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    Optimum receiver design for transmitted-reference signaling [electronic resource]

    , Article IEEE Transactions on Communications ; May 2010, Volume 58, Issue 5, P.1589-1598 Farhang, M. (Mahmoud) ; Salehi, J. A ; Sharif University of Technology
    Abstract
    Autocorrelation receiver (AcR) is usually used as the general receiver for transmitted reference (TR) communication systems on a quite intuitive basis. In this paper, we apply the principle of statistical invariance to obtain the optimum TR receiver on a decision-theoretic basis, and it is shown that the autocorrelation receiver is optimal only in a special case. Performance of the optimum receiver and the suboptimum AcR for some important modulation schemes is also evaluated. The results imply that allocating a part of the transmitted energy and bandwidth to reference pulses would not help improve the performance of the system and the optimal performance might be achieved via much simpler... 

    Electromagnetic performance, optical and physiochemical features of CaTiO3/NiO and SrFe12O19/NiO nanocomposites based bilayer absorber

    , Article Journal of Colloid and Interface Science ; 2021 ; 00219797 (ISSN) Feng, L ; Liu, J ; Huynen, I ; Mahmoud, M. Z ; Niaz Akhtar, M ; Sharif University of Technology
    Academic Press Inc  2021
    Abstract
    Herein, two distinct nanocomposites of CaTiO3 micro-cubes and polygonal SrFe12O19, both decorated with NiO nanoparticles, were successfully synthesized using hydrothermal method. The physico-chemical features of as-prepared samples were evaluated via XRD, FTIR, UV–vis, BET, XPS, FESEM and EDS analysis. Microwave attenuation features of as-prepared single layer absorbers were determined by VNA analysis in 2–18 GHz. Simulation confirmation was checked by preparing a bi-layer samples and evaluating it using VNA analysis after finding the appropriate thickness of each layer. The reflection loss from each single layer samples containing 20 wt% of each CaTiO3/NiO and SrFe12O19/NiO nanocomposites... 

    Enhanced electromagnetic wave dissipation features of magnetic Ni microspheres by developing core-double shells structure

    , Article Ceramics International ; Volume 48, Issue 1 , 2022 , Pages 446-454 ; 02728842 (ISSN) Zhang, B ; Mahariq, I ; Tran, N ; Mahmoud, M. Z ; Akhtar, M. N ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    Readily oxidization of magnetic particles is a common drawback of these type of materials which reduce their electromagnetic wave dissipation performance. In this study, the magnetic core-double shells structured (Ni/SiO2/Polyaniline) composite has been developed for protection of the core from oxidation and in consequent improvement the complex permittivity. Solvothermal and in-situ polymerization methods were utilized for decorating Ni micro-particles with SiO2 and conductive polyaniline polymer respectively. All physico-chemical, magnetic and electromagnetic features were evaluated via XRD, FTIR, XPS, FESEM, VSM and VNA analysis. The double shells composite possesses significant... 

    Electromagnetic performance, optical and physiochemical features of CaTiO3/NiO and SrFe12O19/NiO nanocomposites based bilayer absorber

    , Article Journal of Colloid and Interface Science ; Volume 610 , 2022 , Pages 879-892 ; 00219797 (ISSN) Feng, L ; Liu, J ; Huynen, I ; Mahmoud, M. Z ; Akhtar, M. N ; Sharif University of Technology
    Academic Press Inc  2022
    Abstract
    Herein, two distinct nanocomposites of CaTiO3 micro-cubes and polygonal SrFe12O19, both decorated with NiO nanoparticles, were successfully synthesized using hydrothermal method. The physico-chemical features of as-prepared samples were evaluated via XRD, FTIR, UV–vis, BET, XPS, FESEM and EDS analysis. Microwave attenuation features of as-prepared single layer absorbers were determined by VNA analysis in 2–18 GHz. Simulation confirmation was checked by preparing a bi-layer samples and evaluating it using VNA analysis after finding the appropriate thickness of each layer. The reflection loss from each single layer samples containing 20 wt% of each CaTiO3/NiO and SrFe12O19/NiO nanocomposites... 

