Sharif Digital Repository

Sharif University of Technology Plasma Focus (SUT-PF) is a Mather Type DPF device which has a 39 μF capacitor bank with 14 KV charging ability at its ultimate limit corresponding to 7 KJ stored energy. In the first step of this experiment, a test has been done at three distances 5, 7, 10 cm from anode tip with the different number of shots 20, 30, and 40 at 0 constant angles.In the following, a test is done at 5 and 10 degrees with 40 shots, and PF chamber has been filled up with nitrogen gas. Various tests have carried out for survey of this experiment, the result of which are as follow:The X-ray diffraction (XRD) analysis are used in order to reveal if the Nickel or Nickel nitride have... 

Capturing the atmospheric CO2 and turning it into value added products is a topic that has been extensively studied in recent years. One of the methods through which CO2 is valorized is via converting it into carbon nanofiber, CNFs. CNFs can be an important material in future human activities due to its valuable properties such as wide range of electrical conductivity, their superior flexibility and strength, But it is currently obstructed in use due to the high cost of manufacturing and the complexity of the synthesis. Furthermore, in today's world, human life is heavily influenced by greenhouse gases, and avoiding emitting gases like CO2, is almost infeasible. This thesis provides an... 

In the classical theories of plasticity, plastic deformation of material is modeled with a macro- scopic viewpoint and without considering the existing physical mechanisms at the crystal scale. However, plastic deformation stems from slip phenomena and evolution of crystalline structure. Furthermore the effects of initial texture of material on its mechanical properties, like formability, and also texture evolution of material can only be calculated by considering these physical mecha- nisms.The main purpose of this thesis is to predict forming limit diagrams of sheet metals based on crystal plasticity approach by considering the effect of initial material texture and presentation of... 

The g-C3N4/Fe2O3 nanocomposite was produced by the combustion synthesis. The product was characterized by x-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller study (BET), Ultraviolet-visible analysis (UV-vis) and photoluminescence measurement (PL). Effect of iron nitrate on stability and photocurrent density under simulated visible-light irradiation was determined. The highest photocurrent density obtained (4.25 μA/Cm2) was twelve times the pure g-C3N4. This improvement was due to a bandgap decrease, the specific surface area increase, reduction of the electron-hole recombination, and... 

Cadmium sulfide (CdS) thin films were successfully fabricated in argon atmosphere on glass slides and Single Layer Graphene(SLG)/Cu foil stack by close space sublimation technique in three different deposition temperatures. Successive Ionic Layer Adsorption and Reaction (SILAR) technique is used as a complementary technique for better and denser layers. Analysis techniques such as Grazing Incident X-ray Diffraction (GIXRD) and Scanning Electron Microscope images were used for structural study of the deposited layers. Polycrystallinity and hexagonal wurtzite structure of the thin films is confirmed. For band gap calculations and for determination of optical behavior of the layers in different... 

In this project, the aim is finding the corrosion behavior and biocompatibility of metallic biomaterials in simulated body fluids.by this study we can have a wide knowledge about the behavior and use of metallic biomaterials.in this project we use three base metals. Ti (grade 5 and grade 2), stainless steel (316L and 316) and Mg alloy(AZ91 and AZ31). the media was six physiological environment( Cigada solution, Hank solution, SBF solution, Fusayama solution, Ringer solution and Tyrod’s solution). all of these environments are related to the body fluids except Fusayama solution that is an artificial saliva and is a mouth fluid. we used polarization tests to determine the corrosion behavior... 

Although studies have shown interesting piezoelectric and dielectric properties of PZT containing composite piezoelectric ceramics, there has been no systematic investigation on the PZT-PCN, especially on the porous one.In this study, the dense ceramics of 0.8Pb (Zr1/2Ti1/2)O3–0.2Pb(Co1/3Nb2/3)O3 abbreviated to (PZTCN) systems were successfully prepared by the columbitewolframite precursor method via the mixed oxide technique. Porous PZT-PCN ceramics were prepared by burnable plastic sphere process (BURPS) technique with three types of pore forming agents (PFAs), poly vinyl chloride (PVC), stearic acid (SA), and poly methyl methacrylate (PMMA) at different weight percentages(5, 10,and 15... 

