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Preparation and Investigations of Flexible Supercapacitors Using Nanocomposites with Graphene-based Structures and Layered double hydroxide Ni/Co and Manganese Molybdate
, Ph.D. Dissertation Sharif University of Technology ; Shahrokhian, Saeed (Supervisor) ; Iraji-zad, Azam (Supervisor)
Abstract
In the first part of this research, for the first time, we introduced a flexible high performance graphene-based supercapacitor using silver fiber fabric as the current collector. The silver fiber fabric offers remarkable advantages such as light weight, mechanical flexibility and ease of integration with electronic textiles, which well-suited for wearable energy storage devices. A new hybrid material of graphene-silver fiber fabric (rGO/SFF) was prepared through a facile electrophoretic deposition of graphene and being used as a binder-free flexible supercapacitor electrode. In order to obtain the optimum condition, the effect of deposition time was investigated and a duration time of 10...
Fabrication and Investigation of Supercapacitors Based on Graphene Nanocomposites
, Ph.D. Dissertation Sharif University of Technology ; Iraji Zad, Azam (Supervisor) ; Shahrokhian, Saeed (Supervisor)
Abstract
Development of renewable energy production from sun and wind and the development of hybrid electric vehicles seem to be integral components in modern societies in order to overcome the environmental pollution and reduce the use of fossil fuel sources. In such devices energy storage plays an important role and supercapacitor is one the important energy storage devices. Structure of supercapacitor electrodes has considerable effect on supercapacitor performance. Graphene as a 2D carbon structure can improve electrochemical properties of electrodes. Here three different hybrid structure of graphene have been realized. The high capacitance and cyclic stability of graphene nanosheets decorated...
Study on Immobilization of the Spent Ion Exchange Resins of Tehran Research Reactor in Borosilicate Glass
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Yadollahi, Ali (Supervisor) ; Sepehrian, Hamid (Co-Supervisor)
Abstract
Considering the operation of the current nuclear reactors and the country's policy to achieve 10,000 megawatts of nuclear power in the horizon of 1420, as well as the construction of research reactors, we will face a huge amount of radioactive waste in the coming years. Meanwhile, spent ion exchange resins constitute a large amount of low and intermediate level (LILW) solid radioactive waste produced from the nuclear industry. Therefore, appropriate precautionary measures should be taken for the immobilization and disposal of these radioactive wastes in order to ensure the sustainable development of the nuclear industry and the protection of the environment and human health. In this study,...
Effect of Natural Ligands on Transport of Radionuclides in Soil Column of Naeen Repository
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor)
Abstract
Nuclear waste management in Iran is the responsibility of the Nuclear Waste Company. The waste company is obliged to bury waste with a certain level of radioactivity, resulting from various processes of the nuclear fuel cycle or other processes such as research projects and medical centers, after the necessary measures, finally at the Anarak landfill site. To evaluate the safety of the site, it is necessary to study the parameters of radioactive nucleation in the soil. Humic substances from natural substances in the soil affect the transport of radioactive nuclei. In this project, to study the effects of the presence of humic acid, the soil of Anarak residue in three weight percent...
Synthesis of Graphene by New Methods, and its Application for Adsorption of Cobalt
, M.Sc. Thesis Sharif University of Technology ; Outokesh, Mohammad (Supervisor) ; Shafiekhani, Azizollah (Supervisor)
Abstract
In this study graphene and graphene adsorbent for the Co2+ ion were created from sodium phenoxide and calcium phenoxide, respectively, using the chemical vapor deposition method, and their chemical, physical, and morphological properties were investigated using FT-IR, UV, XRD, Raman, TEM, FE-SEM, and XPS. The results suggest that the optimum reaction condition for synthesizing mono-layer and multi-layer graphene is the 750 °C temperature for 30 min. The Co2+ adsorbing properties of the synthesized graphene adsorbent from calcium phenoxide was investigated. The investigation of solvation properties suggests insolubility above 650 °C and the kinetic data suggest the rapidness of the Co2+...
