Sharif Digital Repository

Cyanide ion is one of the materials used in various industries related to metallurgy, the release of which in the environment causes water, air and soil pollution. Numerous researchers have used different methods to remove this pollutant from the environment. Comparing these methods with each other, photocatalytic processes have attracted a lot of attention due to the use of sunlight as a sustainable energy source, good efficiency, low cost, etc. Therefore, in the present study, first the heat-treated graphite carbon-nitride photocatalyst was synthesized and then characterized by X-ray diffraction (XRD) tests, infrared spectroscopy (FT-IR), scattered reflectance spectroscopy (DRS),... 

The main purpose of this project is synthesis of the silica nano-sheets by means of microfluidic techniques. Continuous process, precise control of reaction condition, and higher production rate can be considered as main pros of silica nano-sheets synthesized by microfluidic platforms. General method can be explain as follow: first two oleic and aqueous phase are injected to the microfluidic system, then oleic phase breaks down in aqueous phase drop-wisely and by performing sol-gel reaction on the oil-water interface a silica crust is made on oil droplets. Eventually, oil droplets are left the system and broken down and silica nano-sheets are made. FESEM and microscopic images of... 

In this study, linear polarization resistance (LPR) of cathodic pulse electrodeposited graphene- Nickel-Molybdenum coating is optimized by design of experiments approach (central composite design). Applied current density (i), cathodic pulse durations (Ton) and total electrodeposition time (Ttotal) are selected as the substantial factors. The best prediction model proposes a definitive linear relation without any significant interaction of the LPR by analysis of variance. The best value of LPR is achieved equal to 1406KΩ.cm2, obtaining at i of 137.5 A/cm2, Ton of 45.5 ms and Ttotal equal to 315 s. Polarization test is carried out to determine corrosion behavior of the coating. It shows... 

Sulfur compounds are very undesirable and result in Corrosion in metal equipment, air pollutions and poisoning of refinery Catalysts such as reforming Catalyst. Therefore, application of Hydrodesulfurization (HDS) process in order to decrease the amount of sulfur in petroleum cuts has a great importance. HDS process is the most usual and efficientmethod for sulfur removal. In this method sulfur compounds at vigorous operating conditions such as high temperature and pressure in the presence of catalyst react with hydrogen and produce hydrogen disulfide and hydrocarbon. Sulfided Co–Mo catalysts are widely used in this process.
The aim of this study is to prepare and improve CoMo/γ-Al2O3... 

Permanent magnets play an essential role in the structure of the electric motor, but due to limited resources, many efforts have been made to meet the need for them. One of the most important types of non-permanent electric motors is reluctance motors. Despite their antiquity in design, torque ripples have led to the limited use of reluctance motors, but advances in science have made it possible to control these ripples.As a result of the major advantages such as low manufacturing costs, high efficiency, and uncomplicated structure, these motors have been the subject of many researches. One way to eliminate the problem of torque ripples is to increase the number of teeth, but in the common... 

In this thesis, the mechanical properties of collagen hydrogels were characterized using Finite Element method and the collagen content effect on the mechanical properties of hydrogels were investigated. Hydrogels samples with different collagen content were assessed which caused diverse mechanical behaviors. Due to the nonlinear behavior of hydrogels, using numerical methods and simulation softwars can be helpful to determine the mechanical properties of these material and save agreat deal of time. Finite Viscoelaticity theory was exploited for a UMAT Subroutine in Abaqus and an special Starin Energy Function was selected to extract the formulations. The agreement between simulation results... 

Billions of dollars are spent annually repairing broken or damaged pipes and fittings. The bulk of these costs relate to traditional methods used to repair and rehabilitate pipelines, such as replacing the desired part or using steel sleeves on the damaged part, this operation requires shutting down the service, which is costly. Uncertainty about the reliability and durability of existing repair methods has created the need to develop and provide a fast, safe, economical and safe way to repair pipelines and fittings. This need has been met by using the capabilities and potentials of composites, and composites have replaced traditional methods that reduce costs and time. In this project, the... 

Due to well mechanical properties and high resistance to environmental conditions, metal pipes are used to transport oil and gas products, water and sewage, as well as hydraulic systems in aircraft or aerospace systems. Therefore, maintenance of oil and gas transmission lines in energy-related industries and pressurized tanks in the aviation industry has always been a concern of engineers. Due to the problems of old methods for repairing damaged pipelines or aerial structures, it seems necessary to provide new, safe and cheap methods for repairing them. Various engineering standards for pipelines and their repairs have been presented so far which have analytical solutions to determine the... 

The search for sustainable and clean energy sources to replace fossil fuels has become one of the most important scientific and technological challenges today due to the threat of fossil fuel shortages and environmental pollution. Therefore, the need for clean energy production and storage resources, including supercapacitors, has increased day by day. Today, supercapacitors have been considered suitable for energy storage due to their high-power density, appropriate energy density, long cycle life, and high safety. The aim of the present study was to obtain activated carbon fabric as electrode material in electrochemical energy storage applications and specifically supercapacitors. The... 

Additive manufacturing (AM), also known as Rapid prototyping or D printing, is a new technology for the manufacturing of the physical parts through an additive manner. In the AM process, the orientation pattern of the part is one of the most important factors that significantly affects the product properties such as the build time, the surface roughness, the mechanical strength, the wrinkling, and the amount of support material. The build time and the surface roughness are the more imperative criteria than others that can be considered to find the optimum orientation of parts. In this research, Two method is used to optimize part build orientation (PBO). In the first method a new combined... 

As nuclear energy continues to be used as a useful energy resource, waste management, especially management of high-level nuclear waste (HLW), will always be a major concern, as the future generations should not be deprived of the valuable benefits of this energy. Vitrification of liquid high-level radioactive waste (HLW) has received greater attention, worldwide, than any other high-level waste solidification process. The high solubility of HLW in borosilicate glass, the controllable temperature of this type of glass and its low leaching rate in repository environment, have introduced borosilicate glass as a suitable host for HLW immobilization. In this project, the immobilization of the... 

In this study, the effect of iron ore concentrate morphology on green pellet quality was studied. In order to produce concentrate with different morphology using ball mill, ball charge (20-40 %V), grinding time (30-50 min) and ball distribution (15 mm, 23 mm, 15+23 mm) was varied. It was deduced that increasing grinding time and ball charge would result in reduction of D80 but would increase Blaine number. The interaction parameters of ball distribution-grinding time and ball distribution-ball charge had significant effect on Blaine and D80. It was also observed that mixed level of ball distribution would lead to higher Blaine numbers. The equation obtained by CCD was verified by the...