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Design and Implementation of an Optical Intrinsic Signal Imaging System for Brain by Using Intensity Magnification Algorithm
, M.Sc. Thesis Sharif University of Technology ; Fardmanesh, Mahdi (Supervisor) ; Ghazizadeh Ehsaee, Ali (Supervisor)
Abstract
In many neuroscience studies, the aim is to investigate the functional role of a population of neurons in response to a certain stimulus. Electrophysiology methods usually can only record from a small population of neurons and this is not sufficient for studying functional properties of the cortex. An alternative is to use functional neuroimaging methods. However, some of these methods are expensive and also they do not offer suitable spatial and temporal resolutions. Optical imaging systems can solve these problems because they are low-cost, easy to design, and also have good temporal and spatial resolutions. These systems can generate functional maps from the brain. In this study, a...
Investigation of Hydrodynamic Interaction between a Squat Submarine Operated behind a Ship
, Ph.D. Dissertation Sharif University of Technology ; Abbaspour, Madjid (Supervisor) ; Mohtasham Dolatsahhi, Kiarash (Supervisor) ; Sani, Mahdi (Co-Supervisor)
Abstract
This research investigates the hydrodynamic interaction of a squat submarine operating behind a ship in various wave and resistance experiments for towing and self-propelling arrangements. A one-tenth scaled captive model of a 0.625 m squat submarine is constructed along with a 1.5 m Fridsma ship to perform 116 unique experiments in a 4×6×400 m3 tank located in a towing tank center. The submarine is a new midget-submersible, of Apam-Napat SMSD type, with an L/D ratio below four. The cable is specified, regarding its weight per unit length, using a scaling method introduced in this research. Wave and resistance tests are performed for various 2D relative lengths and depths at short-distance...
Hydrodynamic Performance of Squat Submarine Equipped with Passive Pressure Drag Reductions
, Ph.D. Dissertation Sharif University of Technology ; Abbaspour, Madjid (Supervisor) ; Mohtasham Dolatshahi, Kiarash (Supervisor) ; Sani, Mahdi (Co-Supervisor)
Abstract
This research empirically examines the hydrodynamic performances of squat submarines under the resistance and wave tests, besides the numerical investigation of pressure drag reduction techniques. Submarines are limited for public use due to military classification issues and being expensive. This research introduces a new squat submarine in order to enable underwater exploration. This squat submarine has a 9- person capacity as a manned midget submersible using specific geometries of length-over-depth ratios (L/D) below four. The cause of such selection is to provide better visibility for the passengers to research and explore the sea. However, the geometrical features considerably change...
Preparation, Surface Modification and Application of Nanocomposite Membranes Based on Transition Metals- Dichalcogenide Nanoparticles in Forward Osmosis Desalination Process
, Ph.D. Dissertation Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor) ; Ahadian, Mohammad Mahdi (Supervisor) ; Amini, Mojtaba (Supervisor)
Abstract
Different parts of this research are focused on developing FO membranes and improving their performance. For this purpose, thin film composite (TFC) membranes with fixed composition of polyethersulfone/polyamide (PES/PA) have been used to investigate the effect of nanocomposites containing transition metal dichalcogenides (TMDs) on their performance. The support layer in all cases is PES, which is prepared through the phase inversion process and does not contain any nanofillers. The modification process takes place in the polyamide layer by dispersing the desired nanoparticles in the aqueous monomer solution necessary to form this active layer. Identification and characterization of...
Investigation on Effect of Additives on the Synthesis of Mesoporous Silica Nano Particles for Drug Delivery Applications
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor) ; Akbari, Hmid (Supervisor) ; Khoobi Shourkaei, Mahdi (Co-Supervisor)
Abstract
In recent years, the use of mesoporous silica nanoparticles as carriers of biological agents has increased. The use of nanometer dimensions in intra-body applications not only hides the particles from the view of macrophages and the body's immune system, but also causes the particles to enter the cells more easily through endocytosis. Template removal method is the most common method in the synthesis of mesoporous silica. In this method, the orderly arrangement of pattern-forming molecules is used to form pores. Until now, various types of organic materials have been used as pattern materials. The main goal is the synthesis of nanoparticles with the largest size of holes and the largest...
Experimental Study on the Efficiency of Memberane Bioreactor (MBR) in Removal of Trace Persistent Pollutants
, M.Sc. Thesis Sharif University of Technology ; Borghei, Mahdi (Supervisor) ; Vosoughi, Manuchehr (Supervisor) ; Hesampour, Mehrdad (Supervisor)
Abstract
The removal of glyphosate, one of the most widely used herbicide, with membrane bioreactor (MBR) was studied. Beside of glyphosate, the synthetic wastewater contained molasses and other salts as nutrient source. The membrane was made from polypropylene and was immersed in the bioreactor. The COD of the feed was adjusted by varying the ratio of glyphosate to molasses. The total COD was 500, 750 and 1000 mg/L. The resulted showed that when the bioreactor coupled with membrane the removal efficiency increased. The increase was attributed to higher concentration of biomass or MLSS in the MBR. The average of MLSS in the MBR was 8500 mg/L while in bioreactor without cell recycling and in batch...