    FPGA-based fast detection with reduced sensor count for a fault-tolerant three-phase converter

    , Article IEEE Transactions on Industrial Informatics ; Volume 9, Issue 3 , 2013 , Pages 1343-1350 ; 15513203 (ISSN) Mahmoud, M ; Philippe, P ; Shahrokh, S ; Mohammad Reza, M. R ; Sharif University of Technology
    2013
    Abstract
    Fast fault detection (FD) and reconfiguration is necessary for fault tolerant power electronic converters in safety critical applications to prevent further damage and to make the continuity of service possible. The aim of this study is to minimize the number of the used additional voltage sensors in a fault tolerant three-phase converter. In this paper, first a practical implementation of a very fast FD scheme with reduced sensor number is discussed. Then, an optimization in this scheme is also presented to decrease the detection time. For FD, special time and voltage criterion are applied to observe the error in the estimated phase-to-phase voltages for a specific period of time. The... 

    The Feasibility Study of Micronized Powder Plant for Exporting (UNIDO METOD)

    , M.Sc. Thesis Sharif University of Technology (Author) ; Hooshmand, Mahmoud (Supervisor)
    Abstract
    This thesis deals with the development of a hypothetical micronized powder factory and trying to test and engage in this hypothetical development of the following plant, it considers following factors:
    1-Domestic & International market
    2-Plant location
    3-Plant design & development
    a.machinery
    b.technology & equipment
    c.human resource
    d.environment
    e.packing
    4-raw material
    5-shipping & transport
    To evaluate above factors the UNIDO methodology is used in this research work. The UNIDO methods are using a process by which feasibility studies of production facilities or plant are base on. After reviewing a variety of factors, ranging from financial... 

    Magnetic, structural, optical band alignment and conductive analysis of graphene-based REs (Yb, Gd, and Sm) doped NiFe2O4 nanocomposites for emerging technological applications

    , Article Synthetic Metals ; Volume 284 , 2022 ; 03796779 (ISSN) Akhtar, M. N ; Yousaf, M ; Lu, Y ; Mahmoud, M. Z ; Iqbal, J ; Khan, M. A ; Khallidoon, M. U ; Ullah, S ; Hussien, M ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    The productive and straightforward strategy was developed to fabricate graphene based NiFe2O4 doped rare-earth (RE) ions nanocomposites for enhancing the magnetic and structural characteristics of ferrites. RE nanoparticles (NPs) such as Yb3+, Gd3+ and Sm3+ were doped in NiFe2O4 ferrite structure via sol-gel auto-combustion method and hydrothermal method was utilized to fabricate their graphene-based nanocomposites. The weight loss and decomposition of the nanocomposites were determined using temperature-dependent thermo gravimetric analysis (TGA/DTA). The single-phase structure of the NiFe2O4, NiFe2O4/G, Yb doped NiFe2O4/G, Gd doped NiFe2O4/G, and Sm doped NiFe2O4/G nanocomposites was... 

    Feasibility Study Of A Gas To Liquid Plant

    , M.Sc. Thesis Sharif University of Technology Vahidian, Somayeh (Author) ; Hooshmand, Mahmoud (Supervisor)
    Abstract
    The methodology proposed by UNIDO , to investigate feasibility study of industrial project, is a useful tool in pre-investment decision making. In this work feasibility of investing on "Gas To Liquid" GTL Plant of Asalouye is investigated. Having gathered required information, including gas field potential, required technology and machineries, cost of investments , required manpower to run the UNIDO methodology is used to investigate the investment, the result of the work shows that the project is feasible and it would have internal rate of return of 24% ( by sale cost= 81 $ per barrel of GTL product)  

