Studying Instances of Conflict of Interest in Some Job Positions in Iran’s Ministry of Health, Treatment and Medical Education

, M.Sc. Thesis Sharif University of Technology Memari Beyraq, Behzad (Author) ; Talebian, Masoud (Supervisor) ; Fatemi Ardestani, Farshad (Co-Supervisor)

Abstract

This study investigates and enumerates instances of conflict of interests in some job positions in Iran’s Ministry of Health, Treatment and Medical Education. To achieve this goal, we interviewed people involved in the health field and reviewed job descriptions as well. By adopting the prevalent definition of conflict of interests regarding the duties, authorities, and responsibilities, instances of conflict of interests has been relatively identified in each position. The results show that the main reasons (determinants) for cases of conflict of interests can fall into three categories. First, duties of positions are in such a way that being a shareholder, CEO, and member of the board of...

Adaptive Teaching of the Iranian Sign Language Based on Continual Learning Algorithms

, M.Sc. Thesis Sharif University of Technology Memari, Morteza (Author) ; Taheri, Alireza (Supervisor)

Abstract

In addition to being their primary means of communication with the people around them, sign language for deaf children plays a significant role in shaping their intellectual and cognitive development. Research has shown that the use of robots in education has a substantial impact on the learning process of the learner. As the teaching process requires long-term interaction with different users, the use of adaptable techniques enables the creation of a social robot capable of productive interaction with users of varying performance levels. One of the objectives of this research is to use continual learning algorithms to enhance adaptability in the teaching process. Another goal is to design...

Mixed-convection flow of nanofluids and regular fluids in vertical porous media with viscous heating

, Article Industrial and Engineering Chemistry Research ; Volume 50, Issue 15 , 2011 , Pages 9403-9414 ; 08885885 (ISSN) Memari, M ; Golmakani, A ; Dehkordi, A. M ; Sharif University of Technology

2011

Abstract

In this article, the problem of combined forced and natural convection in a vertical porous channel for both regular fluids and nanofluids has been solved by perturbation and numerical methods, taking into account the influences of viscous heating and inertial force. In this regard, various types of viscous dissipation models, including the Darcy model, the power of drag force model, and the clear fluid compatible model, were considered to account for viscous heating. In addition, the mass flux of nanoparticles was also considered in terms of Brownian and thermophoresis mechanisms. The velocity and temperature distributions of both the regular fluid and nanofluid and the Nusselt number...

Liquid-Liquid equilibrium data, density, viscosity, and interfacial tension of ternary system (Toluene-Acetic Acid-Water) at 298.15 K: Experiment and correlation

, Article Journal of Chemical and Engineering Data ; Volume 62, Issue 12 , 2017 , Pages 4133-4143 ; 00219568 (ISSN) Memari, M ; Molaei Dehkordi, A ; Seifkordi, A. A ; Sharif University of Technology

2017

Abstract

Liquid-liquid equilibrium (LLE) data, density, viscosity, and interfacial tension for the ternary system of toluene-acetic acid-water were measured at 298.15 K and 101.7 kPa. The Othmer-Tobias and the Hand correlations were used to check the reliability of the experimental tie-lines. Moreover, the distribution coefficient and the separation factor were explored. It was found from the experimental results that a maximum separation factor value happens at an acetic acid mass fraction of 0.02 in the organic phase. Density, viscosity, and interfacial tension were correlated using the appropriate correlations such that the predicted results have excellent agreement with the experimental data. The...

Sustainable-Resilient Supplier Selection Through Fuzzy Multi-Criteria Decision Making Approaches

, M.Sc. Thesis Sharif University of Technology Varchandi, Sahar (Author) ; Akbari Jokar, Mohammad Resa (Supervisor) ; Memari, Ashkan (Co-Supervisor)

Abstract

Today, with the expansion of business relations at international levels, there are many organizations that operate in global supply chains. Activities at such levels face new types of challenges in various fields of "supply chain management" pillars, of which "supplier selection" is one of them. The possibility of unexpected events, the need to comply with environmental protection laws, as well as the need to take into account social considerations, are among the things that have increased by being in larger supply chains, making it challenging to provide the basic resources needed in such chains and forcing their managers to considering considerations other than what they have always...

