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farokhi--mehdi
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Synthesis and Characterization of a Novel Hydrogel Wound Dressing based on Silk Fibroin and Zinc Oxide Nanoparticles
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor) ; Shokrgozar, Mohammad Ali (Supervisor) ; Farokhi, Mehdi (Co-Supervisor)
Abstract
Recently, some wound dressings have been designed that are expected to enhance the wound healing process and prevent blood bleeding and infection. Polymeric dressings have attracted attention due to their biocompatibility, biodegradability, lack of toxicity, and non-allergenic nature. There is widespread interest in using silk fibroin (SF) for this purpose because of its unique properties. Given these points, we have designed an injectable antioxidant hydrogel wound dressing based on SF and Polydopamine(PDA) modified ZnO nanoparticles. First, ZnO nanoparticles were doped with Cu and then modified with PDA (ZnCuO@PDA). XRD, FTIR, SEM, and TEM characterizations were carried out to confirm the...
Finding the Hamiltonian Cycle Corresponding to the Boundary of a Pseudo-Triangle in its Visibility Graph
, M.Sc. Thesis Sharif University of Technology ; Zarei, Alireza (Supervisor)
Abstract
The visibility graph of a simple polygon represents visibility relations between its vertices. Since each vertex in a polygon is visible from the two vertices adjacent to it on the boundary of the polygon, this boundary is analogous to a Hamiltonian cycle in the visibility graph of the polygon. Therefore, visibility graphs are Hamiltonian. Finding this Hamiltonian cycle can be of great help when solving visibility graph recognition problems, in which one should decide whether a given graph is a visibility graph of a simple polygon; and reconstruction problems, which include constructing the polygon corresponding to a given visibility graph. These problems have been solved for the special...
Analysis of Bruno Latour’s Metaphysics and Realism
, M.Sc. Thesis Sharif University of Technology ; Taghavi, Mostafa (Supervisor)
Abstract
Bruno Latour is one of the well-known contemporary philosophers in the field of science and technology studies. He is specially famouse for his work in laboratory studies and also for rejecting the dualities of modernity. By rejecting subject/object division, Latour opens new perpectives in Ontology. Ontology is one of the most important contributions of Latour to philosophy. He is also one of the primary developers of actor-network theory.In this research, I elaborate on ontological ideas of Latour. First, I will clarify his position in regard to modernity and show how he withdraws from dualities of modernity. Then I will explain his ontological pluralism. Based on this approach, I will...
Re-Creation of Lost Gas Layer on Superhydrophobic Surfaces with Micro/Nanostructures
, M.Sc. Thesis Sharif University of Technology ; Mosavi, Ali (Supervisor)
Abstract
Due to their unique characteristics, such as drag reduction, anti-fouling, and enhancing condensation, hydrophobic and superhydrophobic surfaces have attracted a lot of attention in the past decades. Since approximately 4% of the fossil fuel usage and 14-19% of the air pollution (including greenhouse gases, sulfur, and so forth) are attributed to naval activities, and the dominant form of drag on vessels is friction, drag reduction will not only reduce the cost and usage of fossil fuels, but it will also have numerous environmental benefits
In vitro biocompatibility evaluations of hyperbranched polyglycerol hybrid nanostructure as a candidate for nanomedicine applications
, Article Journal of Materials Science: Materials in Medicine ; Vol. 25, issue. 2 , 2014 , pp. 499-506 ; ISSN: 09574530 ; Shokrgozar, M. A ; Vossoughi, M ; Farokhi, M ; Sharif University of Technology
2014
Abstract
In the present study, a detailed biocompatibility testing of a novel class of hybrid nanostructure based on hyperbranched polyglycerol and β-cyclodextrin is conducted. This highly water soluble nanostructure with size of less than 10 nm, polydispersity of less than 1.3, chemical tenability and highly branched architecture with the control over branching structure could be potentially used as a carrier in drug delivery systems. To this end, extensive studies in vitro and in vivo conditions have to be demonstrated. The in vitro studies include in vitro cytotoxicity tests; MTT and Neutral Red assay as an indicator of mitochondrial and lysosomal function, and blood biocompatibility tests such as...
Design and Fabrication of Inductive High Temperature Superconducting Fault Current Limiter
,
Ph.D. Dissertation
Sharif University of Technology
;
Vakilian, Mehdi
(Supervisor)
;
Fardmanesh, Mehdi
(Supervisor)
Abstract
The continuous rise in electricity demand and the ever growing power generation in different power networks over the world have caused the short circuit level in the power systems to exceed the operational rating of the installed power devices (including cables, circuit breakers and buses). Replacing these devices with new higher rating devices is an expensive solution. From this point of view, utilizing fault current limiters is an economical solution. Superconducting fault current limiters form an efficient category of current limiters. This type is expected to be studied and used widely in future due to their advantages. In this thesis, the first chapter reviews the superconductivity...
