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karami-basiri--mohammad
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Fabrication and Evaluation of Catalytic Microreactors to Verify the Conversion of Ethyl Mercaptan
, M.Sc. Thesis Sharif University of Technology ; Kazemeini, Mohammad (Supervisor)
Abstract
Sulfur compounds are largely an impurity in fossil fuels such as natural gas, crude oil and coal. In natural gas, the main sulfur compounds are hydrogen sulfide (H2S), carbonyl sulfide (COS),and C1-C3 mercaptans.Commercial methods for removing these compounds require the introduction of additional reactive substances (O2, H2, Olefins, NaOH, etc.), which often results in the production of other pollutants. Microfluid is a branch of science and technology that involves studying the behavior of fluid, the use of fluid and the manufacture of equipment or systems that are carried out in micro-channels.The dimensions of these canals are about ten to several hundred micrometers, and high of...
Design of Fractional Order Controllers for Preservation of Phase Margin in the Presence of Parametric Uncertainties
, M.Sc. Thesis Sharif University of Technology ; Tavazoei, Mohammad Saleh (Supervisor)
Abstract
In the present thesis, first of all we consider a particular class of fractional order plants which have uncertainty in their time constant.In order to make the closed loop system robust against variations of the aforementioned parameter, a robust fractional order controller will be designed and the corresponding tuning rule will be expressed. By using the proposed controller, phase margin of the system will be preserved on a desired value for any value of the uncertain parameter and also gain crossover frequency of the system, in the nominal case, will be adjustable.Also another class of fractional order system will be considered. For these systems, the problem is the same as the former...
Design of a Thermoacoustic Refrigerator Based on the Airport Noise Absorption
, M.Sc. Thesis Sharif University of Technology ; Soltani, Mohammad Reza (Supervisor)
Abstract
In the last few decades, the consumption of fossil fuels and its increasing worldwide price on one hand, and the severity of global warming on the other hand have led researchers and engineers to invent and expand new cooling technologies. Cooling has the largest portion of energy consumption of households during the hot season of a year. In addition to high energy consumption, the common cooling systems utilize gases which are harmful for environment. Thermoacoustics is a new and recent technology which has arised from combination of acoustics and thermodynamics. In Iran, research in this new field was pioneered by Ghorbanian in Department of Aerospace Engineering at Sharif University of...
Analyzing the Trade-Off Between Performance and Computational Cost in Encrypted Control Systems
, M.Sc. Thesis Sharif University of Technology ; Tavazoei, Mohammad Saleh (Supervisor)
Abstract
Cloud control systems have garnered significant attention due to the many advantages of cloud computing, such as the ability to store and process large amounts of data efficiently. However, transferring data over public networks introduces several challenges for control systems. One major concern is the system's vulnerability to eavesdropping and security threats. Additionally, the computational demands of cloud-based controllers can result in increased system delays. This thesis addresses these challenges by integrating encryption methods with control theory. It focuses on mitigating the computational overhead introduced by encrypted networks and proposes two innovative solutions to tackle...
Designing a Multi-Model Sliding Mode Controller for a Magnetic Levitation System
, M.Sc. Thesis Sharif University of Technology ; Haeri, Mohammad (Supervisor)
Abstract
In this project a complete simulator for a two-winding, 25cm air gap Maglev system by considering the pratical constaritns, position and velocity observer and the current sensor dynamics was derived. In order to control the ball in any desired position a twisting sliding mode controller was designed as the basic controller in the rest of project. The designed controller can not transfer the ball in far trajectory. In first step we modify that to reach a better performance by changing the value of current, passing through the coils in steady state. In the second step, the far trajectories are divided to a finite number of sub-trajectory such that the ball can pass these sub-trajectory by...
Grammaticality Judgment Tests and Magnitude Estimation
, M.Sc. Thesis Sharif University of Technology ; Salehi, Mohammad (Supervisor)
Abstract
The present study aims at examining interval scaling and magnitude estimation in grammaticality judgment tests in terms of reliability and validity. It also explores the probable impact of response formats on the participants’ performance. 30 Engineering students at Sharif university of Technology participated in this research. The instrument of the research is a grammaticality judgment test developed by Ellis (1990).Two computer-based programs were made in order to assess the two mentioned response formats in grammaticality judgment test. At the first phase of the study, the participants responded to the interval format and after an interval of one month, they attempted the second response...
