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rahimpour--amir
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Li-ion Battery Thermal Management System Utilizing Phase Change Material and Intermediate Boiling Fluid
, M.Sc. Thesis Sharif University of Technology ; Shafii, Mohammad Behshad (Supervisor) ; Ghahremani, Amir Reza (Supervisor)
Abstract
Recent advancements in technology and the growing human demand for energy have driven researchers towards developing new methods for energy storage and transfer. Lithium-ion batteries are among the most crucial technologies used in this field, requiring heat dissipation for proper operation. When using these batteries, in addition to keeping the maximum temperature within an acceptable range, the maximum temperature difference is also important and must be considered. Given the suitable ability of phase change materials (PCMs) in controlling temperature uniformity, many researchers have explored hybrid battery cooling systems that combine PCMs with other cooling methods. In the current...
Distributed Sparse Signal Recovery
, M.Sc. Thesis Sharif University of Technology ; Marvasti, Farrokh (Supervisor)
Abstract
Sensor Networks are set of devices which are distributed throughout an environment and are connected to each other, usually wirelessly, to collect environmental information including temperature, aire pressure, moist, pollution and physiological functions of the human body. Each device consists of a microprocessor, converter and power supply, transmitter and a receiver. In this study we intend to investigate such setup and the measured signals assuming they are sparse. A sparse signal is a discrete time signal most of indices of which are equal to zero. With this assumption at hand, we will be able to reduce the sampling rate and take advantage of sparse signal processing techniques. This...
A probabilistic neural network classifier-based method for transformer winding fault identification through its transfer function measurement
, Article International Transactions on Electrical Energy Systems ; Volume 23, Issue 3 , 2013 , Pages 392-404 ; 20507038 (ISSN) ; Vakilian, M ; Rahimpour, E ; Sharif University of Technology
2013
Abstract
In this paper, a new method is introduced for identification of transformer winding fault through transfer function analysis. For this analysis, vector fitting and probabilistic neural network are used. The results of transfer functions estimation through vector fitting are employed for training of neural network, and consequently, probabilistic neural network is used for classification of faults. The required data for fault type identification are obtained by measurements on two groups of transformers (one is a classic 20 kV transformer, and the other is a model transformer) under intact condition and under different fault conditions (axial displacement, radial deformation, disc space...
Comparison of transfer functions using estimated rational functions to detect winding mechanical faults in transformers
, Article Archives of Electrical Engineering ; Volume 61, Issue 1 , 2012 , Pages 85-99 ; 00040746 (ISSN) ; Vakilian, M ; Rahimpour, E ; Sharif University of Technology
2012
Abstract
As it is found in the related published literatures, the transfer function (TF) evaluation method is the most feasible method for detection of winding mechanical faults in transformers. Therefore, investigation of an accurate method for evaluation of the TFs is very important. This paper presents three new indices to compare the transformer TFs and consequently to detect the winding mechanical faults. These indices are based on estimated rational functions. To develop the method, the necessary measurements are carried out on a 1.3 MVA transformer winding, under intact condition, as well as different fault conditions (axial displacement of winding). The obtained results demonstrate the high...
Transformer winding faults classification based on transfer function analysis by support vector machine
, Article IET Electric Power Applications ; Volume 6, Issue 5 , 2012 , Pages 268-276 ; 17518660 (ISSN) ; Vakilian, M ; Rahimpour, E ; Sharif University of Technology
2012
Abstract
This study presents an intelligent fault classification method for identification of transformer winding fault through transfer function (TF) analysis. For this analysis support vector machine (SVM) is used. The required data for training and testing of SVM are obtained by measurement on two groups of transformers (one is a classic 20 kV transformer and the other is a model transformer) under intact condition and under different fault conditions (axial displacement, radial deformation, disc space variation and short circuit of winding). Two different features extracted from the measured TFs are then used as the inputs to SVM classifier for fault classification. The accuracy of proposed...
