Sharif Digital Repository

Most broadcast stations insert their logos to claim video content ownership and/or for business purposes.This process reduces picture quality in the logo region and also causes visual discomfort to viewers. Logo detection has a variety of applications; such as automatic TV commercial removal, broadcast surveillance, and video content understanding. Video logos can be considered as a form of visible watermark. Stations may also overlay their logos over the original logo when rebroadcasting a program produced by another station. Also, most comapnies keep a giant archive of their broadcasted programs which are going to be used in their future programs. Here, we have presented an efficient... 

The main purpose of the thesis is Digital image Processing using the sparsity of image. The issue could be described in two ways. First is reconstruction of missed blocks of an image based on the sparsity of image in the transform domain and second is impulsive noise removal using the sparsity of noise in the spatial domain. In the first approach we will review Guleryuz method and simulate and analyze it. In the second approach, two new methods named RDE and Knockout will be introduced. These methods try two remove the impulsive noise of an image using its sparseness. RDE method is a development of conventional methods, but Knockout has a completely new idea. We will show that Knockout is... 

Well worn gas turbine blade made of Nickel based superalloy, IN738LC was remelted due to remove inclusion and use it in casting process of new blade after microstrucrure investigation in neutral atmosphere and vacuum. The composition of slags for removing inclusions used for this practice were 70CaF2-20CaO-10Al2O3 and 55CaO-45Al2O3. The microstructural characterization involved use both optical as well as electron microscope including application of EDS technique for denoted the type of carbides and inclusion investigation. Chemical composition was determined by despersive spectroscopy method. The changing in main elements were reported too low. Number of inclusions were decreased in the... 

Membrane bioreactors (MBRs) which are commonly understood as the combination of membrane filtration and biological treatment using activated sludge have several advantages, but membrane fouling reduces the membrane efficiency, permeability and lifetime. An alternative is replacing a moving bed biofilm reactor (MBBR) with the activated sludge system which may reduce the effect of membrane fouling. The sludge produced in MBBRs has poor settling characteristics, therefore, their efficiency is limited by the sedimentation tank performance and they require a larger settling surface. The combination of moving bed biofilm reactors and membrane bioreactors can compensate for the drawbacks of both of... 

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... 

With the current demands in alternative methods of energy production and increased utilization of existing energy sources, microbial fuel cells have become an important field of research. In a microbial fuel cell, organic and inorganic compounds can be oxidized by microbial catabolism at the anode to generate direct electricity. A kind of microbial fuel cell (MFC) is sediment microbial fuel cell (SMFC) consists of an anode electrode embedded in the anaerobic sediment and a cathode electrode suspended in the overlying aerobic water. microorganisms produce electrons by oxidation of organic or inorganic compounds in the sediment at anode electrode, while oxygen is reduced in the water by... 

Mesoporous silica nanoparticles (MSNP) have attracted lots of attentions because of their particular characteristics. Physical characteristics such as structure, morphology, porosity, and size of these nanoparticles have strong impact on their function and it can be conceived a wide range of applications for them by manipulating these characteristics. In this research, monodispersed MSNPs with a controllable size in the range of 50-130 nm and pore size in the range of 4-24 nm were synthesized and positively functionalized in order to develop a carrier for the delivery of nucleic acids (siRNA and pDNA). The MSNPs were synthesized by the template removing method.In this method, sodium... 

In the present study, effects of Post Aeration stage on moving bed biofilm reactor (MBBR) sludge and effluent quality was investigated by simulated wastewater. Reactors Volume were 3.2 and 5.9 Liter and their filling-fraction were 53% and 29%, respectively. All tests were done at 2.5 and 4.6 volume fraction, in which organic loading rates (OLR) were 2, 4, 6 g/L.d and Hydraulic retention times (HRT) were 3 and 6 hours. Increasing in HRT results in bioreactor efficiency improvement, the most efficiency values were found 81% and 84% for MBBR and MBBR-PA respectively at HRT of 6 hours and 53% filling-fraction. The greatest effect of post aeration on organic removal rate was obtained at HRT of 3... 

In the present study , operation of a laboratory scale sequencing batch reactor (SBR) was evaluated to treatment of synthetic wastewaters containing ethylene glycol. Studies carried out with a plexiglass bioreactor whith effective volume of 18 lit.Aeration was supplied via two air diffusers that set at the bottom of the reactor. Synthestic wastewater containing ethylene glycol and molasses as carbon source and other nutrient such as diammonium hydrogen phosphate as phosphor source and urea as nitrogen source for biological activities was composed at the laboratory. To optimization of this reactor three parameters – aeration time, chemical oxygen demand and sudden change in arganic loading... 

Uranium is the most important element in the nuclear fuel cycle. Recovery of uranium from waste produced at every stage of the fuel cycle is not only economically important, but also environmentally important. In the production phase of uranium hexafluoride, certain amount of solid waste is produced in the bottom of the fluorination reactor. In order to extract the uranium from this waste, we have to eliminate the fluorine contained in the waste. This is because the fluorine forms strong complex with uranyl ions during the extraction process, and prevents from efficient extraction of uranium. In the current thesis؛ first, we examined the characteristics of the waste ... 

