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    Investigating the Microstructure, Mechanical Properties and Corrosion Resistance of Biodegradable Mg-Li-Zn Alloys

    , M.Sc. Thesis Sharif University of Technology Zohrevand, Mohammad (Author) ; Alizadeh, Reza (Supervisor) ; Tavakoli, Rouhollah (Co-Supervisor)
    Due to its biodegradability, magnesium can be a good option for making degradable medical implants that disappear in the body over time and thus there would be no need for secondary surgery. However, high rate of corrosion of magnesium in the body environment and low formability at room temperature are the two main problems of magnesium, which lead to rapid destruction of the sample in a short time and serious problems. For these reasons, much research is currently being done to improve the corrosion behavior and mechanical properties of magnesium alloys through microstructure modification. In this regard, special attention has been paid to Mg-Li alloys as the lightest magnesium alloys. The... 

    Investigation into the Effect of Adding Sr on Microstructure, Mechanical Properties and Biodegradability Behavior of Biodegradable Mg-Zn-Sr Alloys

    , M.Sc. Thesis Sharif University of Technology Gerashi, Ehsan (Author) ; Alizadeh, Reza (Supervisor)
    Biodegradable implants are new generation of implants that require no secondary surgery for their removal. Mg exhibits a great potential to be used as the biodegradable implant. However, mechanical properties and biocorrosion behavior of Mg are not suitable for being used as biodegradable implants. In this study, effects of Sr additions, heat treatments (T4 and T6), and multi-directional forging on the microstructural evolution, mechanical properties and biocorrosion behavior of Mg-4Zn-xSr alloys, and also the effect of hydrothermal coating on the biocorrosion behavior of Mg-4Zn-0.3Sr alloy were investigated. Potentiodynamic polarization and hydrogen evolution methods were used to... 

    Fabrication and Evaluation of Mechanical and Anti-corrosion Properties of Epoxy Resin/Carbon Nanofibers Containing Organic Corrosion Inhibitors

    , M.Sc. Thesis Sharif University of Technology Ghaderi, Mohammad (Author) ; Ramazani Saadat Abadi, Ahmad (Supervisor) ; Mahdavian Ahadi, Mohammad (Supervisor)
    To protect mild steel against corrosion, an intelligent self-healing epoxy (EP) coating including carbon nanofiber (CNF) modified with polydopamine (PDA)-La (III) complex was successfully fabricated. The high aspect ratio and unique thermal and electrical characteristics of CNF made it an ideal physical barrier against the penetration of corrosive ions. Due to the poor dispersion of CNF, its surface was modified using PDA. PDA, which contains functional groups such as catechol, amine, and imine, can mitigate corrosion reaction by generating the Fe-Catechol complex and also boost the coating's adherence to the metal surface, in addition to anchoring La3+ inorganic corrosion inhibitor.... 

    Deposition and Properties of ZIF-8/SiO2 Hydrophobi Anti-Corrosion Coating

    , M.Sc. Thesis Sharif University of Technology Tajaslan, Parisa (Author) ; Dolati, Abolghasem (Supervisor)
    In this research, a coating was created on the steel surface using the network structure of zeolite imidazolate-8 (ZIF-8) and its effect on the corrosion behavior of steel was investigated. Then, the effect of two coupling agents, mercaptopropyltriethoxysilane (MPTES) and aminopropyltriethoxysilane (APTES) on the coating and its anti-corrosion properties was investigated. Then, in order to make a hydrophobic coating, the substrate was first coated with ZIF-8 and then a combination of silica nanoparticles plus hexamethyldisilazane (HMDS) and polymethylhydrogensiloxane (PMHS) was added to the initial solution and then coating was done. As a result of this process, the contact angle of water... 

    Fabrication and Evaluation of Anti-Corrosion Properties of Epoxy/Modified Graphitic Carbon Nitride (g-3N4) Nanocomposite on Mild Steel

    , M.Sc. Thesis Sharif University of Technology Hassanzadeh, Abolfazl (Author) ; Ramazani Saadatabadi, Ahmad (Supervisor)
    In order to protect the corrosion of steel, a self-healing epoxy nanocomposite containing modified graphite carbon nitride (g-C3N4) and ZIF-67 was made along with benzotriazole (BTA) and cerium inhibitors. To increase the efficiency and also to increase the duration of use of inhibitors, it is better to load these inhibitors on containers such as MOFs. One of the useful MOFs for this purpose is ZIF-67, which has a high specific surface area that allows the transport of inhibitors with high capacity. But these containers fail after some time, so to improve the physical properties of the coating systems, g-C3N4 was also used as a mineral material, which of course was also used as a filler.... 