Optical Communication Impairments Mitigation Using Interpretable Machine Learning
, M.Sc. Thesis Sharif University of Technology ; Pakravan, Mohammad Reza (Supervisor) ; Hadi, Mohammad (Co-Supervisor)
Abstract
Optical impairments, as a challenging obstacle in optical communication systems, have been under deep attention of optical engineers in recent years. These impairments can be divided into two categories of linear and nonlinear impairments. Dispersion is a significant linear impairment leads to broadening of the optical signal and interference between transmitted symbols during detection. Nonlinear impairments such as cross-phase modulation (XPM) and self-phase modulation (SPM) also distort the transmitted signal through the fiber, causing interference at the receiver and degrading the system's performance. An appropriate solution for compensating optical fiber impairments is to utilize...
Determination of Hydrazine and Phenylhydrazine Based on Formation of Gold Nanoparticles Stabilized with Non-ionic Surfactants
, M.Sc. Thesis Sharif University of Technology ; Hormozi Nezhad, Mohammad Reza (Supervisor)
Abstract
A simple and effective procedure is proposed for colorimetric detection of hydrazine and phenylhydrazine. It was found that the reduction of AuCl4- to gold nanoparticles (Au-NPs) by these compunds in the presence of Tween-20 as a stabilizing agent produced very intense surface plasmon resonance peak of Au-NPs. The plasmon absorbance of the Au-NPs allows the quantitative spectrophotometric detection of the hydrazine and phenylhydrazine. The calibration curves derived from the changes in absorbance at λ = 530 and λ = 550 nm for hydrazine and phenylhydrazine, respectively were linear with concentration of hydrazine and phenylhydrazine in the range of 1.0×10-6- 2.0×10-4 M, 5×10-6 - 4×10-4 M,...
Separation of Olefins from Paraffins Using Nanocomposite Polymeric Membranes
, M.Sc. Thesis Sharif University of Technology ; Soltanieh, Mohammad (Supervisor) ; Goodarznia, Iraj (Supervisor)
Abstract
In this study, fabrication of polymeric nanocomposite membranes for separation of olefins from paraffins was investigated. Silver nanoparticles were prepared by Polyol chemical reduction method. At first, dense ethylcellulose and ethylcellulose-silver nanoparticles membranes were fabricated by solvent-evaporation method. Then Asymmetric EC and EC-silver nanoparticle nanocomposite membranes were fabricated by dry/wet phase inversion method as a means to improve flux rates and olefin selectivity in olefin/paraffin separations. The membranes properties and The Effects of incorporating nanoparticles in polymer matrix in low concentration on gas permeability and membranes morphology were...
Evaluating the Effect of Marketing Measures on the Performance of Companies Listed on the Iranian Stock Exchange
, M.Sc. Thesis Sharif University of Technology ; Karami, Naser (Supervisor)
Abstract
The issue of spending companies' resources on marketing measures, due to the lack of a proper mechanism to explain the impact and role of these measures has always been one of the most challenging problems for many stakeholders of companies, especially managers. In this study, we have tried to explain the relationship between marketing costs and credit policies with the financial performance of companies by examining the information published by companies listed on the Tehran Stock Exchange. In this study, the required information was collected from the sources of valid tools and then, using statistical methods, regression models that express the relationship between variables were...
