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radaei--payam
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Modeling and optimization of gelatin-chitosan micro-carriers preparation for soft tissue engineering: using response surface methodology
, Article Materials Science and Engineering C ; Volume 75 , 2017 , Pages 545-553 ; 09284931 (ISSN) ; Mashayekhan, S ; Vakilian, S ; Sharif University of Technology
2017
Abstract
Electrospray ionization is a wide spread technique for producing polymeric microcarriers (MCs) by applying electrostatic force and ionic cross-linker, simultaneously. In this study, fabrication process of gelatin-chitosan MCs and its optimization using the Response Surface Methodology (RSM) is reported. Gelatin/chitosan (G/C) blend ratio, applied voltage and feeding flow rate, their individual and interaction effects on the diameter and mechanical strength of the MCs were investigated. The obtained models for diameter and mechanical strength of MCs have a quadratic relationship with G/C blend ratio, applied voltage and feeding flow rate. Using the desirability curve, optimized G/C blend...
Design and Fabrication of Hydrogel Microcarrier for Tissue Engineering
, M.Sc. Thesis Sharif University of Technology ; Mashayekhan, Shohre (Supervisor) ; Yaghmaei, Soheila (Supervisor)
Abstract
Microcarriers (MCs) are an attractive technology with various applications in tissue engineering. In this study, chitosan/gelatin MCs were fabricated with blends of different ratio of chitosan/gelatin, by using a setup containing high voltage electrostatic field and syringe pump. Optimization of blend ratio, voltage and syringe pump flow carried out by the “Design expert” software leads to fabrication of MCs with constant diameter while having various elasticity. Mechanical strength and elasticity of MCs were determined. Human umbilical cord mesenchymal stem cells (hUCMSCs) were cultured on MCs dynamically by using mini-rocher in an incubator. Cells adhesion on MCs were successfully shown by...
Analysis and Study the Effect of Knowledge Management Implementation on Productivity Case Study: Tehran Regional Electric Company
, M.Sc. Thesis Sharif University of Technology ; Mostafavi, Mostafa (Supervisor)
Abstract
The successful development and implementation of a knowledge management system requires principles and instructions compatible with the organization. In the absence of essential and domestic components of a given organization, the process of knowledge management implementation will fail to be successfully completed. There are now various models for the implementation of knowledge management; however, these models only recommend general strategic guidelines, hardly offering any specific strategic plans as to how organizations can successfully and effectively implement knowledge management. Since the promotion of productivity is the ultimate goal of knowledge management, the present research...
Coordinated Scheduling of Power and Natural Gas Systems Considering Demand Uncertainty
, M.Sc. Thesis Sharif University of Technology ; Rafiee, Majid (Supervisor)
Abstract
The everyday increasing electricity consumption of household and industrial sectors across the world, and also the limited generation capacity and fuel supplies has led electricity companies, whether in private or government sectors, to focus deliberately on power generation planning, its costs, risks and constraints Because of many reasons including high efficiency, low cost of capital investment, expeditious permitting, and operation flexibility of gas-fired generating units, electricity companies prefer them to old ones like coal-fired or oil-fired generating units. Thus natural gas has gained a significant share in the portfolio of electricity generation fuel resources, and it is...
Robust DTC control of doubly-Fed induction machines based on input-output feedback linearization using recurrent neural networks
, Article Journal of Power Electronics ; Volume 11, Issue 5 , 2011 , Pages 719-725 ; 15982092 (ISSN) ; Hashemnia, M. N ; Faiz, J ; Sharif University of Technology
2011
Abstract
This paper describes a novel Direct Torque Control (DTC) method for adjustable speed Doubly-Fed Induction Machine (DFIM) drives which is supplied by a two-level Space Vector Modulation (SVM) voltage source inverter (DTC-SVM) in the rotor circuit. The inverter reference voltage vector is obtained by using input-output feedback linearization control and a DFIM model in the stator a-b axes reference frame with stator currents and rotor fluxes as state variables. Moreover, to make this nonlinear controller stable and robust to most varying electrical parameter uncertainties, a two layer recurrent Artificial Neural Network (ANN) is used to estimate a certain function which shows the machine...
Alginate/PVP/Pomegranate Seed Hydrogels as Bio-sorbents of Water Pollutants
, M.Sc. Thesis Sharif University of Technology ; Frounchi, Masoud (Supervisor) ; Mollaabasi, Payam (Co-Supervisor)
Abstract
In the past decades, hydrogels have been used as an adsorbent with high potential to remove pollutants in water. Hydrogels are three-dimensional polymer networks that have the ability to absorb and store water and water-soluble compounds due to the presence of hydrophilic functional groups in their structure. Different particles with unique characteristics can be used to increase the efficiency of hydrogel absorption. Based on the type of pollutant, hydrogels are divided into three different forms, including particles, films and nanocomposites. In this research, the absorption effect of metal cations as well as the absorption kinetics of polyvinyl pyrrolidine-based hydrogels, sodium...
The Effect of Olive Leaf Green Inhibitor on the Corrosion Resistance of Steel Reinforcement in Geopolymer Concrete Pore Solution
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor) ; Hosseini, Payam (Co-Supervisor)
Abstract
In this research project, the aim was to investigate the potential of olive leaf extract as an eco-friendly inhibitor for enhancing the corrosion resistance of reinforcing steel in simulated geopolymer concrete pore solution (GCP) containing chloride ions. The inhibitory effects of olive leaf extract were evaluated using various electrochemical techniques as well as scanning electron microscopy. The main phenolic compounds present in olive leaf extract were identified using high performance liquid chromatography (HPLC). Moreover, the elements and chemical bonds present in the surface passive film of the steel bar immersed in the olive leaf inhibiting system were characterized using...
Iran’s oil development scenarios by 2025 [electronic resource]
, Article Energy Policy ; Volume 56, May 2013, Pages 612-622 ; Sharif University of TechnologyDynamic Simulation and Control of Reactive Systems Involving Metabolic Pathways
, M.Sc. Thesis Sharif University of Technology ; Bozorgmehry Bozarjomehry, Ramin (Supervisor) ; Setoodeh, Payam (Co-Supervisor)
Abstract
In this project, modeling, simulation, and control of the Saccharomyces Cerevisiae were studied. In the first section, simulation and control of a structural model of saccharomyces Cerevisiae were performed. Fuzzy Logic Controller (FLC) as a model-independent controller and Global Linearization Controller (GLC) as a model-based controller were designed. Additionally, two types of Kalman filters were designed to predict all states of the structural model: 1-Extended Kalman Filter (EKF), 2- Unscented Kalman Filter (UKF). As a concise explanation, the control action of the GLC is a function of all states of the model, and since that measuring all metabolites is not practical, the EKF and UKF...