    Improving Mechanical and Biological Behavior of Mg-2ag Alloy: Effects of Y Addition, Heat Treatment and Coating

    , M.Sc. Thesis Sharif University of Technology Mohammadi Zerankeshi, Meysam (Author) ; Alizadeh, Reza (Supervisor)
    Biodegradable Mg-Ag alloys are promising implants for bone tissue regeneration due to their unique ability to reduce inflammation and infection after implantation with the presence of silver. However, their biological performance, including biodegradability, needs further improvement. In this regard, the effects of adding yttrium element, solution heat treatment and coating on the microstructure, biodegradability behavior, mechanical properties and biological characteristics of a cast Mg-2Ag alloy were studied. Addition of 1 wt% of yttrium caused grain refinement in the microstructure and solid solution heat treatment led to a significant decrease in the volume fraction of secondary phases.... 

    Super Hydrophobic Ni Coating on Steel by Electrodeposition Method

    , M.Sc. Thesis Sharif University of Technology Nakhaei Niya, Hamzeh (Author) ; Dolati, Abolghasem (Supervisor)
    In this study, the properties of super-hydrophobic Ni coating on carbon steel including wetting behavior and corrosion resistance of Nickel coatings deposited on the steel substrate were investigated. For this purpose, Nickel coatings deposited by electrodeposition method in deferent current density (10,20,30,50, 70 mA /cm2) in bath containing 1.5 mol of ethylene de-ammonium de-chloride, 0.5 mol H3BO3, 1 mol Nicl2.6H2o and then immersed in a bath containing 0.01 mol per liter myristic acid and ethanol for 24 hours and then placed in the room temperature for 14 days. Deferent tests were used for characterization, wettability properties, corrosion behavior and morphology of Ni coatings. The... 

    Synthesis of Polyurea for Use in the Coating Process

    , M.Sc. Thesis Sharif University of Technology Rouzbahani, Amir Reza (Author) ; Mousavi, Abbas (Supervisor)
    To produce polyurea, a secondary or higher amine must be combined with a diisocyanate. For this purpose, we first combined diethylenetriamine, and hexamethylene diisocyanate, which did not have good mechanical properties due to the aliphatic nature of the molecules. Then, instead of hexamethylene diisocyanate, we used MDI, which was mixed using a mechanical mixer but became a paste that was not suitable for coating applications. To reduce the viscosity of MDI, propylene carbonate was added to improve mixing, but the gel time also increased. Because the solvent was non-polar and the amine was polar, it was decided to add the solvent, amine, and polyvinyl alcohol as surfactants to allow faster... 

    Surface Treatment Effects on Fretting Fatigue Map of a Titanium Alloy

    , M.Sc. Thesis Sharif University of Technology Shariati Nejad, Ali (Author) ; Adib Nazari, Saeed (Supervisor)
    In contacts, the presence of both variable loading and low-amplitude movements causes a kind of fatigue in these components called FRETTING FATIGUE. fretting fatigue has reduced the life of parts. Due to the high cost of replacing some parts in case of failure, it is necessary to take effective measures to delay this exhaustion. One of the effective solutions that can be applied is the use of coating and surface treatments in the contact areas. In this research, first, the fretting fatigue maps of Ti-6Al-4V alloy have been calculated and drawn according to the recommendations of the ASTM standard by using finite element methods. In the next step, by using experimental experiments, the damage... 

    Investigation and Analysis of the Coating Effect on the Contact Pressure and Slip Amplitude in Fretting Fatigue of a Compressor Blade Root

    , M.Sc. Thesis Sharif University of Technology Amini Chehragh, Hassan (Author) ; Adib Nazari, Saeed (Supervisor)
    In many industrial devices and machines, variable loading is applied to the parts, which will lead to fatigue in these parts. Most of these components are in contact with other components, and when the device is operating, low-amplitude movements occur at the contact point. Variable loading conditions and low-amplitude movements at the point of contact can cause failure on parts called FRETTING FATIGUE. This type of failure occurs in many aerospace components, such as where the compressor blade roots connect to the disc. In recent years, many failures due to fretting fatigue has been reported, which has made the need to take solution to prevent this type of failure more and more obvious. One... 