Measurement of Radionuclides Transport Parameters for Soil Samples from Anarak Radioactive Waste Disposal Site by Collimated Gamma Ray Spectroscopy
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor)
Abstract
The Iranian Nuclear waste management Company is responsible for the safe disposal of the low-level radioactive waste resulting from the various processes of the nuclear fuel cycle and other radioactive-related activities. The safety assessment of waste disposal requires the measurement of transport parameters of radioactive nuclides in the soil around the disposal site.In this project, concentration profiles within a column which filled with Anarak Radioactive Waste Disposal Site soil were obtained using collimated gamma scanning method. Concentration profiles were measured at two different times (69 and 138 hours after injection). Then, using STANDMOD software, the equilibrium...
Measurement of Radionuclide Transport Parameters for Soil Samples Taken from Naein Radioactive Waste Disposal Site by Using Column Experiment and Determining the Concentration Profile through the Column
, M.Sc. Thesis Sharif University of Technology ; Samadfaam, Mohammad (Supervisor)
Abstract
Radioactive wastes are generated at different stages of the nuclear fuel cycle and other activities related to the handling of the radioactive substances. In order to protect human being and the environment from any harmful effects of ionizing radiation, it’s necessary to isolate radioactive waste by disposing them in near surface or deep geological formations (depending on the radioactive hazard). To ensure that the waste is properly isolated from the environment for required periods of time, the safety assessment of the disposal site is essential. Transport of radionuclides from the disposal site to the environment is the essential part at any safety assessment program. Therefore,...
Synthesis and Characterization of Graphene-based Material and Investigation of its Adsorption Properties for Radioactive Waste
, Ph.D. Dissertation Sharif University of Technology ; Outokesh, Mohammad (Supervisor)
Abstract
Nuclear power is a prominent alternative of fossil fuels that can effectively solve global warming, acid rains and other consequences of air pollutions, caused by combustion. Despite such obvious advantage, this highly compact form of energy suffers from a big problem corresponding to its nuclear waste. Graphene oxide (GO), a lamellar material with wide range of surface functional groups such as epoxy (C-O-C), hydroxyl, and carboxyl offers large surface area as well as high sorption capacity for the metallic cations. This thesis study presents a supercritical, and co-precipitation synthesis of magnetite- graphene oxide (M-GO) in which Fe3O4 nanoparticles are simultaneously formed, surface...
Removal of Radioactive Elements from Liquid Waste of Bushehr Nuclear Power Plant with Resin
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Sepehrian, Hamid (Supervisor) ; Fasihi, Javad ($item.subfieldsMap.e)
Abstract
In this study, granular activated carbon has been modified by potassium nickel hexacyanoferrate ( KNCF), sodium dodecyl sulfate(SDS) and ammonium per sulfate(APS) as new adsorbents for cesium, cobalt and chromium(VI), respectively. The prepared adsorbents were characterized using powder X-ray diffraction(XRD), nitrogen adsorption-desorption isotherm data, infrared spectroscopy, scanning electron microscopy coupled with energy dispersive spectroscopy(SEM-EDS) and their adsorption performance were investigated. The effect of various parameters like the initial pH value of the solution, contact time, temperature, strength ionic of the solution, interference ions and the initial concentration of...
Experimental Study of Pendulum Grinding of Superalloys
, M.Sc. Thesis Sharif University of Technology ; Akbari, Javad (Supervisor)
Abstract
Superalloys are widely used in aerospace and power industries due to the good performance at high temperatures for examples gas turbines, steam turbines and aircraft components. In addition to the turbines cobalt-base superalloys are used in medical implants such as knee and hip joints. The main strengths of the superalloys are heat-resistant, retaining their high mechanical and chemical properties at high temperatures, high melting temperatures, high corrosion resistance, resistance to thermal fatigue, thermal shock, creep, and erosion. Because of difficult to machine properties of superalloys, grinding is one of the effective methods for machining superalloys. The surface integrity of the...