Recently, low temperature carburizing of stainless steels, especially austenitic stainless steels, have been considered by so many researchers. The improvement of tribological properties of which is so impressive so much so that such properties like hardness and wear resistance increase to manifold. In this research, low temperature carburizing was done on two kinds of precipitation hardenable stainless steels 17-4 and 13-8 Mo. After that, microstructural investigations were done on the carburized surfaces and in 5, 10, 20, 80, and 150 micrometer depths. Moreover, in each depth, in order to phase structure and tribological properties investigation, XRD and microhardness tests were done,... 

In the present study, nanocomposite of Ce-TZP/Al2O3 was synthesized via aqueous combustion synthesis. In order to investigate the effects of alumina on the morphology and the mechanical properties of this nanocomposite, four sample with 20, 40, 60 and 80 mole percent of alumina were prepared. At first, the synthesized powders were characterized with scanning electron microscope and X-ray diffraction technique. Then, in order to determine the effects of alumina mole percent on the mechanical properties of the nanocomposite, the powders were uniaxailly compacted with the press of 250 MPa followed by sintering at the temperature of 1400 °C for 4 hours. The density of the compacted powders was... 

In this study, nano-powders of copper-cobalt spinel (CuCo2O4) were fabricated by solution combustion synthesis (SCS) of Cu and Co nitrates with urea, glycine,acid citric and alanine. The method involved exothermic decomposition of viscous liquid nitrates and the fuel. Products which were synthesized by using this fuels contained less impurity constituents. Duo to low purity, other factors which have influence on synthesis process investigated and observed that pH have key role on process. X-ray diffraction (XRD) patterns gave crystal structure and the existing phases. Particle size distribution and morphology changes were studied by dynamic light scattering (DLS) and field emission scanning... 

In this study, Cu-TiC nanocomposites were produced by high energy ball milling of elemental powders and in situ formation of TiC in the copper base. Cu and 5,10,20 and 40 wt% Ti powder blend were milled for 60 h, then graphite powders were added and milling was continued for 10 h again and Finally Cu-TiC composite powders with 10.68, 20.16, 36.24 and 60.25 vol% of reinforcements (6.18, 12.2, 23.82 and 45.47 wt%) were produced. The effect of time on the solution of titanium in the copper was studied by X-Ray diffraction analysis (XRD). crystallite size and lattice strain of copper were determined 12nm and 1.04% subsequently for Cu-40wt%TiC after 60 h milling. to ensure the formation of... 

In this project alumina-zirconia-ceria nanocomposite with 80% mol alumina (0.2Ce0.1Zr0.9O2-0.8Al2O3) was produced by solution combustion synthesis method. In the mentioned method, optimal fuel with composition of 75% urea, 25% ammonium acetate, and stoichiometric amount of glycine (0.75U-0.25AA-1G) was used. Moreover, ammonium nitrate as aid combustion was added to optimal fuel. In order to calcinations, nanopowder obtained from combustion synthesis was heated to 500°C for 1 hour and kept at this temperature for 2 hours. To complete heat treatment, the nanopowder was heated to 1150°C for 2 hours and 10 min and kept at this temperature for 2 hours. Then the specimens were pressed at pressure... 

TRIP steel with good plasticity properties, has ferrite, bainite and retained austenite phases at ambient temperature. According to austenite to martensite phase transformation during plastic deformation, this grade of steel has high elongation and ultimate tensile strength, simultaneously. There are some parameters which affect the stability of retained austenite, such as: imposed strain, strain rate, temperature of deformation, grain size, weight percentage of different alloy elements and crystallographic orientation of existing phases. Mechanical properties of TRIP steels are improved by increasing stability of retained austenite. TRIP steels have been... 