    Estimation of Chitgar Lake Evaporation and the Impact of Chemical Coverings on its Reduction

    , M.Sc. Thesis Sharif University of Technology Nejatian, Amir (Author) ; Tajrishy, Masoud (Supervisor) ; Irajizad, Azam (Supervisor)
    Reducing water evaporation is one of the ways to overcome the low precipitation and drought conditions in water reservoirs. For this purpose, extensive studies have been investigated on physical and chemical coatings on lakes and reservoirs. Physical methods often involve the use of floating covers on the water surface to block evaporation by shading, most of which are only suitable for reservoirs with surface areas smaller than 5 hectares. In chemical methods, the evaporation can be decreased by nanomaterial coating, usually, containing long-chain molecules, which by spraying them on the surface, molecular monolayers are formed. In this study, the effect of nanometer coatings on the surface... 

    Aqueous Phase Reforming of Biomass Using Micro-reactor

    , M.Sc. Thesis Sharif University of Technology Entezary, Behzad (Author) ; Kazemeini, Mohammad (Supervisor) ; Mohammadi, Aliasghar (Supervisor)
    Consumption of oil and gas as energy carrier leads to irreversible environmental effects related to greenhouse gases emission. Hence, for the reduction in greenhouse gas emission, a shift to renewable resources for energy supply is recommended. However, in recent years, hydrogen has emerged as the most promising clean energy carrier for generating electrical power through fuel cells. Nevertheless, production of renewable hydrogen is the main barrier to the development of hydrogen as an energy carrier. Aqueous phase reforming of oxygenated hydrocarbon is developed by Dumesic for producing renewable hydrogen-rich gas with low CO. Since it is expected that, use of new technology such as the... 

    Investigating Different Methods of Coating the Polyaniline on Anode Electrode and its Effect on Microbial Fuel Cell Performance

    , M.Sc. Thesis Sharif University of Technology Ghasemi, Behzad (Author) ; Yaghmaei, Soheila (Supervisor)
    In this research, different methods of coating polyaniline on the anode electrode and its performance in a microbial fuel cell, and a chemical method for making polyaniline / graphene catalyst on a cathode electrode and its performance in microbial electrolysis cell electrode were investigated. There are two main goals in this study. First, the production of polyaniline and the comparison of the surface morphology of this fiber with other forms of polyaniline on the surface of the electrode and its effect on the performance of the microbial fuel cell and the second, the production of polyaniline / graphene catalyst in the cathode electrode and its comparison with the platinum catalyst in the... 

    Production of Vegetable Oil Biodiesel by Heterogeneous Catalytic Trans-Esterification Method in Micro-Reactor

    , M.Sc. Thesis Sharif University of Technology Piran, Samira (Author) ; Kazemeini, Mohammad (Supervisor) ; Mohammadi, Ali Asghar (Supervisor)
    The purpose of this study is to study heterogeneous nanocatalysts for the production of biofuels by the method of exchange of styrene using oil and methanol as a fossil fuel alternative. Preparation of nanocatalysts, performing characteristic tests and investigating the reaction in different operating conditions in the batch reactor has already been studied. Therefore, in this study, the production of biodiesel fuel using the trans-esterification of canola oil with nanocatalysts in the micro-reactor reactor will be discussed. Previously, a heterogeneous catalyst (lithium based on calcium-lanthanum) was constructed using a co-incineration method and a wet inoculum, and as active and stable... 

    Growth of Perovskite Film based on Lead Iodide by Controlling Deposition Parameters for Solar Cells Application

    , M.Sc. Thesis Sharif University of Technology Tafazoli, Saeedeh (Author) ; Mohammadi, Mohammad Reza (Supervisor) ; Seyed Reihani, Morteza (Supervisor) ; Riahi, Nastaran (Co-Advisor)
    Perovskite solar cells, with high efficiency operation, have been candidated as a cost-effective and environmentally friendly technology. Despite the great progress, there are some primarily issues remained regarding to the perovskite film and its fabrication methods. A very common perovskite cell structure is FTO/TiO2/CH3NH3PbI3/Spiro-OMeTAD/Au. Although, this structure has some advantages, lack of full surface coverage of perovskite film leads researchers to put much effort on finding other constructions. This surface inhomogeneity reduces the amount of light absorption and therefore efficiency. One way to produce a complete and uniform film is applying mixed-halide composition; such as... 

