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    Simulation of Solar Hot Water System By TRNSYS-Case Study of Rahman Abad Park

    , M.Sc. Thesis Sharif University of Technology Khorrami Banadaki, Siamak (Author) ; Kazemzadeh Hannani, Siamak (Supervisor) ; Abbaspour, Majid (Supervisor)
    Abstract
    Limitations of fossil energy resources and environmental factors such as gas emission and global warming, forces human being to tend to apply renewable energies especially solar energy resource. Iran, which is located in yellow belt of the earth, has a high potential to be benefited from solar energy. Since more than 40 percent of energy resources are consumed in the building section, using solar energy I buildings can help the country to reduce the energy consumption. Space Cooling and heating and water heating are some examples of solar energy applications in buildings. Because, there are various types of climates in the world, there is not a unified code and guideline to design and... 

    Exact determination of the phase structure of a multi-species asymmetric exclusion process

    , Article Journal of Statistical Physics ; Volume 100, Issue 5-6 , 2000 , Pages 999-1030 ; 00224715 (ISSN) Khorrami, M ; Karimipour, V ; Sharif University of Technology
    Kluwer Academic/Plenum Publishers  2000
    Abstract
    We consider a multi-species generalization of the Asymmetric Simple Exclusion Process on an open chain, in which particles hop with their characteristic hopping rates and fast particles can overtake slow ones. The number of species is arbitrary and the hopping rates can be selected from a discrete or continuous distribution. We determine exactly the phase structure of this model and show how the phase diagram of the 1-species ASEP is modified. Depending on the distribution of hopping rates, the system can exist in a three-phase regime or a two-phase regime. In the three-phase regime the phase structure is almost the same as in the one species case, that is, there are the low density, the... 

    Microstructure evolutions and mechanical properties of tubular aluminum produced by friction stir back extrusion

    , Article Materials and Design ; Volume 65 , January , 2015 , Pages 74-79 ; 02613069 (ISSN) Sarkari Khorrami, M ; Movahedi, M ; Sharif University of Technology
    Elsevier Ltd  2015
    Abstract
    Aluminum tubes were successfully fabricated using a novel process of friction stir back extrusion (FSBE) known as one of the severe plastic deformation (SPD) routes. It was found that this process is capable to form a tube with a significant fine grained structure resulting from dynamic recrystallization phenomenon in the stirred area. Several regions were identified in the formed tube in which various microstructural evolutions occur, i.e. dynamic recrystallized (RX), static RX, and partially static RX zones along with extruded base metal. There was also no considerable change in the hardness and strength values of the formed tube with respect to those of the extruded base metal. However,... 

    Post deformation at room and cryogenic temperature cooling media on severely deformed 1050-aluminum

    , Article Metals and Materials International ; Volume 24, Issue 2 , 2018 , Pages 401-414 ; 15989623 (ISSN) Sarkari Khorrami, M ; Kazeminezhad, M ; Sharif University of Technology
    Korean Institute of Metals and Materials  2018
    Abstract
    The annealed 1050-aluminum sheets were initially subjected to the severe plastic deformation through two passes of constrained groove pressing (CGP) process. The obtained specimens were post-deformed by friction stir processing at room and cryogenic temperature cooling media. The microstructure evolutions during mentioned processes in terms of grain structure, misorientation distribution, and grain orientation spread (GOS) were characterized using electron backscattered diffraction. The annealed sample contained a large number of “recrystallized” grains and relatively large fraction (78%) of high-angle grain boundaries (HAGBs). When CGP process was applied on the annealed specimen, the... 

    Social Networks, Collaboration Graphs and Random Graphs

    , M.Sc. Thesis Sharif University of Technology Rasekhi KHorrami, Vista (Author) ; Mahmoodian, Ebadollah (Supervisor)

    Application of PSA Methods in the Reliability Analysis of EPSS of Busherhr NPP in case of Station Black Out

    , M.Sc. Thesis Sharif University of Technology Khorrami, Vahid (Author) ; Ghofrani, Mohammad Bagher (Supervisor)
    Abstract
    LOOP accident is one of the most important accidents in NPPS and it leads to loss of power supply of the RCP pumps which are the main pumps of primary circuit. Subsequently trip of the rector occurs. In safety analysis, concerning worst conditions, assumes that after a small period of time, main generator of plant stops working and loss of AC power supply of all power plant loads including safety systems ocures. To control of this accident, it’s necessary to startup and load backup power supply system (EDGs) for at least one safety channels, if not, the accident moves forwards and becomes S.B.O accident which is more important accident that ends to core damage because of stops working of all... 

