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moosavi-larijani--arman
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The Impact of Entrepreneurial Attitude on Entrepreneurial Alertness and Investigating the Mediating Role of Curiosity
, M.Sc. Thesis Sharif University of Technology ; Tasavori, Misagh (Supervisor) ; Najmi, Manoochehr (Supervisor)
Abstract
The importance of a quick and authentic response in today's hectic business environment shows us the necessity of being alert. By understanding the value of alertness, we seek to find factors affecting it. In this article, we try to learn about new aspects of this structure. We expect that personality attributes and the way we look at the environment are influential in this matter. The amount of "curiosity" that is institutionalized in our personality and our "attitude" towards entrepreneurship has often been examined along with other concepts like mindfulness. However, the exact relationship between them has not been specifically analyzed. For this purpose, we started this research by...
Parallel hermite interpolation on the pyramid
, Article 22nd International Symposium on Computer and Information Sciences, ISCIS 2007, Ankara, 7 November 2007 through 9 November 2007 ; February , 2007 , Pages 403-407 ; 1424413648 (ISBN); 9781424413645 (ISBN) ; Sarbazi Azad, H ; Sharif University of Technology
2007
Abstract
The pyramid network is one of the most important interconnection topologies used as hardware architecture or software data structure. It has a combined tree-mesh structure making it suitable for solving many parallel problems and applications. This paper proposes a parallel algorithm for Hermite Interpolation on the Pyramid network which has at least N nodes. The proposed algorithm has 3 phases: initialization, main, and final. The algorithm is optimal with a time complexity of O(N) for an N-point interpolation. ©2007 IEEE
Experimental Study of Movement of Mercury Droplets in Micro Channel by Electromagnetic Force
, M.Sc. Thesis Sharif University of Technology ; Afshin, Hossein (Supervisor)
Abstract
As today's tremendous advance occurred in biotechnology and nanotechnology, the microfluidic devices made a new success that was not possible with the traditional equipments. It was useful in such a way that by using a microliter volume of that fluid, we could have the ability to use it in biologics, medicine, aerospace, cooling electronic systems and medical discovery. One of the main component of fluidic microsystems are micropumps in which they divide into two types. Reciprocating micropumps have been worked by stimulating electromagnetic micropumps which is based on Lorentz law. In this project, we try to investigate the impact of effective parameters in the movement of the mercury mass....
Design and Optimization of Helium Extraction and Liquefaction Cycle from Natural Gas by Direct Method
, Ph.D. Dissertation Sharif University of Technology ; Afshin, Hossein (Supervisor)
Abstract
Helium is known as a strategic material due to its unique properties and applications in the development of advanced industries. Currently, natural gas is the only source from which helium can be produced economically. The United States, Qatar, Algeria, and Russia have the largest share of helium production, respectively. In this research, the process of helium extraction from natural gas and its liquefaction, independent of LNG production based on helium in South Pars gas of Iran, which is the largest helium reservoir in the world, were designed and simulated.In the helium liquefaction section, the speed and accuracy of the process simulation were improved by developing a home code based on...
Design and implementation of an ADC-based real-time simulator along with an optimal selection of the switch model parameters
, Article Electrical Engineering ; Volume 103, Issue 5 , 2021 , Pages 2315-2325 ; 09487921 (ISSN) ; Zolghadri, M. R ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
The method for modeling switching converters plays a key role in real-time simulators. Associate discrete circuit (ADC) modeling technique is a commonly used method for modeling the switching converter. However, the optimal selection of the ADC-based switch model parameters has great importance in the accuracy of the real-time simulator. In this paper, the design of a real-time simulator for a switching power converter has been done, in which a novel method for detecting optimum values of the switch model parameters has been expressed. Particle swarm optimization (PSO) algorithm is used to find these optimum values using state-space analysis of the modeled circuit in the z-domain. The...