Investigating the Microstructure and Physical and Mechanical Properties of Composite Lead-Free Solder Containing Ferromagnetic Particles
, M.Sc. Thesis Sharif University of Technology ; Movahedi, Mojtaba (Supervisor)
Abstract
The use of tin-lead solder alloys (Pb-Sn) has been limited due to environmental problems in recent years, and several types of research are being carried out on lead-free solder alloys. However, these solders have weaker physical and thermal properties than Pb-Sn solders. In recent years, researchers have been trying to improve these solders' physical and mechanical properties by adding reinforcing particles to the solder and using a magnetic field during melting and solidifying the solder. On the other hand, with the growth path of miniaturization and, simultaneously, compaction and integration of electronic equipment, electronic circuits should have higher current density, better...
Corrosion Behavior of TLP Bonded 304 Stainless Steel Using Cobalt Base Interlayer
, M.Sc. Thesis Sharif University of Technology ; Ekrami, Ali Akbar (Supervisor) ; Tavakoli, Rouhollah (Supervisor)
Abstract
The transient liquid phase bonding is a combination of penetration bonding and hard soldering processes. This method is based on the diffusion in the solid state of the melting point reducing elements from the joint zone into the base metal and isothermal solidification that the kinetics of this reaction are controlled by diffusion in the solid state. In this study, we investigate the bonding of 304 stainless steel with cobalt base interlayer by transient liquid phase method and studies of microstructural and corrosion resistance of the joint. Three different temperatures are considered for the bonding and after each bonding, the microstructure is examined with a optical and scanning...
Investigation and Study of Microstructure, Dielectric and Non-ohmic Properties of tin and Cobalt Oxide Systems Co-Doped with Electron Donor and Acceptor Elements
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor) ; Maleki Shahraki, Mohammad (Supervisor)
Abstract
In recent years, there are continuous researches on replacing new dielectrics with suitable dielectric properties (including high dielectric coefficient, low loss factor, high breakdown voltage, and high nonlinear coefficient simultaneously). One of these new materials is co-doped titanium oxide with donor and acceptor of electron, which in spite of having high dielectric coefficient and low loss factor. it has low breakdown voltage and researches on improving the disadvantages of this dielectric are ongoing. Due to the structural similarities between tin oxide and titanium oxide, the tin oxide can be an interesting system for studying and improving disadvantages in this field. In this study...
Investigation of Creep Properties of Transient Liquid Phase Bonding of FSX-414 Co-based Superalloy
, M.Sc. Thesis Sharif University of Technology ; Ekrami, Ali Akbar (Supervisor)
Abstract
The repair and production of Ni-based and Co-based superalloy parts have high importance in Oil and Gas, and Aerospace industries. Due to this issue, Transient Liquid Phase bonding is one of the most reliable welding methods for repair parts and fabricating new parts.In the present study, creep properties of similar transient liquid phase bonding of FSX-414 Co-based superalloy has been investigated and compared with creep properties of the un-bonded base metal. Firstly, the optimum condition of the bonding process was resulted from microstructural observations from different bonding conditions. Then, cylindrical samples for the aim of creep test specimens were fabricated in two different...
Molecular Dynamics Study of Tungsten and Iron Addition on the Glass Formability of Cobalt-based Electrodeposited Coatings
, M.Sc. Thesis Sharif University of Technology ; Tavakoli, Rouhollah (Supervisor)
Abstract
Recent research suggests that the electrochemical deposition of cobalt-based binary alloys, such as cobalt-tungsten and cobalt-iron, can lead to the formation of amorphous structures in the coatings. Theoretical studies suggest that these structures are equivalent to structures created by the melt cooling of the alloy at speeds of about 〖10〗^10 Kelvin per second. The formation of a glass phase can significantly increase the abrasion resistance and corrosion resistance of these coatings. Empirical studies show that the ability of the glass to become glassy, or more precisely, the transition from crystalline to amorphous, is largely a function of the chemical composition. Simulation of...