    Preparation and Characterization of ZrO2 Antistatic Coatings on Glass

    , M.Sc. Thesis Sharif University of Technology Naderi, Armaghan (Author) ; Dolati, Abolghasem (Supervisor) ; Afshar, Abdollah (Supervisor)
    In this study, the zirconia antistatic coating was synthesized by dip coating sol-gel route on glass substrate. The solution contains ZrCl4 as precursor and isopropanol as solvent to synthesize zirconium oxide. The effects of environmental humidity and solution concentration on the coating characterization were analyzed. MPTS and primer binder were added as binding agents in the solution to observe the effect of binding agents on the coating adhesion. Solution stability and antistatic coating characterization were analyzed by zita potential test, FTIR spectroscopy, EDX analysis, FESEM and AFM microscopy, pencil hardness test, thickness test, antidust ability and spectrophotometer. The... 

    A Microfluidic Platform for Mercaptane Removal from Liquefied Petroleum Gas

    , M.Sc. Thesis Sharif University of Technology Azizzadeh, Ali (Author) ; Mohammadi, Ali Asghar (Supervisor) ; Soltanieh, Mohammad ($item.subfieldsMap.e)
    Gas pollutants are included volatile inorganic compositions and odorous materials, which are harmful and dangerous for environment and human health. There are several methods for removing gas pollutants such as physical, chemical and biological methods. In this work, we discuss about ethyl-mercaptan adsorption in LPG by ZSM-5 zeolite and in use of micro systems (micro channels). This work is also concerned about micro channel coating by ZSM-5 and NaY zeolites on glass and the method of coating with (3-Chloropropyl) trimethoxysilane linker. After selecting the appropriate method for zeolite coating, we proceed to micro channel coating. In this research, four different designs of micro channel... 

    Creating a Protective Coating Against Corrosion and Erosion on the Surface of the Parts using in Sour Environments

    , M.Sc. Thesis Sharif University of Technology Ghasemi Tabasi, Hossein (Author) ; Kokabi, Amir Hossein (Supervisor)
    A concern in the production sour oil and gas is the corrosion caused by the acid gas H2S. Even though corrosion resistant alloys (CRA) have long been available as a material selection option that mitigates H2S corrosion, the carbon steel is in general more cost-effective for oil and gas facilities. The aim of this study is to investigate the mechanical properties of 410NiMo cladding on a low alloy steel substrate. In this investigation, two successive layers of ER410NiMo were clad on low alloy steel substrates. To reduce the likelihood of Hydrogen Induced Cracking (HIC) and producing stable hydrogen traps, Post Weld Heat Treatment (PWHT) was used. To characterize the mechanical properties of... 

    Formation and Investigation of Zinc-Nickel Two Cathionic Electrophospahte Coating Properties on Galvanized Steel

    , M.Sc. Thesis Sharif University of Technology Barati Darband, Ghasem (Author) ; Afshar, Abdollah (Supervisor)
    By using electrophoaphating treatment in the metal coating process, the operating temperature of chemical phosphating bath is decrease and also difficulties with the use of high temperature bath is eliminated. The aim of this study is investigate the effect of operating parameter on coating properties and also investigation the deposition mechanism of Zn-Ni electrophosphate coating. Coating properties such as morphology, corrosion resistance and porosity of the coating characterized using SEM, polarization test and electrochemical method respectively. The values used for pH effect was 1.6,1.8,2 and 2.2 results indicated that by increasing the pH value from 1.6 to 1.8 the icorr decrease from... 

    Cathodic Disbonding in Steel Structures and the Effect of Paint Type and Environment

    , M.Sc. Thesis Sharif University of Technology Sharbatdar, Meghdad (Author) ; Ghorbani, Mohammad (Supervisor)
    Although using cathodic protection in addition to coating with paint will extend the life of pipelines drastically, it can also accelerate disbondment of coating at coating defects. In this research four usual pipeline coating systems have been examined from applicational aspects and the best coating system among them has been introduced. The four coating systems were consisted of: epoxy coal tar 212 with epoxy 155 primer, solvent free polyamine epoxy 474HG without primer, glasscote 440 witout primer and glasscote 440 with epoxy 155 primer. According to ASTM G8, cathodic disbondment test was accomplished for eight samples simultaneously. During the tests cathodic protection current and...