Simulation and performance improvement of cryogenic distillation column, using enhanced predictive Peng–Robinson equation of state
, Article Fluid Phase Equilibria ; Volume 489 , 2019 , Pages 117-130 ; 03783812 (ISSN) ; Bayat, M ; Afshin, H ; Sharif University of Technology
Elsevier B.V
2019
Abstract
In this study, a cryogenic distillation column has been designed and simulated via a computer code based on the theta method of convergence. The required thermodynamic properties are determined from the enhanced predictive Peng-Robinson (E-PPR 78) equation of state which has a good accuracy in predicting the corresponding thermodynamic properties of natural gas components. The combined code of distillation column/equation of state has been verified with that of another study. In the present study, the results are achieved by the constant molar over-flow and inclusion of energy equations assumptions. In order to have more accuracy in the results, the energy equations were considered in the...
Investigation of effective parameters on the performance of the helium liquefaction cycle
, Article International Journal of Heat and Technology ; Volume 37, Issue 4 , 2019 , Pages 1009-1018 ; 03928764 (ISSN) ; Eslami, M ; Afshin, H ; Sharif University of Technology
International Information and Engineering Technology Association
2019
Abstract
Due to its unique properties, helium has wide application in different industries and scientific fields, which has turned it into a strategic material. Helium liquefaction plants include wide temperature range from 300 k to 4.2 k, so these plants have high energy consumption. A lot of studies have done to optimize the operation of these cycles. In this research, an exergy analysis is performed for a liquid helium production plant. The optimal performance of 3 and 4 stage cycles is extracted using parametric study and the results are compared with those of Collins dual-expander cycle. The results show that by increasing the number of cooling stages, not only the compressor optimum discharge...
Simulation of hybrid reo connectors
, Article 3rd CSI/CPSSI International Symposium on Real-Time and Embedded Systems and Technologies, RTEST 2020, 10 June 2020 through 11 June 2020 ; 2020 ; Farhadi, A ; Arbab, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
The prevalence of complex Cyber-Physical Systems (CPS) as an increasingly ubiquitous technology, necessitates the incorporation of component based and compositional design methods for the development and deployment of such systems. In this paper, we introduce a hybrid coordination framework to specify CPSs with components and use the resulting models to simulate, validate and verify those systems, using UPPAAL statistical model checker (SMC). We use SMC because with a level of uncertainty and unpredictability (e.g., the physical environment with which a CPS interacts), simulation-based verification approaches, where properties are guaranteed with a degree of confidence, produce more...
Investigation of effective parameters on the performance of the helium liquefaction cycle
, Article International Journal of Heat and Technology ; Volume 37, Issue 4 , 2019 , Pages 1009-1018 ; 03928764 (ISSN) ; Eslami, M ; Afshin, H ; Sharif University of Technology
International Information and Engineering Technology Association
2019
Abstract
Due to its unique properties, helium has wide application in different industries and scientific fields, which has turned it into a strategic material. Helium liquefaction plants include wide temperature range from 300 k to 4.2 k, so these plants have high energy consumption. A lot of studies have done to optimize the operation of these cycles. In this research, an exergy analysis is performed for a liquid helium production plant. The optimal performance of 3 and 4 stage cycles is extracted using parametric study and the results are compared with those of Collins dual-expander cycle. The results show that by increasing the number of cooling stages, not only the compressor optimum discharge...
Design and Implementation Real-Time Simulator for CHB Converter using FPGA
, M.Sc. Thesis Sharif University of Technology ; Zolghadri, Mohammad Reza (Supervisor)
Abstract
With development of power electronic science and with the existence of different power electronic converters in this field, the need for improving their operation and the fault detection methods of these converters, the need for simulation and test of them is strong felt. However, experimental constrain such as damage risks, reliability, costs, and so on obviate the need for making the converter and the need for testing it and its controller. Accordingly, we do the testing on a special platform for Real-Time simulation.Control/protection platform needs to be tested and its functionality should be verified prior to installation and commissioning.Testing in theReal-Time simulator environment...
Design and implementation of an FPGA-based real-time simulator for H-bridge converter
, Article 7th Power Electronics, Drive Systems and Technologies Conference, PEDSTC 2016, 16 February 2016 through 18 February 2016 ; 2016 , Pages 504-510 ; 9781509003754 (ISBN) ; Zolghadri, M. R ; Shahbazi, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
This paper presents a methodology for implementing of the mathematical model of H-Bridge converter in an FPGA-based Real-Time simulator. Furthermore, it introduces a new method for choosing parameters of the Associate Discrete Circuit (ADC) model of semiconductor switches. The ADC-based model allows obtaining a fixed topology irrespective of switches states for the power electronic converters in the digital simulation. Backward-Euler based discretized state space matrix (SSM) of the circuit used for ADC parameter. Choosing appropriate switch parameter is based on 1) reducing the distance of SSM eigenvalues from origin in z-Plane to reduce settling-Time of system response; and 2) reducing the...