Synthesis and Characterization of TiO2 Nanoparticles for Enhanced Oil Recovery Applications
, Ph.D. Dissertation Sharif University of Technology ; Taghikhani, Vahid (Supervisor) ; Ahadian, Mohammad Mahdi (Supervisor) ; Vosoughi, Manouchehr (Co-Advisor)
Abstract
Enhanced oil recovery (EOR) techniques are gaining more attention worldwide as the proved oil is declining and the oil price is hiking. Although many giant oil reservoirs around the world were already screened for EOR processes, the main challenges such as low sweep efficiency, costly techniques, possible formation damages, transportation of huge amounts of EOR agents to the fields especially for offshore cases and the lack of analyzing tools in traditional experimental works, hinder the proposed EOR process.It has been shown that recently, nanoparticles are attractive agents to enhance the oil recovery at the laboratory scale.
In this study TiO2 nanoparticles were used to improve...
In this study TiO2 nanoparticles were used to improve...
Investigation of Effective Parameters on Performance of Microfluidic Microbial Fuel Cell–Microbial Electrolysis Cell Coupled System
, M.Sc. Thesis Sharif University of Technology ; Bastani, Dariush (Supervisor) ; Yaghmaei, Soheila (Supervisor) ; Mardanpour, Mohammad Mahdi (Co-Supervisor)
Abstract
This study presents the experimental investigation of the microfluidic microbial fuel cell – microbial electrolysis cell coupled system as a bioenergy generator to produce biohydrogen without any external power supply. The effect of microbial fuel cells number (to provide the required potential for microbial electrolysis cell), the type of substrate and its concentration were assessed. The maximum produced hydrogen of 25, 33 and 50 ppm were obtained in flow rate of 200 μl h-1 and glucose concentration of 200 mg l-1 in 1, 2 and 3 stack MFCs, respectively. For urea solution, by combination of 1, 2 and 3 stack MFCs in the flow rate of 200 μl h-1 and the concentration of 800 mg l-1, the maximum...
Experimental and Numerical Investigation of Eel Hydrodynamics
, M.Sc. Thesis Sharif University of Technology ; Abbaspour Tehrani, Majid (Supervisor) ; Khorasnachi, Mahdi (Supervisor) ; Shafiei, Mohammad Behshad (Co-Supervisor)
Abstract
In the present study, the objective was to obtain the forward and backward swimming equation for the fiery eel and the European Eel in the experimental section. Then, by processing the videos, swimming equations were extracted. The obtained equations were used to move the 3D eel geometry of the STAR-CCM + software. The purpose of numerical modeling is to study the effect of body amplitude and wave frequency on the forces applied on the eel body during swimming. Numerical simulations were performed for the three amplitudes of 0.1, 0.115, and 0.138m and four different frequencies of 1, 1.2, 1.2 Hz, and Reynolds number 3857. The results of numerical work show us that the increase in the wave...
The Effect of Nominal Price on Stock Returns in Tehran Stock Exchange
, M.Sc. Thesis Sharif University of Technology ; Ebrahimnejad, Ali (Supervisor) ; Barakchian, Mahdi (Co-Supervisor) ; Keshavarz Haddad, Gholamreza (Co-Supervisor)
Abstract
Based on modern finance theory, valuation should not depend on nominal stock prices. However, evidence shows that the nominal price of stocks does matter in the U.S. stock market. In this paper, we examine the effect of nominal share prices on stock returns, using data between 2009 and 2017 form the Tehran Stock Exchange. Our results indicate that there is no significant relationship between nominal price and return on the Tehran Stock Exchange. By controlling for different important variables, the return differential between high price and low price stocks is insignificant and the results are robust to various specifications and tests. Furthermore, by using event study under the market...
A Systematic Approach for Biomarker Identification in Autism Spectrum Disorder based on Machine learning
, M.Sc. Thesis Sharif University of Technology ; Jafari Siavoshani, Mahdi (Supervisor) ; Kavousi, Kaveh (Co-Supervisor) ; Ohadi, Mina (Co-Supervisor)
Abstract
Autism spectrum disorder (ASD) is a strong genetic perturbation that encompasses a wide range of clinical symptoms, including functional at different regions of the brain, repetitive behaviors, and interests, weaknesses in social relationships, some sensitivities to environmental factors and etc. Genetic complexity and the impact of environmental factors put the disease in the category of Level 1 complex developmental disorders.We proposed a pilot, combined, and highly effective structure to identify biomarkers in the autism spectrum disorder that could be extended to other diseases that have a similar genetic architecture with autism. We also develop a Gene-tissue interaction network to...
