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Numerical Study of Oxygen Enrichment on NO Pollution Spread in an Ignition Chamber
, M.Sc. Thesis Sharif University of Technology ; Kazemzadeh Hannani, Siamak (Supervisor)
Abstract
In the present study, a 3D combustion chamber was simulated using FLUENT6.32. The objectives were to obtain detailed information on the combustion characteristics and NO formation in the furnace, and also to examine the effect of Oxygen enrichment on the combustion process. The combustion chamber has internal dimensions of 60 cm wide, 90 cm high and 190 cm long. The fuel pipe diameter is 1.25 cm and the air pipe diameter is 3.5 cm. The 3-D Reynolds Averaged Navier Stokes (RANS) equations together with standard k-ε turbulence model are solved by Fluent 6.3. Air/fuel flow rate ratio is varied as 1.3, 3.2 and 5.1 and the oxygen enriched flow rates are 28, 54, 68 lit/min. NO emission was...
Oxygen Barrier Improvement of the BOPP Films in Food Industry
, Ph.D. Dissertation Sharif University of Technology ; Bagheri, Reza (Supervisor)
Abstract
One of the most popular methods in order to protect foods is to package using various materials. By this act, the shelf life of the packaged foods may range from a few days to more than a year. Multiple types of plastics are being used as materials for packaging food, including polyolefin, polyester, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, and ethylene vinyl alcohol. Although more than 30 types of plastics have been used as packaging materials, polyolefin and polyesters are the most common. Biaxially Oriented Polypropylene (BOPP) is a polypropylene film that has been stretched in both the machine and cross directions. BOPP film has become one of the most popular...
Control of Eutrophication in Anzali Wetland by Artificial Floating Islands
,
M.Sc. Thesis
Sharif University of Technology
;
Abrishamchi, Ahmad
(Supervisor)
Abstract
Anzali wetland, in the Caspian Sea, northern Iranian province of Gilan, ranges from fresh near the tributary streams to brackish near the mouth into the harbor and the sea. Anzali wetland has faced with the serious levels of eutrophication because on the other hand, the lagoon has decreased in size during current century, to less than a quarter of its former extent and on the other hand, this wetland is faced with entering a huge amount of nutrient elements due to human activities in its watershed. Discharge of industrial wastewater, animal wastes, timber harvesting and the most important entering, rice farms irrigated wastewater are of the considerable causes of eutrophication in wetland....
Synthesis of N-Doped Graphene-Transition Metal Oxide Nanocomposites and Their Applications in Electrocatalytic Oxygen Evolution Reactions
, Ph.D. Dissertation Sharif University of Technology ; Shahrokhian Dehkordi, Saeed (Supervisor) ; Irajizad, Azam (Supervisor)
Abstract
Oxygen gas has many applications and is used in respiration, welding, methanol production, steel industry, rocket fuel and most importantly fuel cells. Today, due to the environmental pollution caused by fossil fuels, the use of clean energy production methods such as fuel cells has received much attention. In hydrogen fuel cells, electrical energy is generated using oxygen and hydrogen gases through an electrochemical process. One of the common methods of producing these gases is electrolysis of water in which the kinetics of anodic reaction (oxygen evolution) have led to many researches in the field of improving metal and non - metal electrocatalysts, especially based on carbon...
Synthesis of Titania Coated Upconversion Nanoparticles with the Capability of Being Utilized in Photodynamic Therapy Under the Near-Infrared Radiation
, Ph.D. Dissertation Sharif University of Technology ; Madaaah Hosseini, Hamid Reza (Supervisor) ; Soleimani, Masoud (Supervisor) ; Mohajerani, Ezeddin (Co-Supervisor)
Abstract
Development of novel photosensitizers and photocatalysts with near-infrared (NIR) light activity and efficient sunlight harvesting is of great importance in photodynamic therapy and environmental remediation. In this work, very small (20 nm) upconverter SrF2:Yb,Tm@CaF2:Yb@Fluorine-doped TiO2 heteronanoparticles (denoted as UCNPs@TiO2) with strong UV-blue emission and wide-spectrum photocatalytic activity were synthesized via a facile three-step hydrothermal method, for the first time. The SrF2: Yb,Tm upconverter nanoparticles were produced as the light-emitting core, epitaxially-grown CaF2 : Yb as the middle shell to enhance the Upconversion luminescence efficiency and TiO2 as the...
Impermeability of Oxygen in Passive/Active Polyethylene Nanocomposite Films
, Ph.D. Dissertation Sharif University of Technology ; Bagheri, Reza (Supervisor) ; Shojaei, Akbar (Supervisor)
Abstract
In this study, polyethylene films made of LDPE / LLPE / reinforced with mechanical barrier of clay and reactant of iron nanoparticles were made in their optimal combination and necessary improvements were made on them. Investigations show that, independent of volume fraction, the addition of spherical nanoparticles does not have much effect on reducing the polymer matrix’s permeability. In nanocomposites containing cylindrical particles, for considerable reduction of the permeability, over 20 volume percent of nanoparticles it is required, while in platelet nanoparticles, less than 10% vol is sufficient. In clays with modifier concentration above the cation exchange capacity, there is less...