Investigating and Estimating the Relation between Import tariff Rate and Smuggling in Iran
, M.Sc. Thesis Sharif University of Technology ; Vesal, Mohammad (Supervisor) ; Memarnezhad, Abbas (Co-Advisor)
Abstract
Governments use tariff and non-tariff import barriers for several reasons including protecting national industries, tax income and or checking the quality of imported products. These barriers motivate importers to make a profit through smuggling. This study focuses on “import tariff rate” as a main motivation for smuggling and tries to estimate the elasticity of smuggling with respect to tariff rates. Iran trade flow data and tariff rates are collected from Trademap, WITS, Iran’s customs administration and Iran’s Trade Development Organization. By observing reported exports to Iran from main trade partners together with reported imports to Iran we construct a proxy for the amount of...
Coarsening dynamics of dewetting nanodroplets on chemically patterned substrates
, Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 86, Issue 1 , July , 2012 ; 15393755 (ISSN) ; Sharif University of Technology
2012
Abstract
Mesoscopic hydrodynamic equations are solved to investigate coarsening dynamics of two interacting nanodroplets on chemically patterned substrates. The effects of different parameters such as the surface chemical pattern, the slip length, the profile of the disjoining pressure, the size of the droplets, and the contact angles on the coarsening are studied. Our results reveal that the presence of a chemical heterogeneity can enhance or weaken the coarsening dynamics depending on the pattern type and positions of the droplets on the substrate. Also increasing the contact angles to values larger than a critical value may qualitatively change the coarsening process, and the profile of the...
Comparing half-metallic, MOKE, and thermoelectric behavior of the CrTiZ (Z = As, P) half-Heuslers: A DFT study
, Article Materials Research Express ; Volume 8, Issue 4 , 2021 ; 20531591 (ISSN) ; Zelati, A ; Boochani, A ; Arman, A ; Mirzaei, S ; Sharif University of Technology
IOP Publishing Ltd
2021
Abstract
Structural, half-metallic, magneto-optic, and thermoelectric properties of CrTiZ (Z = As, P) half-Heusleres compounds are investigated based on density functional theory. These compounds have mechanical stability in the ferromagnetic state with a high bulk modulus. They are often half-metallic with a large and integer magnetic moment and are very attractive in spintronics, magneto-optics applications. The magnetic moments of CrTiAs and CrTiP were 2.9865 μB and 3.00 μB, respectively, which were attributed to their ferromagnetic phase. Additionally, the positive sign of the phonon branches indicates the dynamic stability of these compounds. Applying both GGA and mBJ approximations, CrTiAs and...
The Effect of Rudder Angle on Ship’s Fuel Consumption
, M.Sc. Thesis Sharif University of Technology ; Khorasanchi, Mahdi (Supervisor) ; Zare, Arman (Co-Supervisor)
Abstract
The aim of this research is to investigate the effect of speed and direction of current on ship fuel consumption. A KCS benchmark model has been numerically studied in calm water and fourteen current and wind conditions with the same speed and different directions to determine how the ship performance is dependent on flow conditions. The model has been simulated in an artificial basin propelled by a single right-handed propeller via a CFD commercial code. Numerical results revealed a linear relationship between the deviation of current and wind from head-sea or following-sea conditions and the rudder angle. The head-sea and following-sea currents and winds increased and decreased the lateral...
