due to natural production and miscible CO2 gas injection. For both sets of experiments, two different temperature levels (including reservoir temperature) are selected to investigate the role of... 

    Flow and heat transfer analysis of turbine blade cooling passages using network method

    , Article ASME 2012 Gas Turbine India Conference, GTINDIA 2012 ; 2012 , Pages 523-531 ; 9780791845165 (ISBN) Alizadeh, M ; Izadi, A ; Fathi, A ; Khaledi, H ; Sharif University of Technology
    Modern turbine blades are cooled by air flowing through internal cooling passages. Three-Dimensional numerical simulation of these blade cooling passages is too time-consuming because of their complex geometries. These geometrical complexities exist as a result of using various kinds of cooling technologies such as rib turbulators (inline, staggered, or inclined ribs), pin fin, 90 and 180 degree turns (both sharp and gradual turns, with and without turbulators), finned passage, by-pass flow and tip cap impingement. One possible solution to simulate such sophisticated passages is to use the one-dimensional network method, which is presented in the current work. Turbine blade cooling channels... 

    Density and temperature dependencies of liquid surface tension

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 30, Issue 2 , 2011 , Pages 79-90 ; 10219986 (ISSN) Alizadeh Osgouei, H ; Parsafar, G. A ; Akbarzadeh, H ; Sharif University of Technology
    In this paper the density and temperature dependencies of surface tension are investigated. Using the Lennard-Jones (12,6), as an effective pair interaction potential, a linear expression is derived for isotherms of γ /ρ 2 versus ρ 2 for some normal and ChloroFluoroCarbons (CFCs) fluids, where is surface tension and ρ = 1/v is molar density. The linearity behavior of the derived equation is well fitted onto the experimental data of surface tension for monatomic, diatomic, nonpolar, polar, hydrogen-bonded and chlorofluorocarbons. In addition, the temperature dependence of surface tension for 20 different fluids is examined, in which the contributions of both terms of the average effective... 

    Two-Step Physical Deposition of a Compact CuI Hole-Transport Layer and the Formation of an Interfacial Species in Perovskite Solar Cells

    , Article ChemSusChem ; 2016 , Pages 1929-1937 ; 18645631 (ISSN) Gharibzadeh, S ; Nejand, B. A ; Moshaii, A ; Mohammadian, N ; Alizadeh, A. H ; Mohammadpour, R ; Ahmadi, V ; Alizadeh, A ; Sharif University of Technology
    Wiley-VCH Verlag  2016
    A simple and practical approach is introduced for the deposition of CuI as an inexpensive inorganic hole-transport material (HTM) for the fabrication of low cost perovskite solar cells (PSCs) by gas–solid phase transformation of Cu to CuI. The method provides a uniform and well-controlled CuI layer with large grains and good compactness that prevents the direct connection between the contact electrodes. Solar cells prepared with CuI as the HTM with Au electrodes displays an exceptionally high short-circuit current density of 32 mA cm−2, owing to an interfacial species formed between the perovskite and the Cu resulting in a long wavelength contribution to the incident photon-to-electron... 

    Magnetic pH-responsive nanocarrier with long spacer length and high colloidal stability for controlled delivery of doxorubicin

    , Article Colloids and Surfaces B: Biointerfaces ; Vol. 116 , April , 2014 , pp. 49-54 ; ISSN: 09277765 Pourjavadi, A ; Hosseini, S. H ; Alizadeh, M ; Bennett, C ; Sharif University of Technology
    A novel magnetic nanocarrier with long spacer length and high colloidal stability has been prepared for effective delivery of doxorubicin (DOX). First, poly(amidoamine) (PAMAM) dendrimer was grown up onto the surface of superparamagnetic iron oxide nanoparticles to increase the loading amount of amine groups. Then, terminal amine groups were functionalized by polyethylene glycol dimethylester to increase the spacer length. Then anticancer drug DOX was covalently attached onto the system by hydrazone bond to forms a pH-sensitive nanocarrier. This system is designed to combine the advantage of magnetic targeting, high drug loading capacity, and controlled release  

    Experimental investigation of water alternating CH4-CO 2 mixture gas injection in light oil reservoirs