Sustainable release of vancomycin from silk fibroin nanoparticles for treating severe bone infection in rat tibia osteomyelitis model
, Article ACS Applied Materials and Interfaces ; Volume 9, Issue 6 , 2017 , Pages 5128-5138 ; 19448244 (ISSN) ; Mottaghitalab, F ; Eslami, M ; Gholami, M ; Kundu, S. C ; Kaplan, D. L ; Farokhi, M ; Sharif University of Technology
American Chemical Society
2017
Abstract
The successful treatment of bone infections is a major challenge in the field of orthopedics. There are some common methods for treating bone infections, including systemic antibiotic administration, local nondegradable drug vehicles, and surgical debridement, and each of these approaches has advantages and disadvantages. In the present study, the antibiotic vancomycin (VANCO) was loaded in silk fibroin nanoparticles (SFNPs) and the complexes were then entrapped in silk scaffolds to form sustained drug delivery systems. The release kinetics of VANCO from SFNPs alone and when the SFNPs were entrapped in silk scaffolds were assessed at two different pH values, 4.5 and 7.4, that affected the...
Enhancement of THz Radiation from Josephson Junctions in Superconductors Using Electromagnetic Resonators
,
M.Sc. Thesis
Sharif University of Technology
;
Ahmadi Boroujeni, Mehdi
(Supervisor)
;
Fardmanesh, Mehdi
(Supervisor)
Abstract
Terahertz waves which includes frequencies between 100 GHz to 10 THz of electromagnetic spectrum have found many applications in science, medical treatments and industry. One of the recent methods to produce these waves is using nonlinear properties of superconductors based on Josephson junctions which inherently appear in some superconductors called BSCCO. Stack of intrinsic junctions of these superconducting materials can radiate terahertz waves by only applying a DC voltage across them. This Thesis investigates some of these structures based on Josephson junctions to produce coherent radiation of terahertz waves. For the optimization of the radiation power, this study also investigates...
On the Spectrum of Modified Theories of Gravity
, M.Sc. Thesis Sharif University of Technology ; Golshani, Mehdi (Supervisor) ; Sheikh Jabbari, Mohammad Mehdi (Supervisor)
Abstract
There are different approaches in modifications of General Relativity as the theory of gravity. The modified theories of gravity are important cases in this context, which mostly start by modifying the Einstein-Hilbert action, while keeping the general covariance. Within the modified theories of gravity, we consider two cases. The first is the f(R) theories of gravity, and the second is curvature squared theories of gravity with an action like S = ∫d4x pg( 116GR + (R)2 + R2 +(R)2). Curvature squared theories of gravity have interesting feautures, most important of which is renormalizability, in contrast with General Relativity. But this advantage, as noted by K.S. Stelle in 1977 comes at...
On Thermodynamics and Phase Space of Near Horizon Extremal Geometries
, Ph.D. Dissertation Sharif University of Technology ; Sheikh-Jabbari, Mohammad Mehdi (Supervisor) ; Golshani, Mehdi (Co-Advisor)
Abstract
Near Horizon Extremal Geometries (NHEG), are geometries which may appear in the near horizon region of the extremal black holes. These geometries have SL(2;R)U(1)n isometry, and constitute a family of solutions to the theory under consideration. In the first part of this report,their thermodynamic properties are reviewed, and their three universal laws are derived. In addition, at the end of the first part, the role of these laws in black hole thermodynamics is presented. In the second part of this thesis, we review building their classical phase space in the Einstein-Hilbert theory. The elements in the NHEG phase space manifold are built by appropriately chosen coordinate transformations of...
Optimal Multicriteria Design of HTS Transformer and Construction of a Laboratory Scale Sample
, Ph.D. Dissertation Sharif University of Technology ; Vakilian, Mehdi (Supervisor) ; Fardmanesh, Mehdi (Co-Supervisor) ; Hekmati, Arsalan (Co-Supervisor)
Abstract
Employing high-temperature superconducting (HTS) tapes, instead of copper or aluminum wires for winding in a superconducting transformer, results in a series of significant advantages; such as: smaller volume, lighter weight, higher efficieny, greatly extended overload capability, better voltage regulation, lower life cycle cost, fault current limiting capability, lower environmental pollution and lower risk potential against fire hazards.In this thesis, optimal design of flux diverter using genetic algorithm for axial short circuit force reduction in HTS transformers has been performed. Then, multilayered flux diverters have been proposed for reduction of weight and losses. The impact of...
Critique and Survey of Various Formulation of Multiverse Theory
, Ph.D. Dissertation Sharif University of Technology ; Golshani, Mehdi (Supervisor) ; Sheikh Jabbari, Mohammad Mehdi (Supervisor)
Abstract
Multiverse scenario has been recently addressed by physicists and they have found it useful in many areas of physics. In this dissertation, I have treated some issues about multiverse such as the kinds of multiverses, the arguments for or against multiverse, areas in which multiverse is introduced, etc. This dissertation has six chapters and an appendix. In the chapter one, some classifications of multiverse is introduced, and also some definitions of the concept of a world is presented. Then, my classification and definition of a multiverse and a world is introduced. In the chapter two, the concept of possible worlds in philosophy and its relationship with multiverse hypothesis is examined....
