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A new fuzzy multicriteria decision making method and its application in diversion of water
, Article Expert Systems with Applications ; Volume 37, Issue 12 , 2010 , Pages 8809-8813 ; 09574174 (ISSN) ; Shamsai, A ; Ahmady, N ; Sharif University of Technology
Abstract
Taking account of uncertainty in multicriteria decision making problems is crucial due to the fact that depending on how it is done, ranking of alternatives can be completely different. This paper utilizes linguistic values to evaluate the performance of qualitative criteria and proposes using appropriate shapes of fuzzy numbers to evaluate the performance of quantitative criteria for each problem with respect to its particular conditions. In addition, a process to determine the weights of criteria using fuzzy numbers, which considers their competition to gain greater weights and their influence on each other is described. A new fuzzy methodology is proposed to solve such a problem that...
δ M formalism: a new approach to cosmological perturbation theory in anisotropic inflation
, Article Journal of Cosmology and Astroparticle Physics ; Volume 2018, Issue 3 , 2018 ; 14757516 (ISSN) ; Ahmadi, N ; Abolhasani, A. A ; Sharif University of Technology
Institute of Physics Publishing
2018
Abstract
We study the evolution of the metric perturbations in a Bianchi background in the long-wavelength limit. By applying the gradient expansion to the equations of motion we exhibit a generalized "Separate Universe" approach to the cosmological perturbation theory. Having found this consistent separate universe picture, we introduce the δ M formalism for calculating the evolution of the linear tensor perturbations in anisotropic inflation models in almost the same way that the so-called δ N formula is applied to the super-horizon dynamics of the curvature perturbations. Similar to her twin formula, δ N, this new method can substantially reduce the amount of calculations related to the evolution...
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...
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...
Effect of Ca2+ additives on morphology, composition and corrosion resistant of Zn-12%Ni phosphate coating
, Article Journal of Materials Research and Technology ; Volume 5, Issue 4 , 2016 , Pages 327-332 ; 22387854 (ISSN) ; Hanaei, A ; Pakseresht, A. H ; Shahbazkhan, A ; Parvini Ahmadi, N ; Baniasadi, F ; Sharif University of Technology
Elsevier Editora Ltd
Abstract
The aim of this study is to investigate the effect of phosphate solution with Ca2+ additives on weight, surface morphology and electrochemical behavior of phosphated Zn-Ni film. In order to characterize structure and morphology of surface, X-ray diffraction (XRD) and scanning electron microscopy (SEM) were applied, respectively. Results showed that the main composition in produced coatings was hopeite Zn3(PO4)2·4H2O, which has high corrosion resistance. On one hand, in the presence of Ca2+ cations in solution, the weight of phosphate coating decreased, but on the other hand surface uniformity and corrosion resistance of the coating increased
Measurement of moisture and temperature profiles in different layers of soil
, Article 3rd International Foundation Congress and Equipment Expo 2018: Case Histories and Lessons Learned, IFCEE 2018, 5 March 2018 through 10 March 2018 ; Volume 2018-March, Issue GSP 298 , 2018 , Pages 266-278 ; 08950563 (ISSN) ; Ali, K ; Nazari, A ; Rezvani, S ; Khatami, A ; Ahmadi, N ; Deep Foundations Institute; International Association of Foundation Drilling; Pile Driving Contractors Association; The Geo-Institute (G-I) of the American Society of Civil Engineers (ASCE) ; Sharif University of Technology
American Society of Civil Engineers (ASCE)
2018
Abstract
Over past decades, extensive research has been performed on the measurement of land subsidence as a result of compaction of aquifer. This paper describes results from a new field-monitoring system to evaluate changes in matric suction and temperature profiles in soil layers over an extended time period. The monitoring system used in this study consists of inserting dielectric sensors into a 105 m borehole, drilled in a site in Ardabil Plain, The monitoring results from the site were used to calibrate predictions from HYDRUS-1D. The physical and hydraulic properties of the soil materials in different layers were obtained through performing some soil characteristics and filter paper tests...