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    A non-homogeneous Hill's equation

    , Article Applied Mathematics and Computation ; Volume 167, Issue 1 , 2005 , Pages 68-75 ; 00963003 (ISSN) Shadman, D ; Mehri, B ; Sharif University of Technology
    2005
    Abstract
    The existence of periodic solutions for a forced Hill's equation is proved. The proof is then extended to the case of a non-homogeneous matrix valued Hill's equation. Under the stated conditions, using Lyapunov's criteria [Proc. AMS 13 (1962) 601; Hill's Equation, Interscience Publishers, New York, 1966] some results on the stability oh Hill's equation are obtained. © 2004 Elsevier Inc. All rights reserved  

    A change point method for monitoring generalized linear profiles in phase I

    , Article Quality and Reliability Engineering International ; Volume 31, Issue 8 , 2015 , Pages 1367-1381 ; 07488017 (ISSN) Shadman, A ; Mahlooji, H ; Yeh, A. B ; Zou, C ; Sharif University of Technology
    2015
    Abstract
    The Phase I applications of the statistical profile monitoring have recently been extended to the case when the response variable is binary. We are motivated to undertake the current research in an attempt to try to provide a unified framework for the Phase I control in the context of statistical profile monitoring that can be used to tackle a large class of response variables, such as continuous, count, or categorical response variables. The unified framework is essentially based on applying the change point model to the class of generalized linear models. The proposed Phase I control chart is assessed and compared with the existing charts under binomial and Poisson profiles. Some... 

    A change point method for phase II monitoring of generalized linear profiles

    , Article Communications in Statistics: Simulation and Computation ; Volume 46, Issue 1 , 2017 , Pages 559-578 ; 03610918 (ISSN) Shadman, A ; Zou, C ; Mahlooji, H ; Yeh, A. B ; Sharif University of Technology
    2017
    Abstract
    In this article, we adopt the change point approach to monitor the generalized linear profiles in phase II Statistical process control (SPC). Generalized linear profiles include a large class of profiles defined in one framework. In contrast to the conventional change point approach, we adopt the Rao score test rather than the likelihood ratio test. Simulated results show that our approach has a good performance over any possible single step change in process parameters for two special cases of generalized linear profiles, namely Poisson and binomial profiles. Some diagnostic aids are also given and a real example is introduced to shed light on the merits of our approach in real... 

    Thermal Behavior of Rechargeable Li-ion Batteries; Experimental Evaluations and Modeling

    , Ph.D. Dissertation Sharif University of Technology Shadman Rad, Mojtaba (Author) ; Baghalha, Morteza (Supervisor) ; Kazemeini, Mohammad (Co-Advisor)
    Abstract
    The main objective of this research is to experimentally evaluate thermal behavior of commercially available rechargeable Li-ion batteries based on minimum measurements on main battery parameters and then develop experimental based models to investigate their thermal behavior. Li-ion batteries with Graphit anodes and Li(Ni0.8¬Co0.15Al0.05)O2 cathodes will be used for this purpose. Voltage and temperature developments during cycling under various currents at controlled ambient temperatures are measured by battery tester. Measurements show that temperature evolutions demonstrate falls and rises at specific State-of-Charge (SoC) of the battery during cycling and therefore some heat consumers... 

    Monitoring Generalized Linear Profiles Using Change-Point Approach

    , M.Sc. Thesis Sharif University of Technology Shadman, Alireza (Author) ; Mahlooji, Hashem (Supervisor) ; Akhavan Niaki, Taghi (Co-Advisor)
    Abstract
    There are many cases in industrial and non-industrial sections where the quality characteristics are in the form of profiles. A profile is the functional relationship between a response variable and one or more predictor variables used to describe the quality of a process. Profile monitoring is the implementation of statistical process control techniques for this purpose. According to the type of relationship between response variable and predictor variables, profiles are classified into many categories such as: simple linear profiles, multiple linear profiles, nonlinear profiles and generalized linear profiles. Most of the research efforts in the area of profile monitoring have been... 

