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mahboubi--sajad
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Optimal behavior of hot water heating coils at steady conditions
, Article 2008 ASME International Mechanical Engineering Congress and Exposition, IMECE 2008, Boston, MA, 31 October 2008 through 6 November 2008 ; Volume 10, Issue PART B , 2009 , Pages 1427-1432 ; 9780791848715 (ISBN) ; Saldi, M. H ; Sharif University of Technology
2009
Abstract
Hot water heating coils are key components in air conditioning systems undergo heat transfer. The most widely used exchangers (coils) take the form of fin and tube configuration in association with the application of air conditioning systems. In this research, thermodynamic modeling and mathematical optimization of hot water heating coils at steady conditions, approaching minimum energy consumption are achieved. The modeling procedure for heating coils is done based on the log mean temperature difference (LMTD) method. The objective function for optimization is pressure drop of air crossing coil per heating load of the system. This unction comprises all thermal and geometrical parameters of...
Multi-objective Optimization of a Megawatt Wind Turbine Blade Geometry Using an Evolutionary Algorithm
, M.Sc. Thesis Sharif University of Technology ; Darbandi, Masoud (Supervisor)
Abstract
Without optimization, it is impossible to reduce the cost of power generation from an efficient megawatt wind turbine. In this work, we present a multi-objective algorithm to optimize the megawatt blade geometry. In this algorithm, the mass of blade and the wind turbine annual energy production (AEP) are considered as the objective functions. The design variables are blade chord, blade twist, airfoil thickness, spar geometry and blade curvature distribution.The constraints are maximum allowable strain for the chosen materials, maximum tip deflection and maximum tip speed. For the internal geometry, we consider two spars and four panels. The blade element momentum method (BEM) is used for...
Developing an electro-thermal model to determine heat generation and thermal properties in a lithium-ion battery
, Article Journal of Thermal Analysis and Calorimetry ; Volume 147, Issue 21 , 2022 , Pages 12253-12267 ; 13886150 (ISSN) ; Jafari Gavzan, I ; Saidi, M. H ; Ahmadi, N ; Sharif University of Technology
Springer Science and Business Media B.V
2022
Abstract
Lithium-ion batteries should continuously be operated at the optimum temperature range (15∼40∘C) for the best performance. Surface temperature monitoring is critical for the safe and efficient operation of the battery. In this study, initially, the electrical parameters of the battery are determined by applying a second-order equivalent circuit model. This model then is integrated with a thermal model based on the temperature dependent behavior of the electrical parameters and the heat generated. The input parameters to the electro-thermal model include the current, the ambient fluid temperature and the output parameters include the terminal voltage, state of charge, cell core temperature...
State of charge estimation for lithium-ion batteries based on square root sigma point Kalman filter considering temperature variations
, Article IET Electrical Systems in Transportation ; Volume 12, Issue 3 , 2022 , Pages 165-180 ; 20429738 (ISSN) ; Jafari Gavzan, I ; Saidi, M. H ; Ahmadi, N ; Sharif University of Technology
John Wiley and Sons Inc
2022
Abstract
The battery management system (BMS) in electric vehicles monitors the state of charge (SOC) and state of health (SOH) of lithium-ion battery by controlling transient parameters such as voltage, current, and temperature prevents the battery from operating outside the optimal operating range. The main feature of the battery management system is the correct estimation of the SOC in the broad range of vehicle navigation. In this paper, to estimate real-time of SOC in lithium-ion batteries and overcome faults of Extended Kalman Filter (EKF), the Square-Root Sigma Point Kalman Filter is applied on the basis of numerical approximations rather than analytical methods of EKF. For this purpose, the...
Synthesis and Characterization of Grapheme Foams Fabricated by Chemical Vaporization Deposition
, M.Sc. Thesis Sharif University of Technology ; Akhavan, Omid (Supervisor) ; Azimirad, Rouhollah (Co-Advisor)
Abstract
The main purpose of this theses is to synthesize graphene by chemical vapor deposition (CVD) of a hydrocarbon gas such as methane on the nickel foam substrate and then to characterize this kind of graphene. Graphene is a single layer of carbon atoms, discovered in 2004, which has led mankind to new eras in all fields by its extraordinary features such as extra high electron mobility, high thermal conductivity, excellent mechanical strength, optical transparence and extra high specific surface. The advantage of this method compared to other methods is that the graphene generated has a better structural quality. Graphene foam firstly, because of the continuity of the foam structure, has better...
Adversarial Attack to Deep Learning Networks via Imperceptible Sparse Perturbation
, M.Sc. Thesis Sharif University of Technology ; Ghaemmaghami, Shahrokh (Supervisor) ; Marvasti, Farokh (Supervisor) ; Amini, Sajad (Co-Supervisor)
Abstract
Nowadays, methods based on deep learning networks are the most effective artificial in telligence methods. Although they have achieved success in various fields (such as machine vision and object recognition), practical and experimental cases show the fragility of deep learning networks against perturbations and unwanted changes of the input pattern. All these perturbations must be in a way that the main class of the perturbed input pattern can be rec ognized by human, but the network makes a mistake in recognizing its correct class. This thesis seeks a more accurate evaluation by designing adversarial attacks such that the main class of the adversarial pattern is detectable by human...
Intralesional immunotherapy compared to cryotherapy in the treatment of warts
, Article International Journal of Dermatology ; Volume 56, Issue 4 , 2017 , Pages 474-478 ; 00119059 (ISSN) ; Jabbari Azad, F ; Mahboubi Oskouei, Y ; Jafari, M ; Tehranian, S ; Alizadehsani, R ; Layegh, P ; Sharif University of Technology
Blackwell Publishing Ltd
2017
Abstract
Background: Warts are the most common clinical manifestation of the human papilloma-virus infection in the skin and mucous membranes. In spite of the various therapeutic modalities for nongenital skin warts, there is still no single method to be used as an approved treatment. In this study, we compared the efficacy of immunotherapy and cryotherapy on wart lesions. Methods: Sixty patients with verruca vulgaris and plantar warts were randomly divided into two groups. One group received intralesional injection of candida antigen repeated every 3 weeks until complete improvement of all warts or for a maximum of three sessions. The second group was treated by cryotherapy with liquid nitrogen for...
Dynamic response of metal foam FG porous cylindrical micro-shells due to moving loads with strain gradient size-dependency
, Article European Physical Journal Plus ; Volume 134, Issue 5 , 2019 ; 21905444 (ISSN) ; Forsat, M ; Barati, M. R ; Abdella, G. M ; Mohasel Afshari, B ; Hamouda, A. M. S ; Rabby, S ; Sharif University of Technology
Springer Verlag
2019
Abstract
The dynamic characteristics of functionally graded (FG) metal foam cylindrical micro-scale shells in contact with a moving load will be analyzed thorough this paper accounting for strain-gradient size-dependency. In the material structure of a metal foam, pores can diffuse uniformly or non-uniformly. Based upon Laplace transform, the dynamical governing equations of the first-order micro-shell model can be established in a new domain. In order to go back into the time domain, an inverse Laplace transform will be required. Thus, on can express the time response or dynamic deflection of the micro-shell under moving load. In the presented results, it is easy to see the prominence of...