    , Article International Journal of Oil, Gas and Coal Technology ; Vol. 8, issue. 1 , 2014 , p. 31-40 Alizadeh, A ; Ghazanfari, M. H ; Taghikhani, V ; Badakhshan, A ; Sharif University of Technology
    This paper studies a WAG process for improving the recovery efficiency in light oil reservoirs. Until now, few references have reported the role of CO2 mole percent on recovery improvement in light oil reservoirs. The injected gas was changed, and the effect of composition changes on performance of core flood experiments were conducted at fixed flow rate. Five series of experiments (varied in methane mole percentages, 0, 25, 50, and 75, 100) were systematically examined. The results indicated that the oil recovery efficiency improved with the increasing of CO2 mole ratio and there was also maximum recovery efficiency in this work. That would be helpful to better understanding the role of CO2... 

    A comparison of WAG and SWAG processes: Laboratory and simulation studies

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Volume 35, Issue 23 , 2013 , Pages 2225-2232 ; 15567036 (ISSN) Heidari, P ; Kharrat, R ; Alizadeh, N ; Ghazanfari, M. H ; Sharif University of Technology
    The use of water-alternating-gas injection can potentially lead to improved oil recovery from the fields; simultaneous water and gas injection is a form of water-alternating-gas injection. However, there is still an incomplete understanding of these processes and the need for comparative work is inevitable. Core flood experiments and compositional simulations of water-alternating-gas and simultaneous water and gas processes are presented. Immiscible, near miscible, and miscible modes of injection are covered. Matching process is done and optimization of design parameters (injection rate, slug size, water-alternating-gas ratio, and injection gas) is performed. Experimental data demonstrate... 

    Investigation on cristobalite crystallization in silica-based ceramic cores for investment casting

    , Article Journal of the European Ceramic Society ; Volume 33, Issue 15-16 , 2013 , Pages 3397-3402 ; 09552219 (ISSN) Kazemi, A ; Faghihi Sani, M. A ; Alizadeh, H. R ; Sharif University of Technology
    In this work, cristobalite crystallization and its effects on mechanical and chemical behaviour of injection moulded silica-based ceramic cores were investigated. In order to simulate casting process condition, the sintered samples at 1220 °C were also heated up to 1430 °C. Flexural strength test was carried out on both sintered and heat treated samples. Chemical resistance of the cores was evaluated by leaching the samples inside 43. wt% KOH solution at its boiling point. Phase evolution and microstructure were investigated by thermal analyses (DTA and DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical microscopy (OM). Results showed that cristobalite was... 

    Welding metallurgy of stainless steels during resistance spot welding part II –heat affected zone and mechanical performance

    , Article Science and Technology of Welding and Joining ; Volume 20, Issue 6 , 2015 , Pages 512-521 ; 13621718 (ISSN) Alizadeh Sh, M ; Pouranvari, M ; Marashi, S. P. H ; Sharif University of Technology
    Maney Publishing  2015
    Implementation of new materials in automotive body-in-white requires through knowledge of their metallurgical response to welding process thermal cycle. This two-part paper aims at understanding the physical and mechanical metallurgy of stainless steels, as interesting candidates for automotive application, during resistance spot welding. The second part addresses the phase transformations in the heat affected zone of three types of stainless steels including austenitic, ferritic and duplex steels. Failure modes and mechanical properties of stainless steel resistance spot welds are discussed. The peak load and energy absorption of stainless steel resistance spot welds are compared with... 

    Welding metallurgy of dissimilar AISI 430/DQSK steels resistance spot welds

    , Article Welding Journal ; Volume 94, Issue 6 , 2015 , Pages 203s-210s ; 00432296 (ISSN) Pouranvari, M ; Marashi, S. P. H ; Alizadeh Sh, M ; Sharif University of Technology
    American Welding Society  2015
    This paper addresses the microstructure and mechanical performance of dissimilar resistance spot welds between AISI 430 ferritic stainless steel and drawing quality special killed (DQSK) low-carbon steel. The mechanical properties of the welds are described by peak load, failure energy, and failure mode during the tensile-shear test. Phase transformations in the fusion zone (FZ) and heat-affected zone (HAZ) are analyzed. The main metallurgical features of the weldment are the formation of a dual-phase, ferrite-martensite microstructure in the FZ, grain growth and martensite formation in the HAZ of the ferritic stainless steel side, and martensitic and eutectoid transformations in the HAZ of... 