A new method for detection and evaluation of winding mechanical faults in transformer through transfer function measurements
, Article Advances in Electrical and Computer Engineering ; Volume 11, Issue 2 , 2011 , Pages 23-30 ; 15827445 (ISSN) ; Vakilian, M ; Rahimpour, E ; Sharif University of Technology
2011
Abstract
Transfer function (TF) is an acknowledged method for power transformer mechanical faults detection. However the past published works mostly discovered how to specify the faults levels and paid less attention to detection of the type of faults using comparison of TFs. whereas, it seems important for most of the applications to specify the type of fault without opening the unit. This paper presents a new method based on vector fitting (VF) to compare the TFs and specify the type, level and location of the fault. For development of the method, and its verification the required measurements are carried out on four model transformers; under intact condition, and under different fault conditions...
The effect of seasonal variation in precipitation and evapotranspiration on the transient travel time distributions
, Article Advances in Water Resources ; Volume 142 , 2020 ; Danesh Yazdi, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Precipitation (P), plant water use, and evaporation from the soil surface control the travel time of streamflow (Q) and evapotranspiration (ET) in a complex way. However, the impact of soil moisture and energy availability on the travel time distribution (TTD) of evaporated and transpired waters are yet less understood. In this study, we investigate how the seasonal variability of P and ET in terms of phase shift and rate influences the temporal dynamics of TTDs. To this end, we choose four contrasting climate types described as in-phase P and ET, out-of-phase P and ET, year-round constant P with seasonal ET, and year-round constant ET with seasonal P. We use a physically-based hydrological...
Transformer winding diagnosis using comparison of transfer function coefficients
, Article ECTI-CON 2011 - 8th Electrical Engineering/ Electronics, Computer, Telecommunications and Information Technology (ECTI) Association of Thailand - Conference 2011, 17 May 2011 through 19 May 2011, Khon Kaen ; 2011 , Pages 681-683 ; 9781457704246 (ISBN) ; Vakilian, M ; Rahimpour, E ; Azizian, D ; Sharif University of Technology
2011
Abstract
In this work, a new model of transformer winding is developed. The components in the model are determined by the geometric and electric data of the winding. Under different degrees of axial displacement and radial deformation in the winding, circuit parameters in the model will be changed and thus the character of the circuit will be influenced. After acquiring the model parameters in the intact and faulted cases, transfer function coefficients derived in model from nodal analysis. Then using introduce the new index based on coefficients we can specify the type and extent of penetration of the fault in the winding. Results presented demonstrate the potential of this method
Theoretical and experimental investigation of transformer winding fault detection using comparison of transfer function coefficients
, Article Transactions on Electrical Engineering, Electronics, and Communications ; Volume 10, Issue 1 , 2012 , Pages 10-16 ; 16859545 (ISSN) ; Vakilian, M ; Rahimpour, E ; Azizian, D ; Sharif University of Technology
2012
Abstract
In this work, a new model of transformer winding is developed. The components in the model are determined by the geometric and electric data of the winding (detailed model) and using experimental data based on genetic algorithm. Under different degrees of axial displacement and radial deformation in the winding, the circuit parameters of the model will change and thus the equivalent circuit characteristics will be influenced. After acquiring the model parameters in the intact and faulted cases, transfer function coefficients are derived in model using nodal analysis. Subsequently, introducing a new index based on these coefficients, the type and extent of penetration of the fault in the...
A general model for I/O system theory, Proceedings of AIMC31 [electronic resource]
, Article Iranian Journal of Fuzzy Systems ; 2006, Volume 3, Issue 2, Page 1-19 ; Hashem, Amir ; Sharif University of TechnologyApplying ultrasonic fields to separate water contained in medium-gravity crude oil emulsions and determining crude oil adhesion coefficients
, Article Ultrasonics Sonochemistry ; Volume 70 , 2021 ; 13504177 (ISSN) ; Wood, D. A ; Jokar, S. M ; Rahimpour, M. R ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Separating produced water is a key part of production processing for most crude oils. It is required for quality reasons, and to avoid unnecessary transportation costs and prevent pipework corrosion rates caused by soluble salts present in the water. A complicating factor is that water is often present in crude oil in the form of emulsions. Experiments were performed to evaluate the performance of ultrasonic fields in demulsifying crude oil emulsions using novel pipe-form equipment. A horn-type piezoelectric ultrasonic transducer with a frequency of 20 kHz and power ranging from 80 W to 1000 W was used for experimental purposes. The influences of the intensity of ultrasonic fields,...