    Externally driven one-dimensional Ising model

    , Article Journal of Statistical Mechanics: Theory and Experiment ; Volume 2012, Issue 2 , Feb , 2012 ; 17425468 (ISSN) Aghamohammadi, A ; Aghamohammadi, C ; Khorrami, M ; Sharif University of Technology
    2012
    Abstract
    A one-dimensional kinetic Ising model at a finite temperature on a semi-infinite lattice with time varying boundary spins is considered. Exact expressions for the expectation values of the spin at each site are obtained, in terms of the time dependent boundary condition and the initial conditions. The solution consists of a transient part which is due to the initial conditions, and a part driven by the boundary. The latter is an evanescent wave when the boundary spin is oscillating harmonically. Low-and high-frequency limits are investigated in greater detail. The total magnetization of the lattice is also obtained. It is seen that for any arbitrary rapidly varying boundary conditions, this... 

    Mechanical properties of graphene oxide: A molecular dynamics study

    , Article Fullerenes Nanotubes and Carbon Nanostructures ; Volume 24, Issue 9 , 2016 , Pages 594-603 ; 1536383X (ISSN) Khoei, A. R ; Sarkari Khorrami, M ; Sharif University of Technology
    Taylor and Francis Inc  2016
    Abstract
    In this paper, the mechanical properties of graphene oxide are obtained using the molecular dynamics analysis, including the ultimate stress, Young modulus, shear modulus and elastic constants, and the results are compared with those of pristine graphene. It is observed that the increase of oxide agents (–O) and (–OH) leads to the increase of C–C bond length at each hexagonal lattice and as a result, alter the mechanical properties of the graphene sheet. It is shown that the elasticity modulus and ultimate tensile strength of graphene oxides (–O) and (–OH) decrease significantly causing the failure behavior of graphene sheet changes from the brittle to ductile. The results of shear loading... 

    Strategic Requirements of Petroleum Upstream Supply Chain Management

    , M.Sc. Thesis Sharif University of Technology Khorrami, Hamed (Author) ; Fatahi Valilai, Omid (Supervisor)
    Abstract
    Nowadays the concept of competition in business has been expanded from enterprises to supply chains. For success in this competitive environment, it should be established complete coordination and synchronization between different rings of the chain in both strategy and operations. The supply chain management is a factor for achieving to this purpose. Effective supply chain management, especially in complex supply chains like petroleum upstream supply chain, requires to strategic factors that propel the chain to the long term goals. Unfortunately, it is showing off the vacancy of attending to this case in the literature. This thesis tries to fill this gap in literature with a new approach... 

    Finding the best alternative for plugging problem in MEG regeneration unit using AHP method

    , Article Society of Petroleum Engineers - SPE Russian Oil and Gas Technical Conference and Exhibition 2010, RO and G 10, 26 October 2010 through 28 October 2010, Moscow ; Volume 1 , 2010 , Pages 48-54 ; 9781617820441 (ISBN) Khorrami, Z ; Karimkhani, B ; Farhadi, F. A ; Sharif University of Technology
    2010
    Abstract
    MEG regeneration and injection unit regenerates aqueous MEG. The main goal of this unit is approaching desired MEG concentration whereas MEG loss via removed water is a big issue. Circulating glycol is polluted with Ca++ and Mg++ which forms carbonate scale and causes plugging of pipe lines, filters, lean/rich exchanger, still column packings and reboiler tube bundle and decreases their efficiency, consequently increases MEG loss via top product. Different alternatives exist according to similar experiences around the world. Using specific criteria and AHP (Analytical Hierarchy Process) method priority of these alternatives has been found. Results are as following: 1. Increasing number of... 

