Sharif Digital Repository

In this research, absorption and oxidation catalytic scenarios were examined using previous studies in the field of SO2 removal. Nanostructures zeolite 13X, 5A zeolite, gamma alumina and activated carbon were purchased, then structure, function and adsorption isotherm of each adsorbent were evaluated in 5 concentrations of 250, 500, 750, 1000 and 1250 ppm of contaminants. Final results showed that zeolite 13X compared to other Nano-adsorbents has higher ability to SO2 absorption, and thus the final tests such as temperature and pressure evaluation were performed on the selected sorbent. To further evaluation, the absorbent curves based on two models of BDST (Bed depth service time) and... 

Mobile robots are increasingly being used to perform tasks in unknown environments. The potential of robots to undertake such tasks lies in their ability to intelligently and efficiently locate and interact with objects in their environment. My research focuses on developing algorithms to navigate mobile robots in a partially known environment observed by an overhead camera. The environment consists of stationary and dynamic obstacles and a moving target. The aim of the robot is to select avoidance maneuvers to avoid the dynamic obstacles while approaching the target. The core of the navigation algorithm is based on the velocity obstacle avoidance method and the guidance-based tracking... 

This work uses a hierarchical approach for designing the integrated UWB LNA in MOSFET technology. It first offers a brief treatment of the two important types of noise: the thermal noise of channel and the gate-induced noise, in MOSFET. Then the CS and CS-CG configurations for narrow-band LNAs are considered and the requirements for the wide-band operation in UWB are specified. Noise cancelling technique is also introduced, while five wideband prototype designs, with the noise-cancelling technique used in two designs, are re-examined and tested by simulation. Some proposed methods are then applied to these designs for better performance and obtaining practical insight. The final main... 

With increasing population and lack of habitable spaces, the building heights increased in cities around the world. Placing components of a structure in tandem may cause a permanent failure of the members due to strength reduction. During recent years, this kind of failure occurred in different places of the world, and is called progressive collapse. There are some various samples of the progressive collapse which all are good samples of failures such as building failure in Ronan Point in the UK, Twin Towers or the world trade center in NY, and Pentagon building. According to these issues, different institutions codified guidelines and codes in this field such as Department of Defense as DoD... 

In this research various treatment methods of produce water are discussed and categorized in two groups namely; Basic and advance methods. Four basic treatment methods including; hydro cyclone, flotation, settling and membrane filtration and also four advance treatment methods including; nano filtration, ultra filtration, oxidation and adsorption are considered to compare and to select the most proper ones. To compare the treatment methods a multi criteria decision method namely Analytical Hierarchy Process (AHP) is applied twice to choose the most proper basic and advance treatment methods. The criteria are suggested according to the local conditions of Kharg Island and the similar... 

The present research is aimed at providing solutions for the implementation of the concept of lean production in manufacturing companies. As with increasing production, customer orientation, removal of waste and more arrangements, it can be used in the various equipment manufacturing industries (custom). It can be implemented in accordance with the conditions of each company, in order to help the production sector of the country and in order to develop appropriate strategies to improve performance, especially in the field of production, in line with the principles of pure production. Understanding the principles of pure production helps companies while familiarizing themselves with these... 

In this study, the determination of the distribution and the differences concentration of hydrogen in containment of Bushehr power plant by modeling of containment and Hydrogen removal system of Bushehr power plant during LB-LOCA accident is accomplished. In Bushehr nuclear power plant, which has a unique design, the containment is similar to PWR power plants with a metal sphere, but the installed reactor is a VVER-1000. After a full study on the containment and its systems, the required data for modeling is gathered and afterwards, the engineering handbook is prepared for MELCOR input code and then the modeling and size classification of the containment is done in 4 different ways,... 

During production process in Uranium Conversion Facility (UCF) plant at Isfahan, the liquid waste containing uranium compounds, is directed to evaporation lagoons. Gradually, a considerable amount of precipitation will form at the bottom of these lagoons. Uranium concentration in this precipitation is very high and can range from tens of ppm to the order of a few weight percent. As such, it seems that uranium recovery from the UCF waste liquid is not only economically advantageous, but also effective for protecting the environment.The liquid waste resulting from the uranium extraction process contains a great amount of Fluoride ( ppm or higher) which cannot possibly be thrown away into... 

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... 

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... 

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 ... 

Space debris have increasing importance for space missions. The towing removal scheme is one of the most promising ways for active removal of these debris from LEO orbits. In this approach, an active propelled satellite captures the debris via a space tether and a tethered net which by producing a force opposite to its velocity, it will cause deorbiting and burning the debris in the dense atmosphere. One of the issues with this technique is the danger of tether rupture which for solving that two tethers instead of one can be used. In this research study of active removal of flexible space debris via double tethered towing system has been done. Dynamic modeling has been done with Newton’s and... 

To provide a safe environment for space equipments and infrastructures in addition to managing the role of hazardous objects that are known as space debris, the presented thesis describes a new robust technique to estimate the dynamic states and inertial parameters of Uncooperative Space Objects (USO) with uncertain dynamics in the cluttered orbits. The prescribed method is especially effective to capture stray objects, capture and servicing of the satellites, rendezvous and collision avoidance maneuvers, space explorations as well as Actrive Debris Removal (ADR) missions. Such missions call for high degree of precision and reliable estimation methods. The proposed estimation architecture... 

In this thesis, LMS, NLMS, RLS, ADALINE and ANFIS as five adaptive noise removal methods have been studied with a software application approach. The aim of this study is to obtain the best method to remove noise in terms of signal to noise ratio (SNR) improvement as well as the speed of convergence. In this regard, firstly by applying a frequency sweep input, which is contaminated with white noise, the performance of these algorithms are investigated. Then, an audio signal is utilized as the target input, and the performance of the corresponding algorithms have been analyzed in aspect of filter order and learning coefficient. The results show that by increasing the order of filter and... 

Quality and intelligibility are two aspects of speech that are affected by various factors, such as background noise and echo. The performance of many commercial and military speech-based systems depends on at least one of these aspects of speech. Therefore, this research aims to design an improvement model to remove background noise and reverberation from the speech signal. The model training framework is based on deep learning methods and has a supervised approach in the time domain. The input of this system is the raw waveform of the speech signal mixed with noise and reverberation, and the output is the enhanced waveform of this signal. An architecture is proposed in this thesis based on... 

Clustering is a fundamental problem for data analysis, and it has a lot of variants. In this thesis we focused on the k-center problem, which is one of the most popular and well-studied variants of clustering. In this problem we are given a metric set of points called X, and a parameter k ⩽ |X|. Our goal is to find a set of k centers in X, minimizing the maximum distance of any point of X from its closest center. This thesis has worked on a version of the problem that is harder to solve. we have an extra parameter called z, which represents the maximum number of points that there is no need to be clustered, and we refer to them as outliers. The growth of data that needs to be processed makes... 

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... 

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... 

This study aims to enhance biological nitrogen and phosphorus removal performance by the innovative carbon-based moving carriers (CBMC) and reveals the role of carrier characteristics on the nutrient removal efficiency. In this research, the new carriers with the advantages of both MBBR hybrid system and physicochemical properties of activated carbon were produced based on the recycling of waste materials for the first time via a chemical-thermal process. The analysis revealed that the specific surface area of the new carrier with a rough and highly porous structure was approximately 11.4 times that of the conventional MBBR carrier. This feature plus the other physicochemical properties of...