Sharif Digital Repository / Sharif University of Technology / Search result

Numerical Investigation of Nano-Particles Dispersion and Deposition in Crossing of Elliptical Obstacles Networkusing Lattice Boltzmann Method

, M.Sc. Thesis Sharif University of Technology Piri, Salman (Author) ; Moosavi, Ali (Supervisor)

Abstract

Investigation of transport and deposition of aerosol particles has been of interest to researchers in many branches of science. Various numerical and experimental methods has been utilized in particulate fluid flows studies. In recent relevant researches lattice Boltzmann method has been widely used and is reported to be a robust and efficient method. In present study, numerical investigation of dispersion and deposition of aerosol particles is studies in the channel, containing elliptical obstacles geometry using Lattice Boltzmann Method. Fluid flow simulations are performed using LBM while for the study of particle transport and deposition, tracking and the motion equations of them,...

Design and Implementation of 6-18 GHz Driver Amplifier

, M.Sc. Thesis Sharif University of Technology Piri, Milad (Author) ; Medi, Ali (Supervisor)

Abstract

Nowadays, application of microwave integrated circuits in commerce and humanitarian military measures plays an important role. When integrated microwave circuits emerged, the dream of producing high quality and low cost amplifiers and mass productionhas been fulfilled. Power amplifiers which are the last block in a communication systemare one of the most important circuits in this field.
Since driver amplifiers are interstage between high and low power sections of a system, should have good specificationsfor both small and large signal analysis. Thus, designing such a circuit can be very challenging. In order to get the desired bandwidth, high-order filters are used as interstage...

Studying the Role of Distraction of Men and Women in Accidents Using Structural Equation Modeling

, M.Sc. Thesis Sharif University of Technology Piri, Mehran (Author) ; Kermanshah, Mohammad (Supervisor)

Abstract

Crash severity is among the fundamental safety indicators in transportation. In recent years, distracted driving has been one of the biggest concerns in road crashes. Many scholars have evaluated the effects of distraction in crash severities and injuries. This study uses the latest general estimates system (GES) crash dataset, which is a subset of the US National Automotive Sampling System (NASS) and the structural equation model (SEM) approach to explore the relationships between distraction factors and crash severity in male and female drivers. Using SEM for modeling about 22 thousand observations offers the opportunity to simultaneously examine complex relationships between variables by...

Integrated Dynamic Pricing and Ordering in a Supply Chain With Demand Learning

, M.Sc. Thesis Sharif University of Technology Piri, Saeed (Author) ; Modarres Yazdi, Mohammad (Supervisor)

Abstract

In this study, four pricing models in a supply chain are developed. The first model includes a retailer. The second model also includes a retailer. However in this model we apply the learning technique to update the stochastic demand. In the third model, we consider a supply chain consisting of a retailer and a manufacturer. Finally, in the fourth model we consider a supply chain consisting of a retailer and a manufacturer and like the second model; we apply the learning technique to update the stochastic demand. In all models we assume that a single product is sold in a monopoly market. In this study we seek to simultaneously determine decisions about production, pricing and ordering to...

Novel Approach Towards Mechanical and Thermal Resistant Capillary Microextraction by Sol-Gel Technique in On-Line Combination with High Performance Liquid Chromatography

, Ph.D. Dissertation Sharif University of Technology Piri-Moghadam, Hamed (Author) ; Bagheri, Habib (Supervisor)

Abstract

In this thesis, a new approach was developed to achieve mechanical and chemical resistant capillary microextraction (CME) in on-line combination with high performance liquid chromatography (HPLC) based on sol-gel technology. This thesis is divided into three chapters:
First chapter contains of two parts. Overcoming the lack of mechanical stability of the substrate of CME by replacing the fused silica by copper tubings was the main objective of the first part. Self-assembled monolayers technique was employed to functionalize the copper tube followed by chemical bonding of the sorbent on the inner surface of the copper tube by sol-gel technology. The prepared copper tube containing the...