The Effect of Cobalt on Thermal Expansion and Metallurgical Properties of LM13 Alloy
, M.Sc. Thesis Sharif University of Technology ; Varahram, Naser (Supervisor)
Abstract
LM13 Aluminum alloys contain Silicon, Copper, magnesium and Nickel. This alloys have been widely used in automobile pistons. For this application thermal expansion coefficient is one important characteristics other than mechanical properties. In this project replacing Cobalt with Nickel to improve alloy thermal and mechanical properties in piston applications by different cobalt contents. Cobalt contents is 0, 0.15, 0.55 and 0.77 Wt%. Because of oxidation magnesium content decrease into 0.98, 0.74, 0.61 and 0.48 Wt%. Thermal expansion coefficient and UTS first increase and after 0.55 Cobalt Wt% show decrease But yield strength and hardness increase as cobalt content increase. Microscopic...
Influence of Temperature on Microstructure and Performance of a Lithium-ion Battery
, M.Sc. Thesis Sharif University of Technology ; Asgari, Sirous (Supervisor)
Abstract
In this study, the effect of temperature on the microstructure and electrochemical properties of the NMC batteries has been studied. An extensive set of accelerated aging tests has been carried out employing a Li-ion high energy 18650 system (2.2 Ah, negative electrode: carbon, positive electrode: Li(Ni0.5Mn0.3Co0.2) O2. Different influence factors on cycle aging, such as temperature and discharge rate have been investigated. The aged 18650 cells have been inspected via scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), impedance spectroscopy, and X-ray diffraction (XRD) after disassembly to find more information about the chemical reasons of the degradation and...
Microstructure-mechanical Properties Relationship of Transient Liquid Phase Bonded 304 Stainless Steel With a Co-based Interlayer
, M.Sc. Thesis Sharif University of Technology ; Ekrami, Ali Akbar (Supervisor)
Abstract
Stainless steels have many applications in different industries like chemistry, medicine and food production. So for using these alloys it is necessary to join them with appropriate method. In this research, microstructure-mechanical properties relationship of 304LC austenitic stainless steel transient liquid phase bonded using a Co-based interlayer was investigated. For this purpose, bonding was conducted at 1180 ℃ for different holding times. Microstructure of the joints was evaluated by optical microscopy (OM) and Scanning Electron Microscopy (SEM). The results showed that isothermal solidification (IS) was completed within 1800s and no intermetallic compound was formed in the joint area...
Application of TiO2 Nanotubes Fabricated by Anodizing of Titanium as a Suitable Substrate for Deposition of Active Materials for Use in the Supercapacitors
, Ph.D. Dissertation Sharif University of Technology ; Gobal, Fereydoon (Supervisor)
Abstract
In this thesis, the improving effects of TiO2 nanotubes (TiO2NTs) fabricated by anodizing of titanium as suitable substrate for deposition active materiales in supercapacitors were considered. PANI/Pd/TiO2NTs electrodes with highly porous structures and good capacitive characteristics were prepared by electrodeposition of polyaniline on palladium nanoparticles loaded TiO2 nanotubes. The results illustrated that the specific capacitance of these electrodes was around 1060 Fg−1 in 1.0 M H2SO4 electrolyte as measured at a constant current of 2.0 Ag−1, whereas it was 210 Fg−1 for the PANI/TiO2NTs electrode. NiO-ZnO/TiO2NTs electrodes were synthesized by the electrodeposition of...
Copper-cobalt/Tungsten Carbide Nano-composite Coatings Deposited on Pure Copper Substrate by Electrochemical Deposition
, M.Sc. Thesis Sharif University of Technology ; Abachi, Parvin (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
In this research a copper- Tungsten carbided nanocomposite coating prepared by electrodeposition from a sulfate bath in order to increase the hardness and erosion resistance of cooper without loosing cooper's specific physical properties as like as electrical and thermal conductivity. Various parameters were evaluated for finding significant factors in electrodeposition of Cu-Co/WC composite. Current density and concentration of WC and SDS were selected as affective factors. The morphology and structure were characterized by XRD and SEM. The mechanical properties of the coatings, such as hardness, wear resistance and surface roughness were studied with Vickers hardness indentation; pin on...