    Modeling Kidney Vascular Structure Based on Parametric L-system

    , M.Sc. Thesis Sharif University of Technology Shadman, Shahriar (Author) ; Farhadi, Fatolah (Supervisor) ; Bozorgmehry Boozarjomehry, Ramin (Supervisor)
    Abstract
    Kidney is one of the most complicated organs in terms of functionality and physiology due to its complicated unique vascular structure. Previous investigations have focused on specific characteristics like length and diameter. Most of these methods are based on Image Processing techniques which prevent a comprehensive study in growth and changes of the vascular system. Lindenmyaer system (L-system) is a parallel rewriting system and a type of formal grammar and had been used to create graphs and natural patterns. By absorbing the physiological characteristics of the kidney and integrating them into parametric L-system, a highly dense and accurate vascular system could be generated with few... 

    Developing a novel colloidal model for predicting asphaltene precipitation from crude oil by alkane dilution

    , Article Journal of Molecular Liquids ; Volume 318 , 2020 Shadman, M. M ; Badizad, M. H ; Dehghanizadeh, M ; Saeedi Dehaghani, A. H ; Sharif University of Technology
    Elsevier B.V  2020
    Abstract
    This research aims to propose a thermodynamic model for predicting asphaltene precipitation upon diluting a crude oil with a paraffinic solvent. To this end, a thorough mathematical formulation was carried out to derive a novel micellization model based on the associative properties of asphaltenic compounds. It was assumed that asphaltenes exist in the oil both as monomeric molecules and aggregated cores; with stabilization latter by attachment of resin on its periphery. The aggregation equilibrium was established by taking into account asphaltene's lyophobic tendency, heat of resin adsorption, and interfacial tension between micelle and oil media which is the main driving factor... 

    Numerical simulation using a modified solver within OpenFOAM for compressible viscous flows

    , Article European Journal of Computational Mechanics ; Volume 28, Issue 6 , 2020 , Pages 541-572 Ghazanfari, V ; Salehi, A. A ; Keshtkar, A ; Shadman, M. M ; Askari, M. H ; Sharif University of Technology
    River Publishers  2020
    Abstract
    In this work, we attempted to develop an Implicit Coupled Density-Based (ICDB) solver using LU-SGS algorithm based on the AUSM+ up scheme in OpenFOAM. Then sonicFoam solver was modified to include viscous dissipation in order to improve its capability to capture shock wave and aerothermal variables. The details of the ICDB solver as well as key implementation details of the viscous dissipation to energy equation were introduced. Finally, two benchmark tests of hypersonic airflow over a flat plate and a 2-D cylinder were simulated to show the accuracy of ICDB solver. To verify and validate the ICDB solver, the obtained results were compared with other published experimental data. It was... 

    Adaptive thermal modeling of Li-ion batteries

    , Article Electrochimica Acta ; Volume 102 , 2013 , Pages 183-195 ; 00134686 (ISSN) Shadman Rad, M ; Danilov, D. L ; Baghalha, M ; Kazemeini, M ; Notten, P. H. L ; Sharif University of Technology
    2013
    Abstract
    An accurate thermal model to predict the heat generation in rechargeable batteries is an essential tool for advanced thermal management in high power applications, such as electric vehicles. For such applications, the battery materials' details and cell design are normally not provided. In this work a simple, though accurate, thermal model for batteries has been developed, considering the temperature- and current-dependent overpotential heat generation and State-of-Charge dependent entropy contributions. High power rechargeable Li-ion (7.5 Ah) batteries have been experimentally investigated and the results are used for model verification. It is shown that the State-of-Charge dependent... 

    Modeling and simulation of flow and uranium isotopes separation in gas centrifuges using implicit coupled density-based solver in OpenFOAM

    , Article European Journal of Computational Mechanics ; Volume 29, Issue 1 , 2020 , Pages 1-26 Ghazanfari, V ; Salehi, A. A ; Keshtkar, A. R ; Shadman, M. M ; Askari, M. H ; Sharif University of Technology
    River Publishers  2020
    Abstract
    The performance of a gas centrifuge that is used for isotopes separation is dependent on the gas flow inside it. In this study, for modeling the UF6 gas flow, an Implicit Coupled Density-Based (ICDB) solver, was developed in OpenFOAM. To validate the ICDB solver, the gas flow within the rotor in total reflux state was compared with the analytical solution obtained by Onsager model and the numerical solution obtained by the Fluent software. The results showed that the ICDB solver had acceptable accuracy and validity. Also the computational efficiency of Roe, AUSM (Advection Upstream Splitting Method) and AUSM+ up schemes were compared. The results showed AUSM+ up scheme is efficient. Then,... 