An approach for refining JML specification to object oriented code

, Article 2009 14th International CSI Computer Conference, 20 October 2009 through 21 October 2009 ; 2009 , Pages 1-9 ; 9781424442621 (ISBN) Piri, R ; Mirian Hosseinabadi, S. H ; Sharif University of Technology

2009

Abstract

JML is a behavioral interface specification language which has Java as its target implementation language. It combines the idea of using Java expressions from Eiffel language with the model-based approach to specify a program. Refinement calculus is a framework to produce executable code from a specification by preserving the correctness of programs. In this paper some constructs of JML concerning object creation, feature call, exceptional behavior and concurrency constructs are studied and some refinement rules are proposed to obtain an object oriented code in Java from a JML specification containig these constructs. The correctness of these rules is proved by weakest precondition predicate...

Simulation of the Influence of Hypertension on Low Density Lipoprotein (Ldl) Permeation into Multilayer Coronary Bifurcation

, M.Sc. Thesis Sharif University of Technology Moniri Piri, Mohammad (Author) ; Firoozabadi, Bahar (Supervisor)

Abstract

Atherosclerosis, due to the penetration of low-density lipoprotein particles (LDL) into the arterial wall, is one of the most common and death-leading diseases in today's world. Due to its importance, extensive research has been conducted on the factors that affect this disease. In this thesis, a numerical study of the effects of Wall Shear Stress (WSS), non-Newtonian behavior of blood, different hematocrit values, and blood pressure on LDL permeation through the artery wall layers are investigated in a 4-layer wall model of a coronary bifurcation. To obtain the velocity and concentration fields in the domain, momentum, Brinkman, and mass transport equations are solved in the lumen and wall...

Refning Object Oriented Formal Specifcation To Object Oriented Code

, M.Sc. Thesis Sharif University of Technology Piri, Razieh (Author) ; Mirian Hosseinabadi, Hassan (Supervisor)

Abstract

The presented work provides a calculus for refining an object oriented formal specification to an object oriented code. A refinement calculus provides a framework to produce executable code from a specification while preserving its correctness. Eiffel Refinement Calculus is the most complete work in this domain which is studied in this research.
The Formal specification language which is considered for this purpose is .JML to specify executable code in .Java language. For this calculus some refinement laws are pre- sented and their proofs is given by weakest precondition predicate transformer, a work which was not considered in Eiffel Refinement Calculus. The constructs which are used in...

On-line micro solid-phase extraction of clodinafop propargyl from water, soil and wheat samples using electrospun polyamide nanofibers

, Article Chromatographia ; Vol. 77, issue. 9-10 , May , 2014 , p. 723-728 Bagheri, H ; Asgari, S ; Piri-Moghadam, H ; Sharif University of Technology

2014

Abstract

An on-line extraction/determination set up was designed for micro solid-phase extraction of clodinafop propargyl from water, soil and wheat samples using electrospun polyamide nanofiber mats. The prepared mats were packed in a stainless steel tube which conveniently acted as a high-performance liquid chromatography injection loop. Influential parameters affecting the extraction efficiency were optimized using a distilled water sample fortified with 25 μg L-1 of clodinafop propargyl. An enrichment factor of 440 was achieved for clodinafop propargyl indicating the ability of the whole procedure. Under the optimum conditions, the linearity for the analyte was in the range of 6-700 μg L-1, while...