An optimization study of a palm oil-based regional bio-energy supply chain under carbon pricing and trading policies

, Article Clean Technologies and Environmental Policy ; Volume 20, Issue 1 , 2018 , Pages 113-125 ; 1618954X (ISSN) Memari, A ; Ahmad, R ; Abdul Rahim, A. R ; Akbari Jokar, M. R ; Sharif University of Technology

Springer Verlag 2018

Abstract

Biomass residues due to their low bulk density typically require frequent transportation from biomass plantations in rural areas to conversion bio-energy power plants. This issue contrasts with environmental protection strategies, especially when power plants are facing different carbon reduction policies that enforce them to emit less than a given specific carbon amount. Although several researchers have investigated bio-energy supply chains concerning environmental policies, the majority of studies have been devoted to strategic decisions over a single planning period. This paper presents a multi-period bio-energy supply chain under carbon pricing (carbon tax) and carbon trading...

Empathizing and systemizing skills influence risky decision making in children

, Article Learning and Individual Differences ; Volume 40 , 2015 , Pages 22-26 ; 10416080 (ISSN) Memari, A. H ; Shayestehfar, M ; Gharibzadeh, S ; Barzegary Banadkooki, E ; Hafizi, S ; Moshayedi, P ; Sharif University of Technology

Elsevier Ltd 2015

Abstract

Tow-mode theories explain that risky behaviors in young individuals may be the result of competition between an affective system (e.g., Empathizing system) and a deliberative system (e.g., Systemizing system). We aimed to investigate a total of 134 children aged 7-12. years old on scores of risky decision making and empathizing and systemizing measures. The primary analysis indicated that systemizers showed higher sensitivity to punishment than those in balanced or empathizer classes (F (2,130) = 14.8, p < 0.001). Furthermore empathizers indicated higher level of risk taking than balanced and empathizer children (F (2,130) = 5.027, p = 0.005). Providing further support for two-mode theories...

Experimental and Numerical Investigation on the Single Drop Liquid-liquid Mass Transfer in the Presence of Magnetic Nano-particles (Ferrofluids) and Magnetic Field

, Ph.D. Dissertation Sharif University of Technology Memari, Mohammad (Author) ; Molaie Dehkordi, Asghar (Supervisor) ; Seif Kordi, Ali Akbar (Co-Supervisor)

Abstract

The main objective of the present work was to improve the turbulence in single drops using ferrofluids (magnetic nanoparticles) in the presence of uniform and oscillating magnetic fields. In this regard, magnetite nanoparticles ($\mathrm{Fe_3O_4}$) were synthesized by co-precipitation method, characterized using DLS, FT-IR, XRD, VSM, and TEM, and their stability was checked by UV-Vis. The obtained results indicate the proper synthesis of nanoparticles with a mean diameter of about 20 nm and by coating their surfaces by silane that were well stabilized in the base fluid. In the numerical section, the governing equations of transport phenomena for a single drop containing magnetic fluids were...

Setar Production Modification With Vibration Analysis

, M.Sc. Thesis Sharif University of Technology Mansour, Hossein (Author) ; Behzad, Mehdi (Supervisor)

Abstract

Setar is a traditional Persian musical instrument. Nowadays, Setar is one of the most common musical instruments in Persian music. A systematic method for Setar production modification has not been introduced yet. This work is the first scientific work about analysis of this instrument. The aim of this study is to undertake early steps for Setar quality improvement. In this thesis, after analysis of the wood using in Setar construction, numerical and experimental methods have been utilized to analyze this instrument. After that, some works has been performed to extract an objective function which can judge about Setar quality. The results show good agreement between experimental and...