Fabrication of Nuclear Fuel Pellet With a Mixture of Micro and Nano UO2 Powders And Investigation of Its Physical and Mechanical Properties
, M.Sc. Thesis Sharif University of Technology ; Otukesh, Mohammad (Supervisor) ; Taghizade, Mohammad (Supervisor) ; Roshanzamir, Manouchehr (Co-Advisor)
Abstract
Uranium dioxide (UO2) has been widely used as nuclear fuel in water cooled reactors since 1960s. UO¬2 is a refractory oxide with a melting point in excess of 28000C and therefore, requires high sintering temperature around 17000C in a hydrogen atmosphere for several hours. In the conventional method, the sintering is incorporated with indirect heating of green pellets in a refractory-type electrical resistance furnace. This furnace, however, uses a large number of expensive heating elements and refractory materials to achieve and maintain the high temperature for a long time. Moreover, it consumes much electrical energy and time. Since nanocrystalline materials contain a large fraction of...
Calculation of Biodex Balance Indices Using a Modified-wobble Board
, M.Sc. Thesis Sharif University of Technology ; Behzadipour, Saeed (Supervisor) ; Sanjari, Mohammad Ali (Supervisor)
Abstract
Maintaining balance is an essential need for human. This ability is sometimes lost or weakened due to reasons such as muscle weakness, vision problems, and neuromuscular problems. It was difficult to accurately measure balance parameters in the past because it needs expensive equipment and the presence of a physiotherapist. In new clinical setups, accurate measurements of balance quality have become possible using advanced devices. These devices are also used to provide therapeutic exercises to improve the balance condition. One of the most famous products in this area is the Biodex balance SD. The cost of this device, however, is high and it is for research and clinical use. The purpose of...
Robust control of a class of fractional order plants in the presence of pole uncertainty
, Article 26th Iranian Conference on Electrical Engineering, ICEE 2018, 8 May 2018 through 10 May 2018 ; 2018 , Pages 881-886 ; 9781538649169 (ISBN) ; Tavazoei, M. S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
In recent years some approaches for robust control of plants with uncertainty in their poles have been suggested. Recently a new approach for tuning controllers has been introduced that can preserve phase margin in desirable value despite large variations in location of one of the poles and also it is able to provide required gain crossover frequency in the nominal case. In this paper by benefiting from this approach, a fractional order proportional derivative controller is introduced to control the plants with fractional order transfer function with uncertainty in their poles with order in the range (1, 2). Also, sufficient conditions on design specifications and plant parameters for...
An efficient method for tuning of FOPI controllers: robustness to order variations of the plant
, Article 26th Iranian Conference on Electrical Engineering, ICEE 2018, 8 May 2018 through 10 May 2018 ; 2018 , Pages 821-826 ; 9781538649169 (ISBN) ; Tavazoei, M. S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Existence of uncertainties in the model of real-world plants can trouble the control system designer in achievement of control objectives in control of such plants. In modeling of these plants by benefiting from fractional order models, one of the most commonplace types of uncertainties is the order uncertainty. This paper deals with presenting a method for tuning fractional order PI (FOPI) controllers to be used in control of plants, modeled by fractional order transfer functions consisting of a fractional order pole in addition to a time delay, such that the control system is robust against order variations. By the proposed tuning method, values of phase margin and gain crossover frequency...
Analysis of Client Side Vulnerabilities in Microservice-based Systems
, M.Sc. Thesis Sharif University of Technology ; Kharrazi, Mehdi (Supervisor)
Abstract
Nowadays, software systems face many challenges that relate to their maintenance, scalability, and development. To address these challenges, many large software systems have moved away from monolithic architecture and adopted a microservicesbased architecture. However, microservices-based systems face security challenges due to their distributed nature, complex dependencies, and diverse implementation technologies. This study specifically examines architecture-based threats, which fall under the program logic-based category. Previous research has required access to the server-side architecture to recover the architecture of the system, but this study proposes a method for recovering the...
Synthesis of Alumina Support Modified with X and Y Zeolites as a Catalyst of Diesel Hydrodesulfurization Process
, M.Sc. Thesis Sharif University of Technology ; Kazemeini, Mohammad (Supervisor) ; Soltanali, Saeed (Supervisor) ; Rashidzadeh, Mehdi (Co-Supervisor)
Abstract
Environmental destructive effects of gases caused by combustion of sulfur compounds in the fuel, poisoning of catalysts, corrosion of equipment, as well as intensification of environmental considerations and new standards adopted for maximum sulfur content has made the desulfurization of fuels important; The desulfurization method using hydrogen has a high potential to remove sulfur. One of the major challenges in this process is to find the proper catalyst that has the best performance for this process. Ni (or Co) Mo (or W)/ γ-Al2O3 catalysts have high potential for using as a catalyst for the desulfurization process from a variety of large-scale or industrial hydrocarbon cuts. According to...