Grafting the sol-gel based sorbents by diazonium salts: A novel approach toward unbreakable capillary microextraction

, Article Journal of Chromatography A ; Volume 1318 , November , 2013 , Pages 58-64 ; 00219673 (ISSN) Bagheri, H ; Bayat, P ; Piri Moghadam, H ; Sharif University of Technology

2013

Abstract

The present work deals with a novel approach for grafting a sol-gel based sorbent, using diazonium salts for preparation of an unbreakable capillary microextraction (CME) device in on-line combination with high performance liquid chromatography (HPLC). The use of diazonium salts modifier allowed all types of metallic and non-metallic substrates to be used without any limitation. Substrates including copper, brass, stainless steel and polytetrafluoroethylene (PTFE) were chosen to be functionalized by chemical or electrochemical reduction of 4-amino phenyl acetic acid. Then, 3-(trimethoxysilyl)propylamine (3TMSPA) was selected as the precursor and the only reagent for preparation of the...

Wavelet Applications in Pattern Recognition

, M.Sc. Thesis Sharif University of Technology Piri Pishekloo, Bijan (Author) ; Mahdavi Amiri, Nezameddin (Supervisor)

Abstract

We study wavelet transformation for use in pattern recognition. Feature extraction is a crucial processing step for pattern recognition. Feature extraction is based on finding mathematical methods for reducing dimensionality of pattern representation. Two most important features to be extracted are edges and textures. Edges and textures are not absolute concepts and change with scale. Moreover, local characteristics of edges are needed. In recent decades, wavelet transformation as a mathematical tool has captured the attention of many scientists in signal processing and mathematics. Wavelet basis can provide efficient and useful description of a function or signal since it has local...

Risk Breakdown Structure (RBS) Identification and Designing for projects

, M.Sc. Thesis Sharif University of Technology Abdi, Mehdi (Author) ; Sepehri, Mehran (Supervisor)

Abstract

To actualize and making the outputs of a project effectual, it is necessary to conduct an effective management during a project. This case may not be possible without accurately planning for activities, management and controlling all phases of a project ignoring the risk management of that project. If risks of a project cannot be detected before conducting a project, it is possible to challenge the performance and even effectiveness of the project. In current conditions, the most important problem of managers and executives of construction projects through the country is risk management of projects, not acknowledging with definitions of risk, models of risk management and lack of a model for...

Distributed Cardiovascular System Modeling

, M.Sc. Thesis Sharif University of Technology Khani, Mehrdad (Author) ; Jahed, Mehran (Supervisor)

Abstract

Simulation of cardiovascular system functionality during various physiological conditions is essential at different diagnostic and clinical levels. A first step in studying the roots of cardiovascular diseases and abnormal activity is to study a practical yet complete model of the cardiovascular system. In this thesis we introduced a new approach for defining the distributed model of the cardiovascular system. Initially, we chose an appropriate subsystem, namely Arch of Aorta, and proposed a distributed model for it. The elements of the proposed model were nonlinear RLC elements that simulate resistance, blood viscosity and vessel elasticity respectively. To minimize the system complexity,...

Identifying Affecting HR Factors on Unsuccessful Reengineering Projects

, M.Sc. Thesis Sharif University of Technology Kordrostami, Melika (Author) ; Sepehri, Mehran (Supervisor)

Abstract

In this study, factors which lead in failures in reengineering processes in project based companies have been investigated. The research used qualitative methods, and finally using theme analysis to identify the main factors.Consequently, the main causes of failure of re-engineering projects have been identified and classified in six basic categories including: organizational leadership, planning, human resources management, mental models causing resistance, culture and organizational climate and communication. That each of these themes includes some subset of the agents it represents. In this study, a suitable pattern for organizations which intend to perform reengineering has been...

Performance Management of HSE Management System based on BSC Framework-the Case Study of Mapna Corporation

, M.Sc. Thesis Sharif University of Technology Naseri, Amin (Author) ; Sepehri, Mehran (Supervisor)

Abstract

A Balanced Scorecard (BSC) model is proposed to evaluate performance of Health, Safety and Environment (HSE) management systems. This model includes key performance indicators at three integrated levels. It has been tested and verified in a project-based organization in Iran, active in the area of power and energy. Results show that the company has done well in implementing HSE management processes, but no so well in growth and learning. This model may be used as a basis for comparing different companies and various proposed programs in the field of HSE management systems. The model includes indicators and sub-indicators in each category particularly related to stakeholders, processes, and...