Numerical Investigation of Kerosene Spray Combustion with Preheated and Diluted Airflow
, M.Sc. Thesis Sharif University of Technology ; Mardani, Amir (Supervisor)
Abstract
MILD combustion can be a promising technology to prevent global warming. In this study, for the first time, the numerical simulation of MILD spray combustion of kerosene fuel with preheated and diluted air has been conducted in the faculty's SMSTR test stand. The modeling framework is based on the Reynolds averaged Navier-Stokes turbulence approach and the standard k–ε model, the DPM discrete phase model, and the EDC combustion model, using the skeletal chemical mechanism of Jet A POSF10325 kerosene with the air and droplet being tracked in Lagrangian coordinates. The simulation is done in a steady state and by an axisymmetric method, and the effects of inlet oxygen concentration, inlet air...
Numerical Study of Combustion of H2-O2 Cryogenic Propellant under Supercritical Condition
, M.Sc. Thesis Sharif University of Technology ; Mardani, Amir (Supervisor)
Abstract
In order to improve performance and optimize design of high pressure combustion devices such as liquid rocket engine, gas turbine engine, and diesel engine there is a need for comprehensive understanding of injection, mixing and combustion in supercritical condition. Under this condition chamber pressure is higher than critical pressure of fuel and oxidizer. The characteristic of supercritical condition, include changing thermophysical properties such as density, CP, and compressibility factor. Therefore under this condition ideal state equation cannot correctly predict the mentioned properties. These characteristics make supercritical combustion different from other combustion regimes....
Modeling of Biological Matter Cycling in Shallow Lake by System Dynamic Method
, M.Sc. Thesis Sharif University of Technology ; Abrishamchi, Ahmad (Supervisor)
Abstract
Modeling of water quality in shallow lake is the goal of this roject.Matters cycling in environment will be explained. The dissolved Oxygen will be assigned the most important factor in water quality. The phytoplankton Growth rate and fatality rate will be modeled By LOTKAVOLTERRA equations. The nitrification by nitrifying bacteria and Michael Menton equations will be explained. Modeling will be executed By System Dynamic which feedbacks are the most com ponents of it.The model will be built with equations and coefficients in literatures and this model run by VENSIM®software. We will assure by some extreme condition tests about the structure of the model and finally we will make a...
Optimization of the Pulp and Paper Mill Wastewater Treatment System from Recycling with the Aim of Reducing COD by Conducting a Laboratory Pilot Plant
, M.Sc. Thesis Sharif University of Technology ; Raie, Mohammad (Supervisor)
Abstract
Paper and cardboard waste pulping consume large volumes of water, so the discharge of this effluent without proper treatment can have far-reaching environmental consequences. The color and variable COD concentration of wastewater in this industry make treating this wastewater complicated. Therefore, this study aims to reduce the COD of the wastewater treatment plant of a pulp and paper mill under different laboratory conditions to achieve environmental standards in Iran.In this study, coagulation-flocculation and the Fenton process on the wastewater entering the treatment plant were investigated first. It was found that coagulation and flocculation by 750-1250 ppm of alum coagulant and ten...
Evaluation of Vermifilter Efficiency in Petroleum Wastewater Treatment (BTEX)
, M.Sc. Thesis Sharif University of Technology ; Torkian, Ayub (Supervisor) ; Mirzai, Mohammad (Supervisor)
Abstract
The aim of this thesis was to find the optimum retention time for treatment of synthetic petroleum wastewater by a wastewater treatment system made with a bucket, mineral material and earthworms residing in a vermibed. In order to make the desired flow happen, height difference was utilized. The polluting substance used for making wastewater was BTEX. As the wastewater was synthetic, the concentration was also a variable. The ultimate soluble concentration was 3200 mg/l and more concentrations were not tested. Parameters such as number of worms, worm’s growth rate and their distribution pattern, humidity amount and distribution and worm’s acclimatization time during organic loading shock...
Evaluation of Water Quality of Anzali Lagoon by Developing a Numerical Model
, M.Sc. Thesis Sharif University of Technology ; Safaie, Ammar (Supervisor)
Abstract
Wetlands are valuable ecosystems that have a wide variety of functions to protect biodiversity, natural, economic and social values. Hydrological changes and nutrient enrichment, resulting from population growth, economic development and climate change are threatening the wetlands. Recently, assessing spatial and temporal variations of water quality has become an important aspect of the physical and chemical characterization of aquatic environments. Anzali wetland is one of the international wetlands in Iran, located in the southern part of the Caspian Sea in Gilan province. This wetland has been exposed to many pollution sources including agricultural, industrial, and municipal wastewater...
Retriving Grey Wastrwater by Biological Treatment and Aerobic Submerged Filters and UF Membranes
, M.Sc. Thesis Sharif University of Technology ; Borghei, Mehdi (Supervisor)
Abstract
Nowadays with the increasing population of the world and constraint or even water shortages, necessity of reuse the effluent of the treatment plants is further increased whearas the grey wastewater (wastewater related to bathroom, dishwasher and laundry). They are part of the household wastewater.quantity ranging from 65% to 75% sewage produced in the house is grey water. In many developed countries of the world the grey wastewater treatment and its use in non-potable wastewater like irrigation, car washing and toilet siphoning are commonplace. This wastewater is lower in COD and BOD than conventional wastewater but it still needs to be refined. There are varios methods including biological...