    The Inverse Electromagnetic Scattering Problem

    , M.Sc. Thesis Sharif University of Technology Sajedi, Masoumeh (Author) ; Hesaaraki, Mahmoud (Supervisor)

    Simulation of Transient Flow in Deformable Pipes and Networks

    , M.Sc. Thesis Sharif University of Technology Niroomandi, Arash (Author) ; Borghei, Mahmoud (Supervisor)
    Abstract
    Water hammer is a pressure surge or wave resulting when a pressurized fluid in motion is forced to stop or change direction suddenly. This phenomenon can cause great amount of damage to the system and should be considered in designing of pipe systems. So, researchers have derived and proposed numerous models using different approaches. In this study a one-dimensional model using Time Splitting Method (TSM) and Double Sweep Method (DSM) are proposed to simulate transient flow in deformable pipes in networks. To solve the equations of momentum and continuity TSM is applied. In addition Brunone model is used to study the effect of unsteady friction on water hammer wave shape and attenuation. To... 

    Qualitative and Topological Properties of Some Partial Differential Equations

    , M.Sc. Thesis Sharif University of Technology Moameni, Abbas (Author) ; Hesaaraki, Mahmoud (Supervisor)
    Abstract
    This thesis is devoted to prove the existance of solution and structure of solu­ tion for some partial differential equations by using some modern topological and variational thechniques. Taking direction from the literature, this thesis is interested in existence, uniqueness, blow-up in finite time for some evolution equations, multiplicity and radial solution for certain elliptic partial differential equations.-Employing Fibrering, Galerkins, Mountain Pass-Lemma and lions com­ pactness Lemma are sharp in this thesis to prove the exsistence and multiplicity of solutions and overcome lack of compactness in some cases  

    Development and Implement Ation of TPM in Aabsal Company

    , M.Sc. Thesis Sharif University of Technology Safaieh, Mehrdad (Author) ; Hushmand, Mahmoud (Supervisor)
    Abstract
    Aabsal Co. was established in north east of Tehran in 1956, under the name of Loab Iran Private LTD.  Co.  and  continued  its  activity  in  manufacturing  enameled  dishes,  bowl,  tea  pots  and  etc.  until 1964. In  this  thesis  we  have  paid  attention  to  basics  of  TPM  and  how  to  implement  PM  procedures.  First we have paid attention to all the maintenance forms and how these forms work together in the company, and then the relationship between departments sections like manufacturing and maintenance are considered. Finally we have attempted to implement TPM. For this purpose we have taken a section of the factory as a pilot plant and have started to implement TPM there to... 

    Evaluating the Leanness and Agility Indexes of S.G.S Co

    , M.Sc. Thesis Sharif University of Technology Lotfi, Maryam (Author) ; Houshmand, Mahmoud (Supervisor)
    Abstract
    In this research ,lean and agile indexes in S.G.S Co. are evaluated. This company is the first company in engineering and supplying automotive parts as well as the first supply chain management and organization of Saipa Group. In the part of evaluating the lean management level it is the developed model of the suggested approach by Jackson “implementing a lean management system” (Jackson, 1996). As S.G.S is engaged in servicing activities not in production, we have changed some factors in Jackson's methodology. Different with the last model, we got the results and used AHP method for getting the level in each key. Finally by using another AHP the lean index of the S.G.S Co. was identified.... 

    An optimal Liouville-Type Theorem for Radial Entire Solutions of the Porous Medium Equation with Source

    , M.Sc. Thesis Sharif University of Technology Ansari, Hajar (Author) ; Hesaraki, Mahmoud (Supervisor)
    Abstract
    In this thesis , we consider nonnegative (continuous) weak solutions of the porous medium equation with source , u_t-∆u^m=u^p, and p>m>1 .
    Assume that, m>1 and 1< p/m u_t-∆u^m=u^p,xϵR^n ,tϵR
    has no nontrivial, bounded radial solutions u≥0 .
    In one space-dimensional, the conclusion of the result mentioned above remains true without the assumption of the radial symmetry. The proof is based on the intersection-comparison arguments , zero number argum- ents and a key step is to show the... 

