Sharif Digital Repository

Nowadays providing services beyond the expected performance of users has become the most competition among telecommunication companies. Increase data rate at which a user is able to use a wireless system, you know that most of these companies are competing with each other. However, due to limited power to be sent to a transmitter, the first proposal to increase the data rate of wireless data transmission has a wider bandwidth. This results in increased bandwidth demand and thus sales by the government. During these years, many researchers have tried to increase efficiency in the use of broadband transceiver. These systems due to the wide band signal transmission and high-resolution mass... 

In the first part, a novel electrochemical sensor based on nanocellulose-carbon nanoparticles (NC–CNPs) nanocomposite film modified glassy carbon electrode (GCE) is developed for the analysis of metoclopramide (MCP). The electrochemical behavior of MCP was investigated on the surface of the modified electrode using cyclic voltammetry (CV). Characterization of the surface morphology and properties of NC/CNPs was carried out by scanning electron microscopy (SEM), atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS). Effective experimental variables, such as scan rate, pH of the supporting electrolyte, drop size of the casted modifier suspension and accumulation... 

Miniaturization of electronic devices with portable, flexible and wearable characteristics created a great demand for high-performance microscale energy storage devices with lightweight and flexible properties. Among the energy storage devices, wire-shaped micro-supercapacitors have recently received tremendous attention due to their small size, lightweght, and high flexibility. In the first part, the porous dendritic Ni-Cu film was prepared on Cu wire substrate (CW) for fabrication of high- performance wire-type micro-supercapacitors (micro-SCs). The porous structure with dendritic morphology provides a high surface area, short ion diffusion pathway and low contact resistance between... 

Mode I and II stress intensity factors are derived for an inclined crack breaking the surface of a half-plane which is subjected to an un-symmetrical singular contact loading due to the contact of a tilted wedge with the half-plane. The method used is that of replacing the crack by a continuous distribution of edge dislocations and assume the crack to be traction-free over its entire length. A traction free crack is achieved by cancelling the tractions along the crack site that would be present if the half-plane was un-cracked. The stress distribution for an elastic uncracked half-plane subject to a tilted wedge shaped indenter is derived analytically using the Muskhelishvili’s potential... 

Sharply bent DNA plays an important role in many biological processes such as gene regulation, DNA replication and recombination. DNA cyclization experiments are well suited to study of sharply bent DNA, because they are sensitive to strongly bent conformations. Results of these experiments show that short length DNA molecules are more flexible than predicted by elastic rod model. Therefore, based on these experiments, the elastic rod model is not a suitable model for explaining elastic behavior of DNA at small lengths, although it can explain DNA elasticity at large length scales. Recently, it has been shown that a new model called asymmetric elastic rod model can explain high flexibility... 

Wireless sensor network (WSN) multimedia applications impose new challenges in the design of algorithms and communication protocols for sensor networks. Indeed, wireless multimedia sensor networks (WMSNs) must provide relatively high throughput and low end-to-end delay and jitter while being energy-efficient. In view of these challenges, error control is an important mechanism which enables us to provide robust and high quality multimedia communication in WSNs. In this thesis, we first perform a comprehensive performance evaluation of different error control schemes for multimedia communication over WSNs. The results of our analysis show how wireless channel errors can affect the performance... 

Resin In Pulp(RIP) is One of the most important processes for separation of uranium from ore while concentration of uranium in ore is low , based on adsorption of uranium that exist in the slurry on onion exchanger resins .uranium ore is dissolved in sulfuric acid and slurry that contain uranium is produced,then this slurry enter stirred reactors and adsorption process is performed.RIP are accepted universally and now adays countries such as canada,south africa and australia use this process when concentration of uranium in slurry after leaching process is 100-500 ppm.in iran also this process is performing in ardacan-saghand mine.Kinetic of adsorption process in stirred reactors has been... 

In this thesis, stability and stabilization of fractional-order linear time invariant swarm systems are studied. In recent years it has been proved that the exact model of dynamic agents in most of the swarm systems can be modeled more accurate by fractional order differential equations. Stating the motivation of choosing this subject, the achievements of the thesis can be divided into two general parts: Investigating the stability of fractional-order swarm systems and how to stabilize such systems. After introducing the fractional-order systems and fractional-order model of swarm systems in the introduction part, the literature review is presented in Chapter 2. In Chapter 3 the results... 

Invariant manifolds are important objects in the theory of dynamical systems. The stable manifold theorem is a very important theorem about this concept which proves the existence of stable and unstable manifolds in a wide range of dynamical systems. The importance of invariant manifolds encourages us to view their pictures. It helps us to understand their bahavior. For this purpose, at first we need to approximate the invariant manifold we want to visualize. There are several algorithms designed to approximate invariant manifolds. Those algorithms approximate a set of points on an invariant manifold and then provide an approximation of the manifold by the calculated points. Visualizing an... 

Keratoconus is one of the most common optical (visual, eye) diseases that usually occurs in youth or early third decade of life. In this disease, cornea gets thin and loses it initial shape and becomes conical. Doctors use different methods for its treatment including use of glasses, contact lenses (hard or soft), cornea transplantation and also cross linking of cornea. Each of these methods have their limitations, on the other hand, considering that this disease progresses and intensifies, ophthalmologists use corneal ring implant surgery for the treatment of this disease in its advanced levels. A good ring implant in corneal causes increased strength and also cause corneal to get back to... 