Corrigendum to “Applying ultrasonic fields to separate water contained in medium-gravity emulsions and determining adhesion coefficients” [Ultrasonics Sonochemistry 70 (2021) 105303] (Ultrasonics Sonochemistry (2021) 70, (S1350417720307112), (10.1016/j.ultsonch.2020.105303))
, Article Ultrasonics Sonochemistry ; Volume 72 , 2021 ; 13504177 (ISSN) ; Wood, D. A ; Jokar, S. M ; Rahimpour, M. R ; Sharif University of Technology
Elsevier B.V
2021
Abstract
In the original publication, The title of the paper is incorrect. Title should be state “Applying ultrasonic fields to separate water contained in medium-gravity emulsions and determining adhesion coefficients”. The authors would like to apologise for any inconvenience caused. © 2020 Elsevier B.V
Kinetic Study of Partial Oxidation of Methane in Non-Catalytic Porous Media
, M.Sc. Thesis Sharif University of Technology ; Fotovat, Farzam (Supervisor) ; Soltanieh, Mohammad (Supervisor)
Abstract
Partial oxidation of methane (POX) is one of the most common processes to produce synthesis gas. In this study the kinetics of this process is examined and some reduced mechanisms are introduced to model it in this study. The experimental data from Research Institute of Petroleum Industry are used as reference experimental data. Inlets of this reactor are oxygen and methane with equivalence ratio between 2.53 and 2.9. Moreover, the experimental results of previous studies with the air as the oxidant in equivalence ration between 2.4 and 2.6 are used as basis for comparison of simulation results. During the first step, partial oxidation of methane in non-catalytic porous media is simulated by...
Experimental and theoretical study of crude oil pretreatment using low-frequency ultrasonic waves
, Article Ultrasonics Sonochemistry ; Volume 48 , 2018 , Pages 383-395 ; 13504177 (ISSN) ; Sadatshojaie, A ; Parvasi, P ; Rahimpour, M. R ; Naserimojarad, M. M ; Sharif University of Technology
2018
Abstract
In this work, an ultrasound experimental setup was designed to investigate the feasibility of using low-frequency ultrasonic waves as a substitute to reduce the consumption of chemical demulsifiers in the pretreatment of crude oil. The experiments were planned to study the effects of irradiation time, ultrasonic field intensity and initial water content on the efficiency of separation. The results of experiments showed that by selecting a proper irradiation time and field intensity, it is possible to decrease the usage of demulsifiers by 50%. Moreover, a population balance model was proposed to explicate the experimental data. A hybrid coalescence model was developed to determine the...
Development of porous nanocomposite membranes for gas separation by identifying the effective fabrication parameters with Plackett–Burman experimental design
, Article Journal of Porous Materials ; Volume 23, Issue 5 , 2016 , Pages 1279-1295 ; 13802224 (ISSN) ; Safekordi, A ; Rashidzadeh, M ; Khanbabaei, G ; Akbari Anari, R ; Rahimpour, M ; Sharif University of Technology
Springer New York LLC
2016
Abstract
In this research, Plackett–Burman experimental design was used as a screening method to investigate seven processing factors in the preparation of new polyethersulfone based porous nanocomposite membrane. Polymer concentration, nanoparticle type, nanoparticle concentration, solvent type, solution mixing time, evaporation time, and annealing temperature are variables that were evaluated to fabricate mixed matrix membranes using the evaporation phase inversion method for gas separation. According to obtained results, polymer concentration, nanoparticle concentration, solution mixing time, and evaporation time processing factors had significant effects on gas permeation. In addition, the...