    Theoretical study of diffusional release of a dispersed solute from cylindrical polymeric matrix: A novel configuration for providing zero-order release profile

    , Article Applied Mathematical Modelling ; Volume 73 , 2019 , Pages 136-145 ; 0307904X (ISSN) Khorrami Jahromi, A ; Shieh, H ; Saadatmand, M ; Sharif University of Technology
    Elsevier Inc  2019
    Abstract
    In the context of controlled release drug delivery approaches, the systems providing zero-order release kinetics have special advantages. Through employing these systems, drug concentration could be maintained within the therapeutic window over release time; thus maximum effectiveness alongside minimized side effects of the drug are achieved. However, obtaining zero-order drug release is extremely challenging. One of the main obstacles is the fact that implemented devices should be designed to overcome the decreasing mass transfer driving force, especially, in polymeric systems in which diffusion mechanism is dominant. In this study, we developed a new configuration of a polymeric matrix... 

    Evaluating Dependability of Open-Source File Systems Considering Organizations of Hard Disks and Solid-State Drives

    , M.Sc. Thesis Sharif University of Technology Nouralizadeh Khorrami, Ahmad (Author) ; Asadi, Hossein (Supervisor)
    Abstract
    Storage subsystem is one of the most important components of a computer system. As more valuable information such as bank transactions are being stored in storage subsystems,occurrence of an unrecoverable error can lead to a much bigger problem. A storage subsystem can be divided into software and hardware part. Previous works focused on fault injection in the higher layers of the storage stack and didn’t consider fault injection at the device driver level. In this thesis, the dependability of storage stack is evaluated using fault injection at the device driver layer. Various hardware and software faults that can occur in hard disks and solid state drives are studied and dependability of... 

    Thermal stability of aluminum after friction stir processing with SiC nanoparticles

    , Article Materials and Design ; Volume 80 , September , 2015 , Pages 41-50 ; 02613069 (ISSN) Khorrami, M. S ; Kazeminezhad, M ; Kokabi, A. H ; Sharif University of Technology
    Elsevier Ltd  2015
    Abstract
    In this research, 1050 aluminum sheets in the conditions of annealed and severely deformed by 2 passes of constrained groove pressing (CGP) process were used. Two passes of friction stir processing (FSP) were applied on the specimens. Also, another CGPed specimen was processed by 2 passes of FSP using SiC nanoparticles. The samples were then heat treated to study thermal stability of base metal, heat affected zone (HAZ), thermo-mechanically affected zone (TMAZ), and stir zone (SZ). Microstructure examinations revealed that the annealed base metal was relatively stable upon heating even up to 400. °C and a little grain growth was evident. On the other hand, the CGPed base metal was fairly... 

    Mechanical properties of severely plastic deformed aluminum sheets joined by friction stir welding

    , Article Materials Science and Engineering A ; Volume 543 , 2012 , Pages 243-248 ; 09215093 (ISSN) Khorrami, M. S ; Kazeminezhad, M ; Kokabi, A. H ; Sharif University of Technology
    2012
    Abstract
    The severely plastic deformed aluminum sheets were joined by friction stir welding (FSW). The technique used for imposing the severe strain to the sheets was constrained groove pressing (CGP) process. The specimens with three different imposed strains by CGP, which lead to different initial microstructures, were joined at various rotation (. ω) and traveling (. V) speeds. The microhardness measurements and microstructure investigations were carried out. It was revealed that after FSW process of the specimens strained by CGP process, grain growth and correspondingly hardness reduction were observed at the stir zone. Also, transverse tensile test was performed at all conditions. For the CGPed... 

    Microstructure evolutions after friction stir welding of severely deformed aluminum sheets

    , Article Materials and Design ; Volume 40 , September , 2012 , Pages 364-372 ; 02641275 (ISSN) Sarkari Khorrami, M ; Kazeminezhad, M ; Kokabi, A. H ; Sharif University of Technology
    Elsevier  2012
    Abstract
    The microstructure evolutions of severely deformed aluminum sheets by Constrained Groove Pressing (CGP) after Friction Stir Welding (FSW) are investigated. To do so, the specimens are deformed in three different strains using CGP process which make different the initial microstructures. Then, the specimens are joined at various revolution pitches (traveling speed/rotation speed ratio) of 0.20, 0.25 and 0.33. mm/r. To understand the effect of initial strains on the properties of joints, the microhardness measurements and microstructure investigations of different areas from retreating to advancing sides of the joints are carried out. The results achieved from FSW of CGPed samples are compared... 