A prismatic high temperature gas-cooled reactor (HTGR), which is a graphite moderated, helium-cooled reactor, is a promising candidate for next generation nuclear power plant in that it enables applications, such as hydrogen production or process heat for petrochemical by supplying heat with core outlet temperatures as high as 1000°C. A Thermal Hydraulic Analysis Code (THAC) for gas-cooled reactors has been developed. THAC implicitly solves heat transfer equation of fuel, graphite block and helium. Three types of fuel pins were considered; solid fuel pin, fuel pins with inside holes and annular fuels with coolant flow from its inside and outside surfaces. THAC predicts axial and radial... 

Nowadays environmental issues are of great importance and one of the most paramount issues is the quality of water, because clean water is vital to our existence. Besides different methods for water purification, water quality testing is a useful and needful tool. Traditional methods for determination of water quality parameters are mainly expensive, time consuming and require highly trained staff. In this study, we have described a centrifugal microfluidic platform (Lab- on – a- CD) for simultaneous determination of different physical and chemical parameters including Nitrite, Free Chlorine and pH. All of the processes from sample injection to detection are integrated on this low-cost and... 

Nowadays, cancer, which has been mentioned as the disease of the century, is the second leading cause of death throughout the world, and its incidence is constantly increasing. Isolation of circulating tumor cells is one of the most critical steps in diagnosing and controlling cancer progression. Due to the rarity of cancer cells compared to other cells in the blood sample, the isolation process requires optimal and high-precision devices. With the advent of inertial microfluidics, the ability to control the particles movement, the processing of blood samples as quickly and accurately as possible, and the viability of cells with a high percentage, introduced microfluidic systems as a... 

In recent years, the user interface of web-based applications has become more and more complicated. Various technologies, architectures, and tools are being used to create a modern user interface. Users interact directly with the user interface, so its functionality has a significant impact on their satisfaction and it is required to design special test suites for the user interface. Furthermore, we need a method to measure the quality and effectiveness of test suites. An effective test suite is a test suite which is able to detect real faults. But this definition is ambiguous, and hence, not practical. A method called Mutation Testing solves this problem and instead of real faults, uses... 

The prediction of deposition efficiency of submicron particles in the pulmonary alveoli has received special attention due to its importance for drug delivery systems, and for assessing air pollutants health risks. In this work, the pulmonary alveoli of a healthy human are idealized by a three dimensional honeycomb like configuration and a fluid-structure interaction analysis is performed to study the normal cyclic breathing hydrodynamics. A viscoelastic model is used for the mechanical behavior of alveolar wall tissue. In contrast to previous works in which the inlet flow rate is predefined, in this model a negative pressure is imposed on the outside surface of the alveolus which causes air... 

An acinus is defined as the complex of airways supplied by one first order respiratory or transitional bronchiole. In this part, the replenishment of oxygen at the alveolar surface occurs by a combination of convective air flow with diffusion of oxygen in the air. So for studying gas exchange in the lung, modeling gas species transport and exchange in an acinus is important. Due to lacking direct measurements of the distribution of oxygen (or carbon dioxide) concentration in the acinus, several mathematical models have been developed and studied by numerical simulations. But in none of them the influence of breathing pattern and the role of blood flow in restricting the gas exchange rate have... 

In this study, an arbitrary Lagrangian-Eulerian (ALE) approach is incorporated with a mixed finite- volume-element (FVE) method to establish a novel moving boundary algorithm to simulate unsteady incompressible flow on non-stationary meshes. The method collects the advantages of both finite-volume and finite-element methods as well as the ALE approach in a unified algorithm capable of solving laminar, transient, and turbulent flows in fluid flow problems with moving boundaries. To enhance the robustness of the extended algorithm, we treat the convection terms at the cell faces using a physical influence upwinding scheme, while the diffusion terms are treated using bilinear finite-element... 

Today, communication sciences are advancing very rapidly; one of these advances is mobile location determination, means finding position of a mobile station. there are some method to location determination; one of these methods is Signal Strength (Power of Arrivals); In this research, Mobile Location Determination using Signal strength measurements in a Location grid will be describe; In this method there is a Mobile Location Server (MLS); In MLS, there re comparable records in database which have been collected from Location grid. When a MS needs to be located, its signaling data (fingerprint) is transmitted to MLS; In MLS, the fingerprints are compared to Data which is store in signature... 

In this thesis, cavitating flow over 2D/3D geometries of cavitators and projectile bodies in stationary and moving conditions are simulated using the "Volume of Fluid" (VOF) technique. The main application of VOF model is for simulating free surface flows. In this work, another capability is added to the VOF algorithm to solve for gas phase and by applying analytical-numerical mass transfer models, cavitation phenomenon is simulated. The developed algorithm precisely simulates the geometrical parameters of supercavities such as dimension and shape in a wide range of cavitation numbers. In addition, the flow parameters of supercavity such as drag coefficient, pressure coefficient inside the... 

Planing crafts in waves are characterized by large and violent vertical motion and acceleration. The hull structure is subjected to high impact loads and the crew experiences high transient vertical acceleration and in most cases the crew needs to lower speed in order to avoid damage to the hull.In recent years, interest on increasingly faster marine vehicles has remarkably grown. Typical planing monohulls are: patrol vessels, pilot boats, rescue vessels, coast guard vessels and small navy vessels. So the behavior of planing monohulls in waves has been a widely researched topic since more and more planing monohulls appeared.The accurate prediction of large amplitude ship motions in severe...