Sharif Digital Repository

In this thesis, adsorption of Carbon monoxide and Hydrogen on graphene, by DFT calculation has been studied. Also effect of strain on some electrical properties, such as band structure, electrical conductivity and Density of states, for pristine graphene and adsorption CO and H2 on it has been probed. This results show that with strain up to 12% on pristine graphene , we won’t have any band gap on Fermi surface and energy adsorption for Carbon monoxide on strained graphene (up 12%) increase up 400 per cent. Also for strained graphene (12%) on Carbon monoxide adsorption condition we will have energy band gap almost a few electron volt on Fermi surface. In general this results express... 

In this work, we have tried to synthesize, recognize and evaluate the performance of a composite ceramic membrane to purify hydrogen and obtain high H2 separation values from other gases such as methane, carbon dioxide and nitrogen at high operating temperatures (837- 1073 K). The membrane was prepared by modification of a tubular alpha- alumina support with a series of gamma- alumina layers using sol- gel method. The membrane was then covered with a Nano-composite silica- alumina layer using CVD method. The thickness of this layer is estimated to be around 80- 100 nm and with a completely dense structure. EDX, XRD, DLS, BET and mercury porosietery analysis plus SEM and FESEM images were... 

The idea of improving performance of internal combustion engines has always been important for researchers and manufacturers. In recent decades, due to limited resources of fossil fuels and introduction of vehicle emission regulations, researchers have undertaken more efforts to achieve goals such as increased horsepower, reduced fuel consumption and pollutant emissions reductions. Homogeneous charge compression ignition engine is a modern and efficient design that has attracted attention of many researchers. In[[ these engines, homogenous mixture of fuel and air enters into the combustion chamber and with a mechanism of self ignition, produces more power and has less fuel consumption... 

The purpose of this project is modeling and solving equation of an open cycle system based on MHD generator in order to achiving geometrical properties of generator shuch as length and cross sections of channel and extractable electrical power. In this work hydrogen is used as initial fuel and it’s combustion product near oxygen as working fluid in an open cycle system concluding of combustion chamber, convergence nozzle, farady generator with separated electrod’s and constant mach number and also diffuser. Motion of fluid is considered one dimentional and direction of magnetic field with magnitude of 2 tesla is assumed to be perpendicular to motion and electrical current directs. For... 

The purpose of this project is the synthesis and characterization of a group of phenolic amino acidic derivatives that are studied in both solid phases as well as their solutions. For this, new phenol derivatives of serin and isoleucine amino acids were synthesized and characterized by 1H NMR , 13C NMR, IR spectroscopy as well as elemental analysis. These ligands were utilized to prepare LSF perovskite membrane. According to their XRD patterns, it was concluded that the powdered precursor prepared by serin derivative has shown better qualification and less intermediate phase in the synthesized perovskite membrane similar to the sample prepared by applying EDTA. Furthermore, in the previous... 

Generally, the concept of producing ‘spare parts’ of the body for replacement of damaged or lost organs lies at the core of the varied biotechnological practices referred as tissue engineering. Tissue engineering is an interdisciplinary field that incorporates principles of engineering with the life sciences. Tissue engineering is based on three principle; cells, scaffolds for cells expansion, attachment as an environment like ECM and growth factors. These things together can help tissue engineers to provide microenvironments which are suitable for special cells. The most important thing in this kind of works is the ability to simulate environment for cells the same as body. According to the... 

Using microbial electrolysis cells (MEC) for hydrogen production has been considered in recent years. So far, synthetic wastewaters containing substances such as glucose and acetate have been mainly used in MECs and industrial wastewaters have not been widely studied. Food industry wastewater is a suitable choice for application in microbial electrolysis cell due to its biodegradable materials. In present research, dairy wastewater and sludge collected from UASB reactor of Iran Dairy Industries company, Tehran were initially used in a dual chamber microbial fuel cell until a stable voltage was generated .Afterward, the system was converted to a MEC applying a predetermined voltage. The... 

In this project dynamic effect of changes in gas turbine load on power plant, reforming and Co2 capture section is investigate. The reason for study of effects change of gas turbine load is that gas turbine determines the performance of the other parts in combined cycle including gas cycle and change of gas turbine load can alter the load and the performance of other parts in the power plant and in other process such as production of synthesis gas and carbon dioxide separation unit. One Autothermal reactor and eight sewgs reactor are utilized to produce gas turbine fuel which is mainly consist of Hydrogen. this part of thesis is to be implemented in the gPROMS from process system enterprise... 

So far, many activities have been done in regarding to decrease vehicles' pollution in the international level that the electric vehicles manufacture has been emphasized in recent years. According to these issues and need to decrease air and environment pollution, the use of fuel cell as a source of power generation can have a specific effect on decreasing this pollution. In our country, according to high statistics of manufacturing and offering vehicle particularly the vehicles with high pollution, there is a need to invest in the field of creating renewable (clean) energy production systems. Regarding to decrease environment pollution and according to the importance of fuel cell's... 

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... 

Dwindling fossil fuel reserves with attendant rising crude oil price and the relatively rapid growth in global population have made the search for sustainable energy supply more imperative. Among the various renewable resources, biomass has attract much more attention. Glycerol as the major by-product of the biodiesel production process, can be converted to hydrogen. One of the methods for converting glycerol to hydrogen is aqueous phase reforming (APR). In the current research, glycerol aqueous phase reforming is modeled and then simulated with MATLAB software. The reactor diameter is 5 mm and its length is 20 cm and reactor operated at 250℃ and 50 bar. Glycerol conversion obtained is... 

In this thesis, a novel graphene oxide (GO)/sodium alginate (SA)/polyacrylamide (PAM) ternary nanocomposite hydrogel with excellent mechanical performance has been fabricated through freeradical polymerization of acrylamide (AAm) and SA in the presence of GO in an aqueous system followed with ionically crosslinking of calcium ions. Physical and chemical characteristics of the composite were investigated by Fourier transform infrared spectroscopy and scanning electron microscopy. The swelling behaviors of the composite hydrogels were investigated under varying conditions of time and pH. The optimized swelling capacity in standard conditions was found to be 1711% per gram of the hydrogel. The... 

The purpose of this study was to investigate experimentally and modeling the process of gasification with supercritical water using waste motor oil. The effect of four important and influential parameters on the process, Temperature (350-450° C), Reaction time (15-45 minutes), Oil-to-Water volume ratio (0.2-0.4) and type of catalyst Consumption (Ni- NaOH- Na2CO3) was evaluated. Experimental experiments were designed and performed on the Design Expert software. The experimental results showed that the purity of hydrogen in the gas stream is more dependent on the temperature parameter and the higher purity is obtained with increasing temperature. Subsequently, as the oil concentration... 

Many researchers believe that the production of knowledge is a cumulative process based on past learning, and on the other hand, deepening in a specialized knowledge causes fundamental changes in that field. so to justify the existing relationships, the concept of knowledge spillover is taken into consideration. Knowledge spillover means that technologies can benefit from knowledge originating in other technologies. Our goal in this research is to identify the mechanisms and type of knowledge that can affect the flow between different industries and countries. With the increasing need of the countries of the world for energy and the environmental hazards of fossil energies, an important...