Visible light photo-induced antibacterial activity of CNT-doped TiO 2 thin films with various CNT contents
, Article Journal of Materials Chemistry ; Volume 20, Issue 35 , Jun , 2010 , Pages 7386-7392 ; 09599428 (ISSN) ; Azimirad, R ; Safa, S ; Larijani, M. M ; Sharif University of Technology
2010
Abstract
Carbon nanotube (CNT)-doped TiO2 thin films with various CNT contents were synthesized by sol-gel method for visible light photoinactivation of Escherichia coli bacteria. Post annealing of the CNT-doped TiO2 thin films at 450 °C resulted in anatase TiO2 and formation of Ti-C and Ti-O-C carbonaceous bonds in the film. By increasing the CNT content, the thin films could further inactivate the bacteria in the dark. Meanwhile, as the CNT content increased from zero to 40 wt% the effective optical band gap energy of the CNT-doped TiO2 thin films annealed at 450 °C decreased from 3.2-3.3 to less than ∼2.8 eV providing light absorption in the visible region. Concerning this, visible light...
Structural and corrosion characterization of hydroxyapatite/zirconium nitride-coated AZ91 magnesium alloy by ion beam sputtering
, Article Applied Surface Science ; Volume 401 , 2017 , Pages 172-180 ; 01694332 (ISSN) ; Afshar, A ; Mojtahedzadeh Larijani, M ; Yousefpour, M ; Sharif University of Technology
2017
Abstract
The adhesion of hydroxyapatite (HA) as a coating for the AZ91 magnesium alloy substrate can be improved by using the sputtering method and an intermediate layer, such as ZrN. In this study, HA coatings were applied on ZrN intermediate layers at a temperature of 300 °C for 180, 240, 300, 360, and 420 min by ion beam sputtering. A profilometer device was used to study the HA coating thickness, which changed from 2 μm for the 180-min deposition to 4.7 μm for 420-min deposition. The grazing incidence X-ray diffraction analysis method and the Williamson–Hall analysis were used for structural investigation. As the deposition time increased, the crystalline size increased from 50 nm to 690 nm....
The Real Effect of Banks’ Money Creation Ability in a New Keynesian Framework
, M.Sc. Thesis Sharif University of Technology ; Madanizadeh, Ali (Supervisor) ; Mahmoodzadeh, Amineh (Supervisor)
Abstract
In much of the financial economics literature, banks are modeled as financial intermediaries that transfer household deposits to loan applicants. In these models, deposits are obtained from the accumulation of real amounts (household savings). In addition to this, another approach describes banks not as intermediaries of loanable funds, but as money-creators who do not need to accumulate deposit resources to lend. In this study, by modeling the money-creation behavior of the banking network, we try to answer the question that if the bank can create credit and purchasing power for the firm based on its future income, how will the general variables of the economy, including consumption and...
Performance analysis of the lithium-ion battery RC equivalent circuit model using EPA drive cycles
, Article 13th Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2022, 1 February 2022 through 3 February 2022 ; 2022 , Pages 393-397 ; 9781665420433 (ISBN) ; Zolghadri, M ; Kia, S. H ; El Hajjaji, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
This paper compares the dynamic and static models of a Lithium-ion battery pack with its electrochemical model as energy storage of an electric vehicle according to the environmental protection agency drive cycles. The dynamic model or the RC equivalent circuit includes a voltage source and double parallel resistor and capacitor networks which are connected in series. The static model includes a voltage source and resistors. Given drive cycles, these models are compared in terms of the battery voltage, state-of-charge, and power loss in an electric vehicle in MapleSim software. Although the state-of-charge and power loss of both models are identical to each other, actually the terminal...
Evaluation of the topographical surface changes of silicon wafers after annealing and plasma cleaning
, Article Silicon ; Volume 12, Issue 11 , 2020 , Pages 2563-2570 ; Ţălu, Ş ; Dallaev, R ; Arman, A ; Sobola, D ; Salerno, M ; Sharif University of Technology
Springer Science+Business Media B.V
2020
Abstract
Purpose: The morphological stability of silicon single crystal wafers was investigated, after performing cleaning surface treatments based on moderate temperature annealing and plasma sputtering. Methods: The wafer surfaces were measured by Tapping mode atomic force microscopy in air, before and after the different treatments. The 3D images were segmented by watershed algorithm identifying the local peaks, and the stereometric parameters were extracted thereof. The analysis of variance allowed to better assess the statistically significant differences. Results: All the resulting quantities were critically discussed. It appeared that the different cleaning treatments affected differently the...