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    Lanthanum Chromite Coating on Stainless Steel by sol–Gel Dip Coating Technique

    , M.Sc. Thesis Sharif University of Technology Rashtchi, Hamed (Author) ; Faghihi Sani, Mohammad Ali (Supervisor)
    Because of the high operating temperature, interconnect surface tends to be oxidized and Cr2O3 oxide layer will be created on the surface. This phenomenon is undesirable due to decreasing electrical conductivity, so a preservative coating is needed to improve the interconnect properties. In this paper, a dense perovskite thin film was successfully synthesized on a ferritic stainless steel (type 430) substrate by a sol-gel dip coating method. This coating improved chemical stability, oxidation behavior of the substrate and decreased cathode poisoning. The lanthanum chromite was coated on the substrate by sol-gel dip coating process. First, during a hydrolyze process, a stable sol was made up... 

    Finite Element Formulation for Thermo-elastic Analysis of Functionally Graded Coating on Axisymmetric Shell Structures

    , M.Sc. Thesis Sharif University of Technology Ahmadi Kazemabadi, Abolfazl (Author) ; Hosseini Kordkheili, Ali (Supervisor) ; Zabihollah, Abolghasem (Co-Advisor)
    In this paper, a finite element formulation is presented to study the thermoelastic behavior of Functionally Graded (FG) axisymmetric coating in shell structures. The power law distribution model is assumed for the composition of the constituent materials in thickness direction. The Plasma Spray with multi steps coating method is considered for coating method. The procedure adopted to derive the finite element formulation contains the analytical through-the-thickness integration inherently. So the explicit through-the-thickness integration becomes possible after defining a two-noded, three parameters degenerated axisymmetric FG element. The nonlinear heat transfer equation is used for... 

    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... 

    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.... 

    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.... 

    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... 

    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... 

    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... 

    , M.Sc. Thesis Sharif University of Technology Javidi Sofiani, Mahyar (Author) ; Ramezani Saadat, Ahmad (Supervisor)
    Polymer flooding can yield considerable increase in percentage recovery. However, there are limitations with the existing polymer flooding technology, such as thermal, mechanical, bacterial degradation, surface absorption and undesirable plugging. A novel nanocore shell structure of polyacrylamide and polystyrene designed and prepared to intellectually control mobility ratio in oil reservoirs and overcome weakness and limitations of classical polymer flooding. Polyacrylamide particles have been obtained using spray drying of dilute solution of polyacrylamide. Then, polystyrene shell has been produced on polyacryamide particles by in-situ polymerization of styrene monomer in hydrophobic... 

    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... 

    Preparation and Characterisation of Titania-hydroxyapatite-carbon
    Nanotube Nanostructured Bioceramics by Sol-gel Process

    , M.Sc. Thesis Sharif University of Technology Majidnia, Elahe (Author) ; Mohammadi, Mohammad Reza (Supervisor)
    Hydroxyapatite (HA) is an attractive biomaterial due to its close chemical composition to bone and teeth. However, HA is brittle and has low strength under bearing loads, resulting in limition for orthopedic and dental applications. Two creative approaches have been developed to overcome this problem, using bioactive HA as coatings on metallic implants or as ceramic/metal composites. Carbon nanotubes (CNT) possess excellent mechanical properties to play the role as reinforcement for imparting strength and toughness to brittle hydroxyapatite (HA) bioceramic coating. Moreover, The addition of TiO2 to HA coatings has attracted considerable attention, since TiO2 is capable of increasing the... 

    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... 

    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.... 

    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... 

    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 Optimization of Ni-P-Zn Electroless Alloy Coatings

    , M.Sc. Thesis Sharif University of Technology Kordijazi, Amir (Author) ; karam, SaeedAllah (Supervisor) ; Dolati, Abolghasem (Supervisor)
    An optimization condition for obtaining Ni-Zn-P electroless alloy coating has been developed. The sulphate bath with sodium hypophosphate as a reducer and sodium citrate and ammonium chloride as complexing agents were used. The effect of variation in the pH level , temperature , time of deposition and reactants concentration on stability of bath, coating composition, microstructure, microhardness and corrosion resistance of coatings was investigated. The composition of coatings was obtained by using the EDAX analysis. To investigate coating morphology, SEM images were taken and to study the corrosion behavior of coatings potentidynamic polarization, Electrochemical Impedance Spectroscopy... 

    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... 

    An investigation on the Microstructure and Properties of Alumina-Carbon Nanotube (CNT) Nanocomposite Produced by Conventional and Microwave Sintering

    , M.Sc. Thesis Sharif University of Technology Ghobadi, Hossein (Author) ; Nemati, Ali (Supervisor) ; Sadeghian, Zahra (Supervisor) ; Ebadzadeh, Toraj ($item.subfieldsMap.e)
    Carbon nanotubes were coated with boehmite nanoparticles by sol gel method. According to the TGA analysis, formation of gamma-alumina from boehmite was at 500 . SEM investigation revealed the uniform coverage of gamma-alumina nanoparticles on the surface of CNTs. Composite powders containing 1, 2 and 3vol% of coated CNTs were produced by mixing the coated CNTs with alumina suspension. Phase analysis of composite powder calcined at 500 showed the complete decomposition of boehmite and formation of gamma-alumina. Samples were shaped by cold isostatic pressing at the pressure of 180MPa and sintering was performed using two different methods of conventional and microwave. Existance of the CNTs... 

    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... 

    Characterization of Nanohydroxyapatite-Carbon Nanotube on Stainless Steel 316L Produced by Sol-Gel Method

    , M.Sc. Thesis Sharif University of Technology Mohamadi, Pouya (Author) ; Nemati, Ali (Supervisor) ; Sadeghian, Zahra (Supervisor)
    In this investigation, hydroxyapatite-carbon nanotube nano composite coatings were applied on the 316L stainless steel implants. After polishing with 1200 sand paper, stainless steel implants were coated via dip coating method. The specimens were heat treated at 350˚C after being coated with HAP and HAP-CNTs composite. In vitro test was done in simulated body fluid (SBF) in 1 to 4 weeks periods. XRD evaluation of powder obtained from sol-gel process, showed the presence of HAP and CNTs in the powders. Comparison of XRD results of HAP and HAP-CNTs powders showed the better crystalinity of composite hydroxyapatite. After in vitro tests, specimens were studied with atomic force microscope (AFM)...