Insight into the corrosion inhibition of Biebersteinia multifida root extract for carbon steel in acidic medium
, Article Science of the Total Environment ; Volume 836 , 2022 ; 00489697 (ISSN) ; Soltani, N ; Tavakkoli, N ; Nejatian, A ; Ebrahimian, J ; Mahdi, M. A ; Salavati Niasari, M ; Sharif University of Technology
Elsevier B.V
2022
Abstract
In this project, the protective effect of Biebersteinia multifida root extract (BMRE) against corrosion of 1018 low carbon steel (1018LCS) in HCl solutions was appraised by assessing weight loss, electrochemical impedance spectroscopy (EIS), and polarization at 25 °C. The maximum inhibitory efficacy for the concentration of 1 g/l of the BMRE was 92.8% at 25 °C after 2 h and increased to 95.3% after 24 h of immersion. Polarization experiments have shown that the extract in acidic solutions can act as a mixed corrosion inhibitor. The corrosion inhibitory efficacy of BMRE decreased with increasing temperature, and at all temperature settings studied, the adsorption of BMRE molecules on 1018 LCS...
Numerical Modeling of Surgical Lights Effects on the Operating Room Enviroment
, M.Sc. Thesis Sharif University of Technology ; Saeeidi, Mohammad Hassan (Co-Advisor) ; Kazemzadeh Hannani, Siamak (Co-Advisor) ; Sani, Mahdi (Co-Advisor)
Abstract
Cleanrooms have a broad scope of applications from electronics, pharmacy, biotechnology to hospital industries, and are susceptible to fine and ultra-fine particles. In this work operating room in the category of hospital applications is chosen. Airborne particles in the operating room depends on many factors such as room geometry, inlet and outlet design, air displacement rate, obstacles, etc. Surgical light is one of the most critical obstacles in the operating room as it is upstream to the surgery zone. The study presented in this thesis aimed to numerically investigate the influence of radiation emitted from the medical lamps on the indoor airflow quality in operating room environment....
The Effects of Tachyonic Instabilities and Non-Gaussian Perturbations During Cosmic Inflation and Reheating
, Ph.D. Dissertation Sharif University of Technology ; Firouzjahi, Hassan (Supervisor) ; Golshani, Mehdi (Co-Advisor) ; Sheikh Jabbari, Mohammad Mahdi (Co-Advisor)
Abstract
The cosmic inflation paradigmwas first introduced as a possible solution to the standardBig Bang cosmology problems. [1]. The inflationary models not only provide a solutionfor so the called flatness and horizon problems, but also they predict perturbations asprimordial seeds of large scale structures of Universe. Inflationary models can connecthigh-energy physics to the experiments. There is a mutual relation between inflationand high energy physics. It is necessary to find a fundamental description of inflationarymechanism and on the other hand the observational predictions of inflationary modelscan put bound on free parameters of associated fundamental theories. Thanks to vastdata...
Effects of Wind Shear Flow on the Aeroelastic Performance of a Large-Scale Wind Turbine with UBEM
, M.Sc. Thesis Sharif University of Technology ; Ebrahimi, Abbas (Supervisor) ; Taeibi-Rahni, Mohamad (Supervisor) ; Rezaei, Mohamad Mahdi (Co-Supervisor)
Abstract
Study of the structural flexibility of large-scale wind turbine components on aeroelastic performance is important under the existence of critical atmospheric conditions. Prediction and control the critical deformations, identifying maximum local deformation and modeling the forces involved, are required. Aeroelasticity analysis is a suitable method for studying the coupling effects of wind turbine aerodynamics, dynamics and structures. This research has been done by modeling wind turbine components including blades, hub, nacelle and tower, taking into account aerodynamic couplings, dynamics and structures. Considering the large scale of reference wind turbine, nonlinear equations have added...
Synthesis And Preparation of SiBNC Nanofibers
, M.Sc. Thesis Sharif University of Technology ; Faghihi Sani, Mohammad Ali (Supervisor) ; Mahdi Navaz Eghdam, Rouhoulah (Supervisor)
Abstract
Amorphous SiBNC ceramics have been developed as new high temperature materials. They show a high resistance against crystallization, high mechanical properties, low density, and high oxidation stability. Three synthesis methods have been developed for synthesis of SiBNC ceramics namely, Reactive magnetron sputtering, Mechanical alloying plus sintering, and polymer-derived ceramics. In this research among polymeric methods one pot synthesis due to high ceramic yield and high mechanical properties have been chosen. Two major methods for nanofiber preparation are Meltspinning and Electrospinng. It is notable that all of researches for SiBNC Nanofiber preparation has been conducted on...
Innovative overview of SWRC application in modeling geotechnical engineering problems
, Article Designs ; Volume 6, Issue 5 , 2022 ; 24119660 (ISSN) ; Fazel Mojtahedi, F ; Azizi, S ; Mahdi, H. A ; Ramani Sujatha, E ; Ebid, A. M ; Golaghaei Darzi, A ; Aneke, F. I ; Sharif University of Technology
MDPI
2022
Abstract
The soil water retention curve (SWRC) or soil–water characteristic curve (SWCC) is a fundamental feature of unsaturated soil that simply shows the relationship between soil suction and water content (in terms of the degree of saturation and volumetric or gravimetric water content). In this study, the applications of the SWRC or SWCC have been extensively reviewed, taking about 403 previously published research studies into consideration. This was achieved on the basis of classification-based problems and application-based problems, which solve the widest array of geotechnical engineering problems relevant to and correlating with SWRC geo-structural behavior. At the end of the exercises, the...