Sharif Digital Repository

Polyampholyte hydrogels are hydrophilic networks that contain both positively- and negatively-charged functional groups on their structure. Polysulfobetaines are the most important type of polyampholytes, which have been extensively studied. However, these hydrogels exhibited poor gel strength causing limitation of their applications. Consequently, much attention has been focused on the preparation of nanocomposite hydrogels with high gel strength and lower cost using organomodified clays. In this project, Novel polyampholytic superabsorbing nanocomposites based on the zwitterionic sulfobetaine monomer [3-(methacrylamido)propyl)]dimethyl(3-sulfopropyl) ammonium hydroxide (MPDSAH) were... 

We consider a special class of Congestion Games enhanced with a notion of time.Network Routing problems, such as road traffic networks, computer neworks, and evacuation problems are some applications of this class of games. Two subclasses of these games, namely atomic and non-atomic is considered in this article, both of them introduced in 2009. Some of the existing results are Nash equilibria existence proof for “single-source single-sink” case, and a mechanism for improving price of anarchy in the non-atomic subclass. There are also some results in the atomic subclass of this game.We extend both models of atomic and non-atomic subclasses to “multi-source,multi-sink” configurations. We call... 

Acidizing is one of the widely used practices of formation damage remediation. The success of this rather expensive job depends on the precise design and operation. Though, improper execution of an acid job, not only does not improve the formation damage but also can contribute to even more damage itself. For this purpose, it is critically important to thoroughly design an acidizing job conducting extensive lab experiments and utilizing numerical tools before operation in order for a successful acidizing. Unlike, carbonate acidizing, the chemistry of sandstone acidizing is very complex and challenging because of the wide variety of minerals and aqueous species present in the system. Hence, a... 

In the framework of the Standard Model of Particle Physics, Quantum Chromodynamics (QCD) is known to be the only theory which describes the strong nuclear force. Because of the property of asymptotic freedom, perturbative methods fail to describe QCD at low energies. Here, mesons and baryons build the main degrees of freedom of QCD. To describe the dynamics of mesons at low energies, nonperturbative methods are used. The Nambu–Jona-Lasinio (NJL) model is one of the most important effective models, which is used to study the nonperturbative phenomena of QCD at low energies. The Lagrangian density of this model includes a local four-fermion term,which descibes the interaction between the... 

Quantum Chromodynamics (QCD) is the theory of strong interaction. Two main properties of QCD in low energies are chiral symmetry breaking and confinement. At finite temperature, QCD exhibits a certain transition from a chirally broken phase to a chirally restored phase and liberation of color charge. Lattice QCD at finite temperature shows a crossover transition at vanishing or small chemical potential while the model-dependent studies, e.g. the Nambu-Jona--Lasinio model predicts a first-order phase transition at large chemical potentials. The first order and crossover transition lead to the existence of a critical point in the phase diagram of QCD. Determining the nature of the phase... 

This work presents the methodology to investigate Optimum Camera Installation Angle (OCIA)while employing the so called?Vision Based Navigation (VBN)? in urban areas.The approach is suitable for future general aviation aircraft as envisioned in Small Air Transportation System (SATS) as well as Unmanned Aerial Vehicles (UAV).Due to practical constraints, the work is limited to the maneuvers in the vertical plane while conducting Simultaneous Localization and Mapping (SLAM) technique.This technique was originated in robotics and is commonly used to guide both ground based and low speed aerial robots in unknown environments involving different types of obstacles. A variety of camera... 

Hand in hand with the flourish of the biodiesel industries, glycerol has turned into an abundant waste chemical posing obstacles to their large-scale implementation. Devising measures for efficient transformation of glycerol into value added products is a promising alternative to its large-scale disposal into the nature that would also increase the competitiveness of biodiesel fuels. In this study, production of lactic acid (LA) as a valuable chemical with wide applicability is studied in a continuous process with glycerol as a cheap and convenient feedstock. In this regard, the state-of-the-art approaches in catalytic conversion of glycerol to LA are reviewed. A catalytic method using... 

Purpose of ongoing thesis is providing a tool for suitable modeling, increase efficiency and decrease construction cost of solar absorption heat pump. At first, the solar absorption heat pump is modeled by the thermodynamic laws. Then, this model is converted to the new standard mathematical programming model using exergy and thermodynamic Analysis with considering all technical and economic constrains. This mathematical model is optimized by Genetic algorithm (GA). Because of the nonlinear objective function and the constraint, GA is used as optimization algorithm. After applying GA, optimized parameters of cycle heat exchanger designing and its electricity consumption are calculated.... 

The cosmic ray astronomy was born in 1937 when Victor Hess flied with his balloon to the height of 17,500 feet. He found that the cosmic rays come from out of atmosphere. There are three fundamental questions from that time. The goal of all cosmic ray's experimental activities and related theories is finding out the answer of these questions. The first question is about the energy and composition spectrum of cosmic rays. The second one is finding the sources which can product the very high energy particles such as the protons with the energy of 1021eV found in some observatory such as AGASA and Haverah Park. The last question is the process of diffusion of cosmic rays in the galaxy. One of... 

Automation of the software development process is the software engineers' final goal, but with the current facilities and knowledge in software engineering, it is not possible to automatically generate the whole software. Usually all the software in a specific domain contain common behaviors, which by careful exploration of these common behaviors and automation of code generation in these sections, the cost and time of projects' execution can be reduced. According to Model Driven Development (MDD), the first step in software development is creating appropriate models. For creating models, metamodel is required; therefore, we need to create a specific motamodel for the chosen domain or use... 

With the growth of the urban population and the increase in private car ownership, negative implications of transportation, such as traffic congestion and environmental pollution has increased. A good solution to this problem is development of traffic infrastructures. However, it is not sufficient by itself and better management strategies for solving these problems are needed. One of the related approaches, is high occupancy toll lane. The main purpose of this study is modeling user’s mode choice behavior in the presence of high occupancy toll lane and pricing some highway lanes in Tehran. Another important purpose of this study is to find affective factors that have an influence on users... 

Underground water is one of major resources of drinking water in Iran and thus, its quality (in terms of absence of pollutants) is a matter of great importance. The main goal of this research was to investigate the pollution concentration in underground water and soil in two regions: Dasht-e-naz in Sari and the fields near Sarkhoun gas refinery. The second goal was to determine the source and measure the distribution of the pollutants (in case of presence) and determine potential risks caused by them. The first step was to perform experimental tests in the two regions. In Sari's Dasht-e-naz region, a number of wells were chosen for sampling according to the direction of underground water...