Synthesis of TiO2 nano powder by the sol-gel method and its use as a photocatalyst
, Article Journal of the Iranian Chemical Society ; Volume 7, Issue SUPPL. 1 , 2010 , Pages S154-S160 ; 1735207X (ISSN) ; Sharif University of Technology
2010
Abstract
In this work the titanium dioxide powder was prepared by the optimized and simple Sol-Gel method and then characterized. The gelling pH was set to values of 3 (TiO2-A), 7 (TiO2-N) and 9 (TiO2-B) to observe the effect on the properties of the material. In these three cases nanoparticulated materials were obtained with particle sizes between 10nm and 20nm. The larger surface areas were obtained at pH 3, which is several times larger than the others. Furthermore, with the gelling condition pH 3, it was possible to synthesize pure anatase phase titania. Some preliminary results on the test of the photocatalytic activity of the synthesized materials in the reduction of nitric oxide are presented....
Study on modification of colloidal silica surface with magnesium ions
, Article Journal of Colloid and Interface Science ; 2009 , Pages 379-383 ; 00219797 (ISSN) ; Sharif University of Technology
2009
Abstract
The prepared colloidal silica via ion exchange was modified by adding Mg+2 ions in the surface growth process of colloidal silica. The particle size of the modified colloidal silica was decreased by increasing the seed concentration, whereas that of colloidal silica was slightly increased as the seeds concentration exceed 15 wt%. But the trend of changes in surface area was completely reversed. Magnesium ions on surface of the modified colloidal silica were identified by the measurement of energy-dispersive X-ray spectrometry (EDS). After modifying with Mg+2 ions, the iso-electric point (IEP) of colloidal silica in pH ∼ 2 without modification, disappears over the whole pH range. © 2008...
Microwave-assisted extraction and high-throughput monolithic-polymer-based micro-solid-phase extraction of organophosphorus, triazole, and organochlorine residues in apple
, Article Journal of Separation Science ; Volume 39, Issue 3 , 2016 , Pages 576-583 ; 16159306 (ISSN) ; Es Haghi, A ; Basiri Pour, F ; Sharif University of Technology
Wiley-VCH Verlag
2016
Abstract
A high-throughput micro-solid-phase extraction device based on a 96-well plate was constructed and applied to the determination of pesticide residues in various apple samples. Butyl methacrylate and ethylene glycol dimethacrylate were copolymerized as a monolithic polymer and placed in the cylindrically shaped stainless-steel meshes of 96-micro-solid-phase extraction device and used as an extracting unit. Before the micro-solid-phase extraction, microwave-assisted extraction was employed to facilitate the transfer of the pesticide residues from the apple matrix to liquid media. Then, 1 mL of the aquatic samples was transferred into the 96-well plate and the 96-micro-solid-phase extraction...
Design and implementation of a robotic architecture for adaptive teaching: A case study on iranian sign language
, Article Journal of Intelligent and Robotic Systems: Theory and Applications ; Volume 102, Issue 2 , 2021 ; 09210296 (ISSN) ; Taheri, A ; Meghdari, A ; Alemi, M ; Sharif University of Technology
Springer Science and Business Media B.V
2021
Abstract
Social robots may soon be able to play an important role in expanding communication with the deaf. Based on the literature, adaptive user interfaces lead to greater user acceptance and increased teaching efficiency compared to non-adaptive ones. In this paper, we build a robotic architecture able to simultaneously adjust a robot’s teaching parameters according to both the user’s past and present performance, adapt the content of the training, and then implement it on the RASA robot to teach sign language based on these parameters in a manner similar to a human teacher. To do this, a word to teach in sign language, repetition, speed, and emotional valence were chosen to be adaptive using a...