    Investigation of the continuum-rarefied flow and isotope separation using a hybrid CFD-DSMC simulation for UF6 in a gas centrifuge

    , Article Annals of Nuclear Energy ; 2020 Ghazanfari, V ; Akbar Salehi, A ; Reza Keshtkar, A ; Mahdi Shadman, M ; Hossein Askari, M ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    UF6 gas flow in the total regions of a rotor with the radius of 0.1 m and the length of 1 m in axisymmetric and steady states was simulated using a new hybrid CFD-DSMC method in the OpenFOAM framework. Implicit coupled density-based scheme was performed for CFD method, and Variable Hard Sphere (VHS) and diffuse model were employed in DSMC method. Also, as an initial estimation, the local Knudsen number was applied to determine the interface location between the continuum-rarefied regions (r = 0.0855 m). Then it was modified (r = 0.084 m) to reduce the computational cost. The comparison results of pure CFD and CFD-DSMC methods illustrated that there were large differences between the flow... 

    Investigation of the continuum-rarefied flow and isotope separation using a hybrid CFD-DSMC simulation for UF6 in a gas centrifuge

    , Article Annals of Nuclear Energy ; Volume 152 , 2021 ; 03064549 (ISSN) Ghazanfari, V ; Akbar Salehi, A ; Reza Keshtkar, A ; Mahdi Shadman, M ; Hossein Askari, M ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    UF6 gas flow in the total regions of a rotor with the radius of 0.1 m and the length of 1 m in axisymmetric and steady states was simulated using a new hybrid CFD-DSMC method in the OpenFOAM framework. Implicit coupled density-based scheme was performed for CFD method, and Variable Hard Sphere (VHS) and diffuse model were employed in DSMC method. Also, as an initial estimation, the local Knudsen number was applied to determine the interface location between the continuum-rarefied regions (r = 0.0855 m). Then it was modified (r = 0.084 m) to reduce the computational cost. The comparison results of pure CFD and CFD-DSMC methods illustrated that there were large differences between the flow... 

    Rcci Curvature for Metric-Measure Space via Optimal Transport

    , M.Sc. Thesis Sharif University of Technology Taheri, Abolfazl (Author) ; Bahraini, Alireza (Supervisor) ; Ranjbar Motlagh, Alireza (Co-Advisor)
    Abstract
    One of the important questions in mathematics is generalized. In case of metric spaces, one of the questions is: Can we extend notions of Riemannian geometry to arbitrary metric spaces smoothly? Ricci curvature is one of the most important concepts in differential geometry. Ricci curvature is defined for the Riemannian manifold and has many applications in mathematics and physics like Einstein’s equation in relativity theory. There is a good notion for a metric space having “sectional curvature bounded below by K” or “sectional curvature bounded above by K”, due to Alexandrov. Can we define the concept of Ricci curvature in metric space? A motivation for this question comes from Gromov’s... 

    , M.Sc. Thesis Sharif University of Technology (Author) ; Khaloo, Alireza (Supervisor)
    Abstract
    Seismic design codes reduce loads by using response modification factor. Because of the reserved strength in structural elements and capacity of structure to dissipate energy, structures can be designed for lower seismic loads. This factor has modified over time. In this thesis, the effect of the reduction in behavior factor on the response of two kinds of reinforced concrete systems were evaluated. Moment resisting frames and dual systems with different heights and regularity in plan, heve been design according to the behavior factor which is recommended in the 3rd edition of the Iranian codes of practice for seismic resistance design of buildings (Standard No. 2800). Drift and... 