    Simultaneous Analysis of Aliphatic Alcohols Mixtures Using an Electronic Nose Based on Nano/Microstructured Conducting Polypyrrole Film Prepared by Catalytic Electropolymerization on Cu/Au Interdigital Electrodes Using Multivariate Calibration

    , Article IEEE Sensors Journal ; Volume 16, Issue 2 , 2016 , Pages 418-425 ; 1530437X (ISSN) Alizadeh, N ; Babaei, M ; Alizadeh, M. S ; Mani Varnosfaderani, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2016
    In this paper, nano/microstructured-conducting polypyrrole has been prepared on Cu/Au interdigital electrode surfaces by using constant potential amperometry technique. The Fe(II) ions were used as catalyst and X = ClO4 -, pTs-, Cl-, TCA-, DS-, DBS- was implemented as anion dopants. The morphologies of the films were investigated by field emission scanning electron microscope. A remarkable dependence was observed between the type of anion dopant and the morphology of polypyrrole (PPy). The sensing behavior of the PPy-X sensor has been studied toward acetone, methanol, ethanol, 1-propanol, 2-propanol, nitromethane, propylamine, pyridine, and gas mixtures of aliphatic alcohols. The responses... 

    An ideal theoretic approach to complete partite zero-divisor graphs of posets

    , Article Journal of Algebra and its Applications ; Volume 12, Issue 2 , 2013 ; 02194988 (ISSN) Alizadeh, M ; Maimani, H. R ; Pournaki, M. R ; Yassemi, S ; Sharif University of Technology
    In this paper, we characterize complete partite zero-divisor graphs of posets via the ideals of the posets. In particular, for complete bipartite zero-divisor graphs, we give a characterization based on the prime ideals of the posets  

    Analytical approximate solution of the cooling problem by Adomian decomposition method

    , Article Communications in Nonlinear Science and Numerical Simulation ; Volume 14, Issue 2 , 2009 , Pages 462-472 ; 10075704 (ISSN) Alizadeh, E ; Sedighi, K ; Farhadi, M ; Ebrahimi Kebria, H. R ; Sharif University of Technology
    The Adomian decomposition method (ADM) can provide analytical approximation or approximated solution to a rather wide class of nonlinear (and stochastic) equations without linearization, perturbation, closure approximation, or discretization methods. In the present work, ADM is employed to solve the momentum and energy equations for laminar boundary layer flow over flat plate at zero incidences with neglecting the frictional heating. A trial and error strategy has been used to obtain the constant coefficient in the approximated solution. ADM provides an analytical solution in the form of an infinite power series. The effect of Adomian polynomial terms is considered and shows that the... 

    Aero-thermal redesign of a high pressure turbine nozzle guide vane

    , Article Propulsion and Power Research ; Volume 8, Issue 4 , 2019 , Pages 310-319 ; 2212540X (ISSN) Yavari, H ; Khavari, A ; Alizadeh, M ; Kashfi, B ; Khaledi, H ; Sharif University of Technology
    Elsevier Ltd  2019
    The current article presents conceptual, preliminary and detailed aero-thermal redesign of a typical high pressure turbine nozzle guide vane. Design targets are lower coolant consumption, reduced manufacturing costs and improved durability. These goals are sought by 25% reduction in vane count number and lower number of airfoils per segment. Design challenges such as higher airfoil loading, associate aerodynamic losses and higher thermal loads are discussed. In order to maximize coolant flow reduction and avoid higher aerodynamic losses, airfoil Mach distribution is carefully controlled. There has been an effort to limit design changes so that the proven design features of the original vane... 

    Experimental and simulation investigation of pulsed heat pipes in gas compressors

    , Article AIMS Energy ; Volume 8, Issue 3 , 2020 , Pages 438-454 Alizadeh, A ; Shafii, M. B ; Mirzahosseini, A. H ; Ataei, A ; Sharif University of Technology
    AIMS Press  2020
    In natural gas pressure boosting stations, air coolers are used to reduce the gas temperature. Pressure drop as an essential factor in determining the energy performance of any pressure boosting station has a significant impact on the overall performance of the gas transmission. In this paper, a laboratory pilot is designed to investigate the effect of pressure drop reduction on the use of heating pipes at the air coolers. In addition, as a case for a gas pressure boosting station, its impact over energy performance index and pressure drop parameter has been calculated through simulating. The results show, implemented PHP tubes in an air cooler, lead to reduce tube length and improve... 