Heat Transfer Modeling of Ultrasounic Hyperthermia

, M.Sc. Thesis Sharif University of Technology Heydari, Mohsen (Author) ; Jahed, Mehran (Supervisor)

Abstract

Ultrasound hyperthermia is a commonly used noninvasive approach to destroy cancer tumors. High Intensity Focused Ultrasound (HIFU) is a technique based on hyperthermia. It creates short and local elevations of temperature at a focus site within the tissue of interest. The main goal of HIFU is to maintain the temperature between 50 and 100 °C for a few seconds (typically less than 10 s), in order to cause tissue necrosis. In order to predict the effects of hyperthermia, accurate and effective modeling is needed. This study considers a 3D simulation of the hyperthermia based on HIFU method in the liver tissue. Temperature distribution and lesion volume changes, with a temperature of above...

Modeling Propagation of Cardiac Action Potential at Cellular Level

, M.Sc. Thesis Sharif University of Technology Farahani, Mojtaba (Author) ; Jahed, Mehran (Supervisor)

Abstract

Heartbeat is the result of contractions of over 10 billion cardiac cells. These cells’ cytoplasms are connected to each other by gap junctions which are arrays of intercellular protein channels. Thus action potential can propagate from one cell to another and cause its contraction. In core-conductor model, one-dimensional microscopic representation of cardiac tissue, cells are attached to each other to form a ladder network. The parallel elements are connected to each other by series resistors which represent gap junctions. These resistors are nearly always considered as static elements. In this thesis I have investigated the effects of incorporating the dynamicity of gap junction resistors...

Hand Posture Recognition through Stereo Vision System

, M.Sc. Thesis Sharif University of Technology Sangi, Mehrdad (Author) ; Jahed, Mehran (Supervisor)

Abstract

The mankind has always utilized vision as the most essential tool in evaluating his environment. Currently, one of the most important research areas in computer vision is to characterize a three dimensional object through its features in a natural scene. This task may be conducted through a stereo vision system. The objective of this study is to introduce a quantitative measure in order to evaluate the operation of an automatic recognition system for selected hand postures. A key application of our proposed system is to train a prosthetic hand through surface electromyogram (sEMG) signals. At the onset of this process, the patient conducts a certain posture through application of sEMG...

Joint Segmentation and Motion Estimation of Cardiac Cine MR Image Sequences

, Ph.D. Dissertation Sharif University of Technology Eslami, Abouzar (Author) ; Jahed, Mehran (Supervisor)

Abstract

In this study a variational framework for joint segmentation and motion estimation is provided for inspecting heart in Cine MRI sequences. In the first work, a functional including Mumford-Shah segmentation and optical flow based dense motion estimation is proposed. However, the motion estimation technique is replaced with warping estimation in the second work to reach in more regular and smooth motion field based on tracking of cardiac boundaries. Both of these functionals are then approximated by using the phase-field method to make them suitable for extracting Euler-Lagrange equations. Numerical solution to the optimization problem, when the time and image spaces are discretized by finite...

Automatic Hand and Wrist Motion Tracking and Assessment Using Stereo Vision and Video Processing

, M.Sc. Thesis Sharif University of Technology Safaei, Amin (Author) ; Jahed, Mehran (Supervisor)

Abstract

Gesture and motion evaluation are needed for a variety of applications. The use of human hand motions as a natural interface tool has motivated researchers to conduct research in the modeling, analysis and evaluation of various hand movements. In particular, human-computer intelligent interaction has been a focus of research in vision-based gesture recognition. In this work, we introduce a 3-D hand model evaluation method that offers flexible and elaborate representation of hand motion. We used landmarked points on tips and joints of the fingers and calculated the 3-D coordinates of these points through a stereo vision system followed by an HMM (Hidden Markov Model) to recognize hand...