    Prediction of Financial Markets Using Combination of Artificial Intelligence and Technical Analysis

    , M.Sc. Thesis Sharif University of Technology (Author) ; Haji, Alireza (Supervisor)
    Abstract
    Generally, nowadays, machine learning methods are used in many different areas for their superiority over other methods of prediction. Although being a tough task, stock market prediction with machine learning approaches is being spread due to satisfying results published ever yday. Machine learning methods usually use varied kinds of data ,including structured data such as market data, technical indicators and some fundamental data as well as unstructured one entailing text and graph data in order to enhance their predictability capacity. In this thesis we aimed to find out more about the importance and the contribution of structured data in prediction and we tried to attain a framework... 

    , M.Sc. Thesis Sharif University of Technology (Author) ; Hajji, Alireza (Supervisor)
    Abstract
    This thesis presents an inventory control system which is based on Meta-heuristic Algorithms.In this thesis we will optimize the input values of our tree-echelon inventory model (keeping costs,stock worth,reorder costs,...) with these Algorithms. The presented method is able to determine the optimal stock level, costs of system and number of shipments in the system. The method is basically a decision support system (DES) and it is able to provide the order scheduling parameters of goods at operational level. The aim of the current research is to demonstrate that a Meta-heuristic algorithmis capable of solving complex inventory problems and with future improvements it is able to achieve... 

    The Ricci Flow with Applications to the Poincare and Calabi Conjectures

    , M.Sc. Thesis Sharif University of Technology Safdari, Mohammad (Author) ; Bahreini, Alireza (Supervisor)
    Abstract
    Poincare conjecture is one of the rst eorts for classifying 3-manifolds that was stated in the begining of 20th century. Eorts for proving this conjecture continued for about 100 years and nally Perelman has solved it in 2003. He has used Ricci ow which has been invented by Richard Hamilton in the early 80's. In this thesis rst we will introduce Ricci ow and will state the results before Perelman such as short time and long time existence of solution. Then we will mention some applications of Ricci ow and will state an explanation of the proof of uniformization and Calabi conjecture by Ricci ow. After that we start the main part of the thesis. In this part we will montion one of the... 

    Feasibility And Study(CNG Cylinder Production Plant)

    , M.Sc. Thesis Sharif University of Technology Mousavi, Mohammad (Author) ; Haji, Alireza (Supervisor)
    Abstract
    Nowadays best using of fossil fuels sources of the country (and) importance of comparison against lack of capacity in petrol production make determined the programmers and the directors to foresee and design expanded programs of the goals, to use natural gas for car fuels. To reach fulfillment of these programs, the confirmed needs of the natural gas cylinders are improved and make it essential to invest on producing compressive natural gas cylinders. In this way economical and technical change researches has been done in order to construct on department to produce 200,000 compressive natural gas cylinders in a year during two sets.(shifts) According to the results of technical researches... 

    Synthesis, Characterization and Field Emission Study of Molybdenum Oxide (MoOx)Nanostructures

    , M.Sc. Thesis Sharif University of Technology Khademi, Ali (Author) ; Moshfegh, Alireza (Supervisor)
    Abstract
    Different molybdenum oxide nano/micro structure thin films were synthesized by thermal evaporation method under various growth conditions such as deposition time, temperature and evaporation source-substrate distance. Molybdenum oxide nanostructures grown on Si(100) such as nanowalls, nanostars and nanowires were characterized with scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), atomic force microscopy (AFM) and high resolution transmission electron microscopy (HRTEM). Shape and type of nanostructures were determined with SEM, AFM and HRTEM analysis. XPS analysis showed that the synthesized nanostructures contained Mo6+, Mo5+, Mo4+ and... 

    Identification and Abnormal Condition Detection of a Cement Rotary Kiln

    , M.Sc. Thesis Sharif University of Technology Sadeghian, Masoud (Author) ; Fatehi, Alireza (Supervisor)
    Abstract
    One of the most important parts of a cement factory is the cement rotary kiln which plays a key role in quality and quantity of produced cement. In this part, the physical exertion and bilateral movement of air and materials, together with chemical reactions take place. Thus, this system has immensely complex and nonlinear dynamic equations. These equations have not worked out yet. Only in exceptional case; however, a large number of the involved parameters were crossed out and an approximation model was presented instead. This issue caused many problems for designing a cement rotary kiln controller. In this thesis, we employed a nonlinear system identification method for identification,...