Experimental investigation of a multi-effect active solar still: The effect of the number of stages
, Article Applied Energy ; Volume 137 , 2015 , Pages 46-55 ; 03062619 (ISSN) ; Feilizadeh, M ; Jafarpur, K ; Feilizadeh, M ; Rahimpour, M. R ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
In this work, the effect of the number of stages on the productivity of a multi-effect active solar still was experimentally investigated for the first time. Moreover, system performances in continuous and non-continuous modes were compared. For this purpose, indoor experiments were conducted on 4 similar solar still devices with different stages (1-4 stages) in order to accurately control the environmental conditions. In addition, water production was hourly measured during the whole 24-h experiment. The results show that with increased number of stages, distillate production can be predicted with a quadratic function. Moreover, adding a maximum of 6 and 10 additional stages can...
Erratum: A computer model for evaluating the osteotomy parameters of Chiari pelvic osteotomy (International Orthopaedics (SICOT) DOI: 10.1007/s00264-009- 0769-2)
, Article International Orthopaedics ; Volume 34, Issue 4 , 2010 , Pages 619- ; 03412695 (ISSN) ; Gouran Savadkoohi, D ; Ghadirpour, A ; Rahimpour, S ; Azghani, M ; Farahmand, F ; Sharif University of Technology
2010
A novel nanocomposite with superior antibacterial activity: a silver-based metal organic framework embellished with graphene oxide
, Article Advanced Materials Interfaces ; Volume 5, Issue 11 , 3 April , 2018 ; 21967350 (ISSN) ; Arabi Shamsabadi, A ; Sharifian Gh, M ; Rahimpour, A ; Soroush, M ; Sharif University of Technology
Wiley-VCH Verlag
2018
Abstract
Silver-based nanomaterials have attracted considerable attention due to their antimicrobial activities. In this work, a silver (Ag)-based metal organic framework (Ag-MOF) is embellished with graphene-oxide (GO), leading to the fabrication of a novel Ag-based nanocomposite (GO-Ag-MOF) whose biocidal activity is higher than those of Ag-MOF and GO nanomaterials. The nanocomposite is characterized using X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscope, Fourier transform infrared spectra, ultraviolet−visible absorption spectra, X-ray powder diffraction, dynamic light scattering, and nitrogen gas adsorption/desorption. The characterization shows that...
Synthesis and Investigation of Properties of (K,Na)NbO3-Based Piezoelectrics
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor) ; Faghihi Sani, Mohammad Ali (Supervisor)
Abstract
The fabrication of potassium sodium niobate piezoceramic with oriented microstructure and study of its piezoelectric properties is one of the main objectives of the present study. For this purpose, first the raw materials were synthesized. solid state reaction and topochemical reaction were used for the synthesis of potassium sodium niobate and sodium niobate respectively. The X-ray diffraction results determined that the powder synthesized by the solid state method in the binary system KNbO3-NaNbO3 is closer to the morphotropic phase boundary compared to the powder synthesized in the ternary system Na2CO3-K2CO3-Nb2O5. Particles morphology also includes coarse cubic shape and small equiaxed...
Experimental and Numerical Study of Spray Combustion under Hot-diluted Conditions
, M.Sc. Thesis Sharif University of Technology ; Mardani, Amir (Supervisor)
Abstract
In this thesis, combustion of liquid fuel spray under the condition of hot and diluted oxidizer, has been investigated. To this end, a novel type laboratory-scale test rig was designed to study the physics governing the MILD-Spray combustion conditions with an applied approach. The underlined test rig eliminates the operational problems of its predecessor test stands and is used for a heavier fuel with much more complex chemical composition (kerosene). The test section is axially symmetrical, in which the fuel is injected by a pressure-swirl atomizer in the direction of hot and diluted co-flowing air. With the use of the aforesaid test rig, the effect of variables such as oxygen...