In this research, the surface of multi-walled carbon nanotubes (CNTs), as template, were coated by Lead zirconate titanate (PZT) with composition of Pb(Zr0.52Ti0.48)O3 via sol-gel process. The final product is called PZT-CNT hybrid material. For functionalizing of CNTs, benzyl alcohol was used. Simultaneous thermal analysis (STA) proved that the as-derived amorphous material crystallized at 520 ˚C. Scanning Electron Microscope (SEM) images verified the deposition of a uniform coating of PZT on the surface of CNTs and proved that the functionalizing treatment was done successfully. X-ray diffraction (XRD) showed that the crystal structure of the hybrid was tetragonal perovskite.... 

In this project, synthesis of sol-gel derived Pb(Zr0.52Ti0.48)O3 nanotubes in the form of PZT-CNT hybrid, was accomplished by using multi-walled carbon nanotubes as sacrificial template. Simultaneous thermal analyses proved that the as-derived amorphous material crystallized at a significantly low temperature by a considerably low activation energy. X-ray diffraction and selected area electron diffraction patterns showed that the final crystal structure is tetragonal perovskite. Raman spectroscopy results proved that significant changes happened at the surface of carbon nanotubes which are believed to be due to coating. Electron images supported the deposition of a coating on the surfaces of... 

About 20% of total oil in the world is reserved in fractured reservoirs and there is also more than 60% of remained oil in the world in these reservoirs. But increasing recovery factor and production from this type of reservoirs was not very successful. After water flooding process most of the oil remains in the reservoir. The amount of remained oil is much more specially in fractured reservoirs. Surfactant flooding in one of the well-known enhanced oil recovery methods for reduction of interfacial tension between fluids to decrease capillary forces that cause less oil trapping and higher oil recovery. But a comprehensive and accurate understanding of the mechanism of this process and... 

After the discovery of high temperature superconductivity in (LaM)2CuO4, different type of cuprate superconductors have been synthesized. Among them, YBCO compounds (e.g. YBa2Cu3O7-δ) have drawn more attention by researchers due to some advantages such as easier conditions of synthesis high quality samples in comparison with the other cuprate superconductors. However, superconductivity properties of these compounds are very sensitive to structural imperfections; hence it is important to study the effect of the microstructure on the behavior of the compounds. The compound YBaCu2Ox (Y112) is one of these microstructures that may form in YBa2Cu3O7-δ (Y123) samples. On the... 

Due to the interaction of high power lasers with over-dense plasma high harmonics are generated. The increase in harmonics cause an increase in frequency to the level of x-ray frequency and is thus a new method for creating x-ray lasers. In this research, we seek to understand the physics of this problem . Some theories try to explain this phenomenon based on the Doppler shift caused from the reflection of the laser beam from surface of the plasma, which oscillates with relativistic velocity.some try to explain this phenomenon based on the similarity with synchrotronic emissions. In this research, the main theories on this subject are reviewed, and a modelling of the emission caused by the... 

Electrical arc discharge in ambient air, vacuum, reactive gas and other environment is an appropriate method for synthesis of different nanostructures. This method can provide stable and ultra pure nanostructures with diverse applications. In this research we focus on synthesis and analysis of titanium nitride nanoparticles in liquid nitrogen(lack of oxygen)by Electrical arc discharge . At the beginning a reactor for the electrical arc discharge process designed and implemented. Titanium nanoparticles have synthesis by this method analyzed. Several characterization techniques such as X-ray diffraction (XRD), dynamic light scattering (DLS), X-ray photo electron spectroscopy (XPS), scanning... 

In this study, synthesis structural and theoretical studies of four rhenium tricarbonyl complexes with 3-cyanobenzaldimino ethylenediamine (3CNbzen) and 2,3,6,7-tetraphenyl-1,4,5,8-tetraazaphenantherene (Ph4TAP) were investigated. The synthesized complexes were characterized by spectroscopic methods and their solid-state structure were determined by single-crystal X-ray diffraction analysis. Using single-crystal X-ray diffraction structure, the intra- and intermolecular interactions of the complexes and their dimers resulted from X-ray Cartesian coordinates were investigated. Furthermore, computational approaches were carried out to confirm the existence of the intra- and intermolecular...