    Effect of graphene oxide on morphological and structural properties of graphene reinforced novolac-derived carbon aerogels: A modified Quasi-Percolation Model

    , Article Ceramics International ; Volume 46, Issue 8 , 2020 , Pages 11179-11188 Alizadeh, O ; Madaah Hosseini, H. M ; Pourjavadi, A ; Bahramian, A. R ; Sharif University of Technology
    Elsevier Ltd  2020
    Graphene reinforced polymer derived carbon (carbon/graphene) aerogels were synthesized by carbonization of novolac/graphene oxide aerogels. Novolac/graphene oxide aerogels were synthesized using solvent-saturated-vapor-atmosphere technique. To this aim, 20 wt% solution of novolac resin with 0, 2, and 5 wt% graphene oxide in 2-propanol were made and were cured in an autoclave. Wet aerogels were dried in air and were carbonized at 800 °C in nitrogen atmosphere. Eliminating the time-consuming methods of drying like supercritical and freeze drying is one of the advantages of this method of synthesis of organic aerogles. Fourier transform infrared spectroscopy, field emission scanning electron... 

    The eco-efficiency assessment of wastewater treatment plants in the city of Mashhad using emergy and life cycle analyses

    , Article Journal of Cleaner Production ; Volume 249 , 2020 Alizadeh, S ; Zafari koloukhi, H ; Rostami, F ; Rouhbakhsh, M ; Avami, A ; Sharif University of Technology
    Elsevier Ltd  2020
    The aim of this study is to evaluate the sustainability of two actual wastewater treatment plants using the eco-efficiency index based on emergy and life cycle analysis. The life cycle analysis is used for environmental investigation to estimate the eco-efficiency index. Moreover, the emergy theory indicating the input and output flows of the ecosystem are applied to assess the sustainability considering ecosystem services. Two treatment plants are studied in the city of Mashhad in Iran. The potential for sustainability improvement of plants is analyzed in some scenarios including the production of agricultural compost from sludge, 10% reduction of energy consumption, and 10% reduction of... 

    High performance grout connection for pre-cast concrete structures

    , Article International Conference on Sustainable Construction Materials and Technologies, Coventry, 11 June 2007 through 13 June 2007 ; 2007 , Pages 479-485 ; 9780415446891 (ISBN) Alizadeh Kharazi, M ; Sharif University of Technology
    Connections have very important role in pre-cast concrete structures, especially in seismic zones, and grout connections increase strength and resistance of pre-cast concrete structures for lateral forces. High performance grout connections (HPGC) provide new opportunities to design cost-effective pre-cast concrete structures. HPGC have been proposed to decrease cost of insulation, erection and crane cost of pre-cast concrete structures and to overcome weakness of traditional pre-cast concrete structure connections .This research focuses on properties of grout materials properties which produced in Iran and the effect of propylene fiber on the performance of grout connection. In the first... 

    Recurrent poisson factorization for temporal recommendation

    , Article IEEE Transactions on Knowledge and Data Engineering ; 2018 ; 10414347 (ISSN) Hosseini, S ; Khodadadi, A ; Alizadeh, K ; Arabzadeh, A ; Farajtabar, M ; Zha, H ; Rabiee, H. R. R ; Sharif University of Technology
    IEEE Computer Society  2018
    Poisson Factorization (PF) is the gold standard framework for recommendation systems with implicit feedback whose variants show state-of-the-art performance on real-world recommendation tasks. However, most of the previous work do not explicitly take into account the temporal behavior of users which is essential to recommend the right item to the right user at the right time. In this paper, we introduce a Recurrent Poisson Factorization (RPF) framework that generalizes the classical PF methods by utilizing a Poisson process for modeling the implicit feedback. RPF treats time as a natural constituent of the model, and takes important factors for recommendation into consideration to provide a...