Sharif Digital Repository

A major medical revolution that is helping us overcome some of the worst diseases, including cancer, is angiogenesis, which is based on the processes our bodies use to develop blood vessels. Most human cancers have acquired six essential capabilities: self-sufficiency in growth signals, insensitivity to growth-inhibitory signals, programmed cell death escape, unlimited replication potential, persistent angiogenesis, and tissue invasion that can induce metastasis. In other words, the defense mechanism that prevents any of these acquired capabilities must be neutralized before the cells become malignant and invasive tumors. In fact, tumors in the non-vascular growth stage can only grow up to... 

Recently complex networks, have been widely used as a model to study the behavior of human brain. By affecting different parts the brain, Neuronal disorders change the structure of functional brain networks. Investigating these changes using different graph theory metrics can be a useful methodology for human brain analysis in health and disease. Alzheimer's disease (AD) is a neural disease causing impairment in different brain activities including memory and cognition.The aim of this study is to construct the functional brain network of 17 AD patients and 17 healthy control subjects at resting state condition and analyzing them using the theory of complex networks in order to achieve a... 

The concept of entanglement exists in the common area of the quantum optics and quantum information. Quantum optics is the best tools for investigating of this quantum informational phenomenon experimentally. One of the instruments that let us observes experimentally macroscopy entangeled state is Fabry-Perot Cavity. Striking of photons with the mirror of cavity transfer effective mommentom to it, and oscilating of mirror creates new modes: stocks and anti-stocks modes. Studing quantum state of these modes shows the entangling between photon and phonon (oscilating of mirror) modes. We assume that light beam enters the cavity from a semi-transparent mirror. So cavity is the system with... 

Surface phenomena and dynamic interfacial properties plays a significant role in multiphase gas-liquid & liquid-liquid processes applied in different industrial applications. However, current laboratory equipment and represented methods for dynamic and unsteady state condition caused by motivation of interface of two phases (like rising bubble), in purpose of qualitative investigation of interphase properties are not satisfying enough. Also, common modeling methods are represented with lots of modified assumptions which are not validated properly with experimental results. In current thesis, with development of laboratory tools and applying the “rising bubble method” for investigating the... 

The present study has been performed for better understanding about the dynamic behavior of fluid interfaces in presence of surfactants, nanoparticles and their interactions in gas-liquid dispersion systems. One of the main purposes of this work is to investigate the influence of surface modified nanoparticles on the dynamic behavior of gas-liquid interfaces. For this purpose, the rising bubble experiment was used as one of the most conventional procedures. Local velocities of bubbles rising in nanoparticle solutions were determined experimentally. Influences of silica nanoparticles which were modified via three approaches were investigated in these experiments. Heat treatment was applied to... 

Given the growing advantage of exploiting renewable energy resources over fossil fuels and using distributed generation systems, microgrids seem to be the best solution for reaching the energy-efficient world of the future. Hybrid microgrids are the best options among all other types of microgrids because they make it possible to use AC and DC sources and loads together and at the same time. Since connecting AC and DC sections of a hybrid microgrid leads to the interaction between them, proper control of interlinking converter(s) is crucial for the reliable and stable operation of the entire microgrid. In this study, small signal model of a hybrid AC/DC microgrid consisting of static and... 

Surface phenomena is one of the fundamental branches of science that has many applications in industries related to multiphase processes. One of the most important issues of this knowledge is inter-phase transport phenomena in contacting gas - liquid and liquid – liquid systems. Multiphase systems generally include dispersions such that in many cases are associated with the relative motion between the continuous and dispersed phase. One of the most widely used inter-phase flow systems is dispersion of gas bubbles in the bulk of liquid. The overall efficiency of these systems is often determined by the characteristics of the gas phase. In order to understand the dynamic behavior of such... 

Signal transmission of information on noiseless and lossy channels is an important issue in data transmission. Using the amplifier in the transmission channels is a good solution to help send information on longer channels. In classical communication, information can be coded in the amplitude or phase of the field and an amplifier is responsible for amplifying these parameters. If we consider the conditions ideal and ignore electrical noises, Classical mechanics does not impose any restrictions on the amplification of arbitrary classical signals. Instead, in quantum telecommunications the information encoded on the quadrature of the electromagnetic field are mounted on quantum states, such... 

Interfacial phenomena and properties of interphase surfaces in dynamic mode play an important role in industrial processes that include gas-liquid and liquid-liquid multiphase flows. As well as, interface knowledge leads to better understanding of natural and fundamental phenomena. The present study has been performed for understanding about dynamic behavior of interphase surfaces in the presence of nanoparticles and hexane vapor in gas-liquid dispersion systems. In this research, rising bubble method has been used as one of the most conventional techniques. Accordingly, aqueous solutions of nanosilica were prepared in concentrations of 50, 100, 200, 400 and 1200 ppm as continuous phase... 