Vibration Analysis of Edge Cracked Timoshenko Beam with Continuous Crack Model

, M.Sc. Thesis Sharif University of Technology Heydari, Mahdi (Author) ; Behzad, Mehdi (Supervisor)

Abstract

Structural defects such as cracks may be produced in structures and machineries under fatigue load operating conditions. The presence of crack can lead to catastrophic failures in certain conditions. The occurrence of cracks affects the dynamic and vibration behavior of the structure considerably. These vibrations can be used for identifying the cracks and appropriate actions can be taken to prevent more damage to the system. Therefore, in this thesis vibration analysis of a Timoshenko beam with a vertical and horizontal crack has been considered. A continuous model for vibration analysis of a beam with an open edge crack including the effects of shear deformation and rotary inertia has been...

Fault Detection of Rotary System with Signal Processing and Intelligent Systems

, M.Sc. Thesis Sharif University of Technology Tebyanian, Afshin (Author) ; Behzad, Mehdi (Supervisor)

Abstract

Condition monitoring and fault detection is an important way to provide economy in both time and costs. Many methods are developed for this purpose. Vibration analysis is one of the most important ways in this field. In this thesis, fault detection of mechanical rotary systems with nonlinear and non-stationary nature has been developed by use of empirical mode decomposition (EMD) and Hilbert transform. Firstly the measured signal is transformed into some intrinsic mode functions (IMF’s) by EMD, and then the Hilbert transform is implemented on each IMF. With Hilbert transform, the instantaneous frequency of system and then the mean frequency are obtained. Mean frequency is a key definition...

A Locality Aware P2P Overlay Architecture for Video Streaming

, M.Sc. Thesis Sharif University of Technology Bayat, Navid (Author) ; Akbari, Behzad (Supervisor)

Abstract

Internet video networks have already attracted millions of Internet users, and Internet video is one of the fast growing Internet services. The peer-to-peer (P2P) network is an efficient solution to supporting large scale video streaming on the Internet. P2P networks can deliver live multimedia content to millions of users with low cost at any time, and at anywhere they want. In this thesis, we investigate solutions to enhancing the performance of the unstructured mesh-based. Locality awareness or network proximity is one of the essential characteristics of P2P networks. In live P2P video streaming we face to some challenges like bandwidth heterogeneity of peers, and peer churn. In the P2P...

Analytical and Finite Element Modeling of Rubbing Phenomena in Rotors

, M.Sc. Thesis Sharif University of Technology Alvandi, Mahdi (Author) ; Behzad, Mahdi (Supervisor)

Abstract

Rotor contact with a stationary element of a rotating machine and the subsequent rubbing at the contact area is a serious malfunction that may lead to the machine’s catastrophic failure. In the past decades, many studies have been done on the rubbing phenomena, its different regimes and its various consequences on the machine performance and safety. However, most of them have used a simple model to investigate the rubbing interaction between the rotor and the stator. This simple model consists of the Jeffcott rotor, as a model for the real rotors, and a rigid annular block surrounding the rotor, as a model for the real stators. The objective of this thesis is to build an algorithm to...

Investigation of Magnetodielectric Resonator Antenna Including Gyroteropic Properties of Material

, M.Sc. Thesis Sharif University of Technology Naghdi, Behnam (Author) ; Rejaei, Behzad (Supervisor)

Abstract

So far, investigations have shown that open dielectric resonator antennas (DRAs) offer several advantages at microwave and millimeter wave frequencies. These advantages include small size, large impedance bandwidth, high radiation efficiency, ease of manufacturing and simple feed-coupling mechanisms (such as probe coupling, aperture coupling or proximity coupling to micro-strip lines). Most microwave ferrites have dielectric constants in the desirable range and they can be used in place of dielectric materials. Such ferrite resonator antennas (FRAs) offer a potential advantage in that their permeability tensor can be controlled by applying an external magnetic field. Up to now and by the...

Condition Monitoring and Fault Diagnosis of Rolling Element Bearing in Phase Space

, M.Sc. Thesis Sharif University of Technology Karimi, Majid (Author) ; Behzad, Mehdi (Supervisor)

Abstract

The failure in rolling element bearings as an important part of rotary machine can lead to machine breakdown.Consequently, bearings can reduce reliability of these components and therefore a maintenance strategy is essential to keep reliability in a desired level. The first and primitive strategy is called breakdown or unplanned maintenance. The next is preventive or planned maintenance. In this scheme, maintenance is done after a specified time period irrespective of machine health status. Out of place maintenance is the disadvantage of preventive maintenance. The most effective generation of maintenance strategy is condition based maintenance (CBM) which suggests maintenance decision based...