Nowadays with the extension of industry and factories as well as different kinds of plants, a wide range of pollution and circumference hazardous has been entered to the people`s life. Industrial wastewater has been always a threat for health of our environment and efforts for reducing its dangerous effects are still under studies. Dairy wastewater is one of the main branches of food industrial pollutions and it has been studied in this specific project. The goal was to reduce the Chemical Oxygen Demands (COD) of dairy wastewater with oxidation of Titanium Dioxide Nanophotocatalyst oxidation under UV irradiation. Among the various methods for synthesizing of this Nanophotocatalyst, the... 

Permanent Downhole Gauge (PDG) has been employed since 1990s to acquire more information and better access to well and control production. PDG provides huge amount of pressure transient data during well test operation and production. However, such data are encountering with various noise and outliers. The noise and outliers can cause misleading and misinterpretation results. Therefore, denoising and outlier removal are two imperative steps before pressure transient analysis. The conventional denoising methods are mostly based on wavelet thresholding methods that preserve mean of data and have good performance when noise distribution is Gaussian distribution. However, noise distribution... 

Regarding decreasing resources of fossil fuels and their increasing costs in addition to their environmental pollutions, today, producing bio fuels from wastes such as lignocellulosic materials is of great interest. A fundamental stage in conversion of lignocellulosic materials into bio fuels, such as bio ethanol, is the enzymatic hydrolysis of these materials to produce reducing sugars. Researches have shown high costs of this stage. Optimization of enzymatic hydrolysisconditions is a major step in economization of this process.In this work corn hull is used to produce glucose. Corn hull is a kind of lignocellulosic material that due to high carbohydrate content is used as substrate. Our... 

Nuclear energy is one of the most important sources of energy from the economical point of view and also in terms of cleanliness and safety. Hence, strategically, uranium is one of the most basic elements of the earth and nowadays, the importance of this element is more marked due to the nuclear industry developement. Therefore, uranium recovery from the wastes generated during nuclear fuel production in Isfahan’s uranium conversion plant- in which yellow cake is converted to uranium hexafluoride- is quite pivotal. In this experimental research, we have to remove Fluoride from waste after dissolution by several methods like precipitation. After that uranium is extracted from the sludge of... 

Electrocoagulation is one of the new methods for water and wastewater treatment that is carried out by electrical current. This method is easily applicable to a variety of wastewater. it is highly efficient in organic matter removal and other toxic are and dangerous pollutants.
This study dealt with diesel and COD removal by Electrocoagulation method. Energy consumption, electricity consumption, and the amount of sludge produced by this method was evaluated. Experiments were conducted in a 2 L reactor, consisting aluminum and iron electrodes.The distance between anode and cathode was 5 cm. To evaluate the efficiency of electrocoagulation method, parameters including: pH, time,... 

In this project, cellulose acetate butyrate (CAB) nanofibrous membranes in order to separate the contaminants of an industrial wastewater were prepared. Electrospinning process that is an effective method to fabricate nanofibers was used to prepare the membranes. Since various parameters affect this process and fibers morphology, optimization of these parameters is necessary for preparation of improved membranes. So the effect of parameters of solvent system, polymer concentration, applied voltage, distance between the tip of needle and collector, and rotational speed of collector on morphology and diameter of the nanofibers was investigated. Scanning electron microscopy (SEM) and image... 

Epilepsy is a neurological disorder whose prevalence is estimated to be 1% of the world population. Electroencephalogram (EEG) is one of the best and convenient non-invasive tools used in diagnosis and analysis of this disease. Epileptic components extracted from EEG recordings are widely used in neuroscience in the diagnosis analysis like epilepsy source localization. However, epileptic components are often contaminated and covered with artifacts of physiological origin (baseline, EMG, ECG, EOG, etc.) or instrument noises (power supply, electrode, etc.). So, preprocessing and denoising is necessary for precise analysis of epilepsy EEG recording. Heretofore, several methods have been... 

In this thesis, at first, we study the active inductors have been reported in the literature. Then by choosing one of them and investigating its advantages and disadvantages, we changed the structure in a way to solve its problems. On the way by using this active inductor and a negative capacitor, we designed an oscillator in 1.5 GHz frequency that has -106 dBc/Hz phase noise at 1MHz offset and its FOM value is 160 dBc. Also this oscillator is capable of frequency tunability of oscillation from 500 MHz to 2.2 GHz. In this spectrum the phase noise is changing between -100 dBc/Hz and -110 dBc/Hz. In the second part, in the aim of improvement of phase noise of oscillator structures based on... 

In this research, a review on fluoride adsorption revealed that the modification of the adsorber surface with ions like Ca2+ results in great enhancement of the fluoride adsorption. It seems that the enhancement in fluoride adsorption by the modified adsorber, is mainly due to the selective chemical binding of the fluoride ion with the surface-bound ion (Ca2+), regardless of the base material itself. In order to confirm this hypothesis, two different adsorber materials namely, γ-alumina (a material, conventionally used for fluoride removal from water and wastewater) and Micro-silica (a mineral with small adsorption capacity for fluoride) were selected for further study. It was found that the...