    Study on joint interface and mechanical properties of cu/pb-sn/cu lap joint produced by friction stir soldering process

    , Article Journal of Materials Engineering and Performance ; Volume 24, Issue 5 , May , 2015 , Pages 2158-2169 ; 10599495 (ISSN) Sarkari Khorrami, M ; Kokabi, A. H ; Movahedi, M ; Sharif University of Technology
    Springer New York LLC  2015
    Abstract
    In this work, friction stir soldering (FSS) as a new approach for fabrication of copper/copper lap joints was introduced. This process is principally based on the friction stir processing (FSP) that can be performed using FSP tools with and without pin on the top sheet. In the present study, Pb-Sn foil was used as a solder which would be melted and then extruded in the area between the copper sheets during FSS process. This process was carried out using tools with and without pin at various rotation speeds of 1200, 1400, and 1600 rpm and traverse speed of 32 mm/min. Also, the same joint was fabricated using furnace soldering to compare the mechanical properties obtained with FSS and furnace... 

    Influence of stored strain on fabricating of Al/SiC nanocomposite by friction stir processing

    , Article Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science ; Volume 46, Issue 5 , May , 2015 , Pages 2021-2034 ; 10735623 (ISSN) Khorrami, M. S ; Kazeminezhad, M ; Kokabi, A. H ; Sharif University of Technology
    Springer Boston  2015
    Abstract
    In this work, 1050 aluminum (Al) sheets were annealed and severely deformed by 1, 2, and 3 passes of constrained groove pressing process to obtain the various initial stored strain values of 0, 1.16, 2.32, and 3.48, respectively. Friction stir processing (FSP) was then applied using SiC nanoparticles to fabricate Al/SiC nanocomposite with approximately 1.5 vol pct reinforced particles. Microstructural examinations revealed that an increase in the initial stored strain of the base metal led to the formation of finer grain structure after 1 pass of FSP. The finer grain structure occurred in the stir zone where a sufficient amount of nanoparticles with a relatively proper distribution existed.... 

    Hierarchical Multiscale Modeling in Large and Plastic Deformations

    , M.Sc. Thesis Sharif University of Technology Sarkari Khorrami, Mohammad (Author) ; Khoei, Amir Reza (Supervisor)
    Abstract
    In this study, the hierarchical multiscale method is presented to model macro-scale materials with considering large and plastic deformations. Since the classic methods such as continuum mechanics were unable to model defects such as dislocations, voids, and etc. at nano scale. Also, the molecular dynamics methods have high computational costs; hence, recearchers try to develop multiscale methods in order to utilize them. Multiscale modeling in which two scales are considered and some information be transferred from fine scale to coarse scale. In this work, the coarse scale is modeled by finite element method (FEM) and the fine scale is analysed by molecular dynamics (MD). In fact, two... 

    Seismic Performance of Composite Frames Consisting of Reinforced Concrete Columns and Steel Beams

    , M.Sc. Thesis Sharif University of Technology Mosleh Khorrami, Kamran (Author) ; Kazemi, Mohammad Taghi (Supervisor)
    Abstract
    Composite systems consisting of concrete columns and steel beams are introduces as structural systems in recent years. These structural systems enjoy merits of both steel and concrete frames by efficiently combining the advantages of them. This study is allocated to lateral force resistance system using armed concrete and structural steel. Advantages of composite structures rather to those of two other conventional ones are among performance characteristics under ultimate loads, economical conservation, and higher speed of construction.In this research the aim is to study these frame under earthquake induced loads. The seismic performances of these composite frames with through column beams,... 

    Thermal stability during annealing of friction stir welded aluminum sheet produced by constrained groove pressing

    , Article Materials and Design ; Volume 45 , 2013 , Pages 222-227 ; 02613069 (ISSN) Sarkari Khorrami, M ; Kazeminezhad, M ; Kokabi, A. H ; Sharif University of Technology
    2013
    Abstract
    The severely deformed aluminum sheets with strain of 2.32 were successfully joined by friction stir welding (FSW) process. Welding was carried out at various rotation speeds of 600, 800, and 1000. rpm at traveling speed of 200. mm/min corresponding to various revolution pitches of 0.33, 0.25, and 0.20. mm/r, respectively. In order to investigate the thermal stability of the joints, annealing was carried out at temperature of 200 °C for 1. h. Microstructure examinations revealed that severely deformed samples were quite unstable upon FSW process. However, during annealing it was found that in contrast to regions of heat affected zone (HAZ) and thermo mechanical affected zone (TMAZ) where...