Monitoring of Valve Leakage in Internal Combustion Engine Using Acoustic Emission Method
, Ph.D. Dissertation Sharif University of Technology ; Behzad, Mehdi (Supervisor) ; Mehdigholi, Hamid (Supervisor) ; Ahmadi, Mohammad Mehdi (Co-Advisor)
Abstract
Valve leak detection is very important due to bad direct effects on parts life and engine power. Acoustic emission (AE) has a good known ability on leak detection between fault detection methods. The aim of this thesis is presenting the ability of AE method for valve leak detection in internal combustion engines. The research method in a general framework based on the idea that firstly some evaluations were done in static tests for leakage due to three faults including clearance, quasi-crack and notch. Then, the evaluations were continued with dynamic analysis of rotational speeds and different loads on the engine. Finally, the neural network approach was used to automatically detect all...
A Multi-Objective Robust Optimization Model for Logistics Planning in the Earthquake Response Phase [electronic resource]
, Article Transportation Research Part E: Logistics and Transportation Review, Elsevier ; Volume 49, Issue 1, January 2013, , Pages 217–249 ; Eshghi, Kourosh ; Dullaert, Wout ; Sharif University of Technology
Abstract
Usually, resources are short in supply when earthquakes occur. In such emergency situations, disaster relief organizations must use these scarce resources efficiently to achieve the best possible emergency relief. This paper therefore proposes a multi-objective, multi-mode, multi-commodity, and multi-period stochastic model to manage the logistics of both commodities and injured people in the earthquake response. Also, a robust approach is developed and used to make sure that the distribution plan performs well under the various situations that can follow an earthquake. Afterwards, it proposes a solution methodology according to hierarchical objective functions and uses it to illustrate the...
Distributed Generation Planning in Deregulated Electric Industry Using Multi-objective Optimization
, M.Sc. Thesis Sharif University of Technology ; Ehsan, Mehdi (Supervisor)Modeling of HV Substation Automation Systems and Evaluating of Operation Failure
, M.Sc. Thesis Sharif University of Technology ; Vakilian, Mehdi (Supervisor)
Abstract
In two past decades, a revolution has occurred by emerging of substation automation system in field of substation control and protection system. The traditional control system has changed to the modern automation systems which are based on computer networks. The development of this project become possible by having experience in and being familiar with automation systems, studying equipment specifications, tasks, and criteria and analyzing operation of various systems. The main target of this thesis is evaluating the automation system precisely and exhaustively and developing a model based on mathematical relations. This model is founded based on the application and analysis of the networks....
Relative Merits of the Two Famous Formulations of Bohmian Mechanics
, Ph.D. Dissertation Sharif University of Technology ; Golshani, Mehdi (Supervisor)
Abstract
The goal of this thesis is to evaluate the strengths and weaknesses of the two existing formulations of Bohmian mechanics. The first one was proposed by Bohm, and emphasizes on the dynamics being second-order, and in which, the key tool for explaining the quantum phenomena is a non-classical potential, called "the quantum potential". In this approach, the postulates of de Broglie's "pilot-wave" theory, which now is known as Bohmian mechanics, are non-fundamental and are special to the atomic level. The possibility is proposed that these postulates become subjected to some modifications at the nuclear or lower levels, but no particular way for performing such modifications is suggested. The...
Evaluation of Electromagnetic Forces on three-phase Core-Type Power Transformer Windings during Inrush Current by FEM
, M.Sc. Thesis Sharif University of Technology ; Vakilian, Mehdi (Supervisor)
Abstract
Inrush Current is a form of over-current that occurs during energization of a transformer. For power transformers, the magnitude of the first peak of inrush current is initially several times the rated load current but slowly decreases until it finally reaches the normal exciting current value. This process typically takes several minutes. Time-variant axial and radial electromagnetic forces under inrush current and short-circuit current are calculated (by finite element method; FEM), and compared. An analytic method is presented for computation of inrush current in transformer. The simulation results obtained by this proposed method are compared with the measured values. A compact...
Ground Water Denitrification by Packed Bed Bioreactor With KMT Packing
, M.Sc. Thesis Sharif University of Technology ; Borghei, Mehdi (Supervisor)
Abstract
In this study biological denitrification method by moving bed biofilm reactor is investigated. The main advantage of MBBR reactor is due to their capacity for high removal rates and low operational problems such as clogging. Two MBBRs in series with 3 liter volume each, were designed in experimental set up and used in this research. Nitrification reactor worked under aerobic conditions and denitrification reactor operated under anaerobic conditions. Methanol was used as carbon source in the reactors throughout the study. Fifty percent of each reactor volume was occupied with KMT1 packing. To finding the optimum nitrate loading rate, the concentration of ammonium and nitrate were changed from...