    , M.Sc. Thesis Sharif University of Technology Kelaretaghi, Naghi (Author) ; Hesaraki, Mahmoud (Supervisor)
    Abstract
    Our problem is to evaluation state and form of a tracer passing through the vessel. Using this method, we can identify the effect of during used in some defected parts of body. This evaluation leads to in solving a Laplace equation with mixed boundary condition. Separating that problem, we reach to a collection of algebraic and linear equations. Solving this system, we approximate coefficients of the solution with a series the existence and uniqueness of and analytic solution has been proved using the Eigen functions finally, using numerical algorithms, we have interpreted the analytical solutions.
     

    Existence and Uniqueness of Solution for Two Free Boundary Problems Modelling Tumor Growth

    , M.Sc. Thesis Sharif University of Technology Esmaili, Sakine (Author) ; Hesaaraki, Mahmoud (Supervisor)
    Abstract
    This thesis is based on articles [18,15]. Zhao [18] has studied a free boundary problem modeling the growth of tumors with drug application. In this model live cells are two kindes: proliferative cells and quiescent cells. This model consists of two nonlinear second-order parabolic equations describing the diffusion of nutrient and drug concentration, and three nonlinear first-order hyperbolic equations describing the evolution of proliferative cells, quiescent cells and dead cells. He has proved that this free boundary problem has a unique global solution. Tao and Chen [15] have studied another free boundary problem modelling the growth of an avascular tumour with drug application. The... 

    Nonhomogeneous Boundary Value Problems for some Nonlinear Equations with Singular Ø-Laplacian

    , M.Sc. Thesis Sharif University of Technology Jannat, Farzaneh (Author) ; Hesaaraki, Mahmoud (Supervisor)

    Carrying Capacity of Perforated Pipes in Submerged Area

    , M.Sc. Thesis Sharif University of Technology Nabaei, Milad (Author) ; Borghei, Mahmoud (Supervisor)
    Abstract
    Selective withdrawal from water and settlement reservoirs and tanks is necessary for water and environmental systems. Perforated pipes can be used for selective withdrawal within the length of these reservoirs. In this method, the lateral inflow through perforations leads to the outlet of the pipe that is placed in a depth of fluid. In relation to the hydraulics of perforated pipes, most studies are about drainage pipes and perforated pipes that are used as wellbores in horizontal wells, but application of these pipes have not been investigated in submerged situations. Capacity estimation of perforated pipes based on inside diameter of the pipe, material of the pipe, perforations of the... 

    Integrated Process Planning System for Prismatic Parts Based on STEP

    , M.Sc. Thesis Sharif University of Technology Foroozmand, Hamzeh (Author) ; Houshmand, Mahmoud (Supervisor)
    Abstract
    Nowadays, as a result of rapid changes of market, it is necessary to reduce the period between design and manufacturing of a new product. Among them, process planning is one of the most difficult elements of production chain and also, there are a few numbers of experts in this field. In addition, this process is time-consuming and costly. So, it is important for companies to reduce the period of new product’s presentation by reduction of process planning duration. On the other hand, it is proved that the lowest level of integration in CIM systems is in CAPP section. Integration provides sharing data in the system, so the other parts of production systems can exchange product information and... 

    Exponential Stability of Hopfield Neural Network with Impulses

    , M.Sc. Thesis Sharif University of Technology Saramad, Neda (Author) ; Hesaraki, Mahmoud (Supervisor)
    Abstract
    In this paper, the Hopfield neural network models have investigated. Also the similar model with time -varying delays and constant coefficients has considered and with establishing some criterions, existence solution and it's exponential stability of the solution is investigated. Moreover, some special conditions for exponential stability by impulses and exponential stability by periodic impulses are obtained