Treatment of Greywater Using Chemical Processes and UF Membrane Filtration
, M.Sc. Thesis Sharif University of Technology ; Borghei, Mehdi (Supervisor)
Abstract
Greywater accounts for about 70% of household consumption and can be returned to the consumption cycle if a sustainable system is built in residential areas and the treated water can be used for irrigation, flash tank filling, and even aquifer fillings. The purpose of this study was to establish a sustainable method in small treatment plants that could sufficiently recover the water used in households. In this study, chemical ways of wastewater treatment, as well as membrane filtrations, were investigated to reduce greywater pollution. The results show that the coagulants alone can remove 80% of COD. Membranes can also reduce COD by up to 83%. In addition, the best removal efficiency using...
Wastewater Treatment by Integrated MBBR-MBR and BF-MBR Methods to Increase Performance and Decrease Membrane Fouling
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Manoucherhr (Supervisor)
Abstract
The effect of the combination of MBR and MBBR systems to enhance the efficiency of water treatment plants has been studied. In this study, by embedding a UASB reactor in the presence of packing, as anoxic, two MBBR reactors as a single aerobic treatment and a MBR reactor once with and once without packing as the final purification tried to remove pollutants from artificial drainage and extend the life of the membrane system is designed to convey the wastewater treatment and irrigation is its quality standards functionality and the quality of its wastewater treatment standards for agricultural irrigation. Studied pollutants include COD, ammonia, nitrate, nitrite and phosphate. membrane...
Optimization of Fluidized Bed Bioreactor (FBBR) for Wastewater Treatment by Pumice Stone
, M.Sc. Thesis Sharif University of Technology ; Borgheei, Mahdi (Supervisor) ; Pak, Ali (Supervisor)Performance Evaluation of Membrane Bioreactors in Treating Municipal Wastewater
, M.Sc. Thesis Sharif University of Technology ; Torkian, Ayoub (Supervisor)
Abstract
Membrane bioreactors can replace the activated sludge process and the final clarification step in municipal wastewater treatment. The combination of bioreactor and crossflow microfiltration allows for a high chemical oxygen demand (COD) reduction of synthetic wastewater. In this study, experimental data from a laboratory scale membrane bioreactor are presented. In order to investigate the influence of various operating parameters such as hydraulic retention time (HRT), biomass concentration and organic loading rate on organic pollutant removal, the pilot scale submerged membrane bioreactor (SMBR) with a Polyvinylidene Fluoride (PVDF) hollow fiber membrane module was conducted using synthetic...
Acceleration of Anaerobic Stabilization of Organic Solid Waste &Treatment of Following Sewage by a Biologic Tower
, M.Sc. Thesis Sharif University of Technology ; Hashemian, Jamaleddin (Supervisor) ; Nazari Alavi, Alireza (Supervisor)
Abstract
In this project, function of anaerobic digestion of organic waste in liquid phase and treating the following sewage in biologic tower(trickling filter) has been investigated in an experimental process. Solid waste were supplied from sharif university restaurant and after weighting and classification is added to tanks which filled by 40% sludge and 60% water. For controlling the function of biologic tower, a control reactor were used. Retention time for digestion of solid waste is 40 day. First solid loading was 500g and 75g organic waste in main & control reactor equal to 5(kg solid waste)/( m^3.reactor.day) 1.3(kg TS)/( m^3.reactor.day) and were doubled in second loading. It seems that...
Numerical Simulation of Glucose Metabolism and Hepatocyte Viability within a Microfluidic
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
The advent of microfluidics as suitable environments for culturing cells is associated with some challenges such as shear stresses applied on the cells. In fact, hepatocytes lose their function as exposed to high shear stresses similar to other cell types. Moreover, among all factors needed for cell viability, feeding hepatocytes with adequate oxygen is of great importance due to their high demand for oxygen compared the other cells. In this thesis, different types of cultures including 2D and 3D has been used in order that shear stresses would be in allowed range and provision of hepatocytes with sufficient oxygen concentrations has been ensured as well. In addition to supplying hepatocytes...
Numerical Simulation of Shaking Bioreactors for Cell Culture
,
M.Sc. Thesis
Sharif University of Technology
;
Saidi, Mohammad Said
(Supervisor)
Abstract
A bioreactor can refer to any device or system constructed on engineering basis and has an active biological medium. This medium includes aerobic and non-aerobic reactions in which organisms and the theire produced substances have the main role. One of the applications of bioreactors is to provide an appropriate medium for animal and plant cell culture and growth. Nowadays many biological processes in high volume scales are carried out in stirred tank bioreactors. In these bioreactors oxygen transfer is usually increased by increasing turbulence which is necessary for mixing nutrients and keeping the homogeneity of the medium. However, there are some limitations for increasing the stirring...