Developing a simple, cost effective and accurate detection method for L-lysine (Lys), L-leucine (Leu) and glycine (Gly) as the important analytes in clinical diagnostics, biological processes and food industries is of great interest. Therefore, in the first part of this research, cellulose nanofibrils (CNFs) were coated on a quartz crystal microbalance (QCM) surface by spin coating to achieve a QCM biodetector for Gly. Thus, the two-layer CNFs coating was selected as sensing film and was applied for following experiments. In the next step, the coated QCMs were carefully characterized before and after interaction with Gly using water contact angle (WCA), Fourier transform infrared... 

Developing a simple, cost effective and accurate detection method for L-lysine (Lys), L-leucine (Leu) and glycine (Gly) as the important analytes in clinical diagnostics, biological processes and food industries is of great interest. Therefore, in the first part of this research, cellulose nanofibrils (CNFs) were coated on a quartz crystal microbalance (QCM) surface by spin coating to achieve a QCM biodetector for Gly. Thus, the two-layer CNFs coating was selected as sensing film and was applied for following experiments. In the next step, the coated QCMs were carefully characterized before and after interaction with Gly using water contact angle (WCA), Fourier transform infrared... 

One of the major reasons causing cracks in external surfaces of concrete arch dams are thermal loads. Therofore, in order to avoid instabilities due to function of thermal loads in association with hydrostatic and hydrodynamic pressures, a precise evaluation of temperature distribution through dam body is indispensable. In this study, effects of thermal loads mostly on upstream surface of Karun-3 concrete arch dam in Iran were examined using a 3-D finite element method considering water level fluctuations. Also the influence of operatvie boundry conditions in our problem which are water temperature, air temperature and solar radiation was precisely taken into account. Moreover, nonlinear... 

The classical economic batch quantity (EBQ) model assumes that all produced items have a perfect quality. But in real-life production systems, generation of defective items is inevitable. A portion of these defective items is considered to be scrap , while the other is assumed to be reworkable and reworking them can reduce costs and increase productivity. In this thesis we have studied the economic batch quantity for a single stage production system with rework and scrapping . We want to satisfy the customer demand and minimize total costs of the system like set up costs , production costs , rework costs , holding costs , shortage costs and scrapping costs . In the first chapter of this... 

The behavior of pile foundations under earthquake loading is an important issue that affects the performance of structures. Design procedures have been developed for evaluating pile behavior under earthquake loading; however, the application of these procedures to cases involving liquefiable ground is uncertain. The performance of piles in liquefied soil layers is much more complex than that of non-liquefying soil layers because not only the superstructure and the surrounding soil exert different dynamic loads on pile, but also the stiffness and shear strength of surrounding soil diminishes over time due to both non-linear behavior of soil and pore water pressure generation. In this... 

In this thesis, based on the taking-off and landing of aircraft with GE 21-J85 turbine, the low cycle fatigue (LCF) test for superalloy used in first stage blades is considered. The LCF tests were performed on both coated and uncoated Rene 80 which are used in GE 21-J85 turbine at R = (min/max) = 0, strain rate of 2 10-3 s-1 and 760oC, 871oC and 982oC. To produce specimens, an investment casting method was used so that adequate amount of polycrystalline round bars could be obtained. The specimens were all homogenized and solution treated. After the inspection, some specimens were coated with pack cementation method in CODEP-B powder in H2 atmosphere. The coated and uncoated specimens all... 

In this thesis, two-level optimal control of uncertain and non-uncertain large-scale systems is presented. In the proposed two-level approach, using a decomposition/coordination framework, the large-scale system is first decomposed into several interactive subsystems, at the first-level, where a smaller optimization problem is solved at each subsystem. At the second-level, a substitution type prediction method, as a coordination strategy, is used to predict the interaction between subsystems. The coordinator mainly evaluates the next update for the coordination parameters and continues to exchange information with the first-level, so that the overall optimum solution is obtained. It is shown... 

In this study a layer with compressive residual stress was created by severe shot peening and hence surface grains was changed to nanostructure. Fatigue life will be increased as a result of compressive residual stress. Surface roughness increase, is one of the disadvantages of severe shot-peening process. Re-shot-peening with the smaller shots and lower intensity is proposed for reducing surface roughness. Numerical simulation as a powerful method, used to investigate the effects of shot-peening parameters on the residual stress distribution, surface roughness and grain size. Obtained results indicate that more energy in process can improve residual stress distribution and grain size unlike... 

A special steel beam-to-column connection, named Khor-jini, is commonly used for steel framing system in Iran. In this system, two continuous beams are passed next to the columns and are connected to the column side using seated brackets.This type of connection has been common in Iran from the late past. Unfortunately, the seismic behavior of Khorjini frames had not been sufficiently studied prior to Manjil Earthquake of 1990. Due to very large damages which occurred in steel structures especially in connections during the said earthquake, the seismic behavior of this type of connection was studied and some of its weak points were recognized.In this study non-linear...