Vibration Isolation of One Degree of Freedom Systems by Magnetorheological (MR) Damper Under Random Excitation

, M.Sc. Thesis Sharif University of Technology Nakisa, Ali (Author) ; Behzad, Mehdi (Supervisor)

Abstract

The effect of Vibration on the human body is considered as one of the limitations in design and use of HSCs at high speeds. One way to reduce the effect of vibration on the human body is to isolate deck vibrations from the crew by means of seat suspension system. This thesis has studied the effect of using an MR damper on the performance of seat suspension in vibration reduction. In fact, employing MR dampers in seat suspension systems enables us to change their damping. Using an MR damper makes it possible to control seat suspension by semi active control strategies. In this work, a number of proposed mathematical models of an MR damper were studied for numerical analysis and the most...

Analysis of Losses in Articial Dilectric Waveguides at Mm-Wave Frequencies

, M.Sc. Thesis Sharif University of Technology Alizadeh, Arman (Author) ; Rejaei, Behzad (Supervisor)

Abstract

Today as various electronic and telecommunication devices like cell phones and PDAs are being popularized, MMIC technology is gaining a significant importance. One of the priorities of this technology is trying to miniaturize these popular devices. But reducing size of passive microwave components used in these devices requires microwave wavelength to decrease.Components fabricated by conventional deposition techniques aren’t thick enough to reduce the wavelength, so permittivities much higher than those of conventional dielectrics could be a possible solution. Artificial dielectric layers (ADL) can provide such high permittivities.So utilizing these layers can possibly reduce the size of...

Design and Implementation of a Robust Control Method for Rotor Tabilizing in a Three-pole Magnetic Bearing

, M.Sc. Thesis Sharif University of Technology Khansari, Saed (Author) ; Behzad, Mehdi (Supervisor)

Abstract

High speed and high accuracy are two of the major trends for many systems in the 21st century, such as machine tools and semiconductor equipment. For the purpose of high speed, it is well known that active magnetic bearing (AMB) is an inevitable substitute for conventional bearings. The noncontact nature of AMB brings up many advantages over the conventional bearing, including energy efficiency, low wearing, long life span, and absence of lubrication. Hence, AMBs are especially essential for high-speed rotating devices nowadays.
While the 3-pole AMB has been proposed for many years, it received little attention due to the magnetic coupling between poles that makes the 3-pole AMB system...

Theoretical Development of Resonance Acoustic Spectroscopy Technique and Its Applications for Non-destructive Evaluation of Thick-walled Cylindrical Shells

, Ph.D. Dissertation Sharif University of Technology Rajabi, Majid (Author) ; Behzad, Mehdi (Supervisor)

Abstract

Resonance acoustic spectroscopy (RAS) is one of the techniques used for monitoring the production quality and evaluation of mechanical properties of cylindrical components, due to their non-destructivity, high precision and quickness.
In this technique, the resonance effects are caused by the excitation of eigenvibrations of structure by an incident acoustic wave located in far-field. The resonance spectroscopy (isolation and identification of the resonance features) is performed on the far-field scattered pressure field which contains valuable information about the characteristics of the target. Appropriate exploitation of these resonance informations from the theoretical model and...

Finite Element Analysis of Buckling and Snaking Vibration for Drill String in the Horizental Well

, M.Sc. Thesis Sharif University of Technology Ansari, Amir (Author) ; Behzad, Mehdi (Supervisor)

Abstract

Snaking Vibration and buckling of drill string in the horizontal well was investigated in this research. Sinusoidal and helical critical buckling load are obtained for a specific drill string.
Drill string is modeled both analytically and numerically (finite element method). Drill pipes are considered as a clamped-clamped beam with constant cross section and the well is considered as a hollow cylinder. The thickness of cylinder was large enough to model the surrounding soil of the well. Buckling is a complex deformation and is somehow a random phenomenon. In addition, the length and the continuous contact between drill pipes and the well make the finite element model very huge and the...