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An algorithm for finding a feasible solution of graph labeling problems [electronic resource]
, Article Utilitas Mathematica Publishing Incorporated ; 2007, Vol. 72, pp. 163-174 ; Azimi, Parham ; Sharif University Of Technology
Abstract
Graceful labeling is one of the best known labeling methods of graphs. Despite the large number of papers published on the subject of graph labeling, there are few particular techniques to be used by researchers to gracefully label graphs. In this paper, first a new approach based on the mathematical programming technique is presented to model the graceful labeling problem. Then a “branching method” is developed to solve the problem for special classes of graphs. Computational results show the efficiency of the proposed algorithm for different classes of graphs. One of the interesting results of our model is in the class of trees. The largest tree known to be graceful has at most 27 vertices...
Applications of mathematical programming in graceful labeling of graphs [electronic resource]
, Article Journal of Applied Mathematics (Published by Hindawi) ; Vol. 10, No. 10, pp. 1-8 ; Azimi, Parham ; Sharif University of Technology
Abstract
Graceful labeling is one of the best known labeling methods of graphs. Despite the large number of papers published on the subject of graph labeling, there are few particular techniques to be used by researchers to gracefully label graphs. In this paper, first a new approach based on the mathematical programming technique is presented to model the graceful labeling problem. Then a “branching method” is developed to solve the problem for special classes of graphs. Computational results show the efficiency of the proposed algorithm for different classes of graphs. One of the interesting results of our model is in the class of trees. The largest tree known to be graceful has at most 27 vertices...
Conceptual Design and Study of Feasibility of a Compressed Air Driven Car
, M.Sc. Thesis Sharif University of Technology ; Durali, Mohammad (Supervisor)
Abstract
Using clean and renewable energy as driving force for vehicles is becoming more and more important because of rising fuel prices and also environmental concerns. Using solar and wind power for direct use in vehicles seems impractical with today’s technology. Compressed air can serve as an intermediate medium to store energy and utilize it for running vehicles. The main purpose of this research was to conceptually design an air driven vehicle with acceptable performance in a city for everyday life. After a brief history, at first step advantages and disadvantages of using air as driving force of vehicle is studied. This study was carried out in different categories including cost, capability...
Enhanced Photocatalytic Activity of Nano-scaled TiO2 Co-doped with N and Ag by Sol-gel Method
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor)
Abstract
Transparent coatings with self-cleaning property in visible light spectrum, UV radiation resistance and antimicrobial are highly desirable. Titanium dioxide (TiO2) is used in this research has been widely studied as an efficient photocatalyst by researchers. In this research enhanced visible-light photocatalytic activity is gained with N and Ag co-doped titania. All samples were annealed at 450℃. Finally AgI was loaded TiO2 coating and the results were investigated. Peaks of XRD pattern wereattributed to different diffraction planes of anatase TiO2. Morphology of coatings were analyzed with using FE-SEM. Nano granis size of TiO2 and AgI loaded TiO2 were observed in FE-SEMimages. Nitrogen...
Precise formulation of electrical capacitance for a cylindrical capacitive sensor
, Article Journal of Applied Sciences ; Volume 9, Issue 8 , 2009 , Pages 1556-1561 ; 18125654 (ISSN) ; Golnabi, H ; Sharif University of Technology
2009
Abstract
In this study a more precise formulation of electrical capacitance for a cylindrical capacitive sensor is reported. By using different theoretical models such as Coulomb law, Gauss law and Laplace equation the electrical capacitance is calculated. Based on the given models the relation between the capacitance and the geometrical parameters (e.g., cylindrical length) is formulated and by using suitable software capacitance variation is computed and compared for different methods. In Coulomb method, the electrical potential is first solved numerically by using Mathematica and then the electrical capacitance is computed. It is found that the active capacitor length is crucial parameter in the...
Investigation of Dust Emission Paths Over Lake Urmia Local Dust Spots Using the HYSPLIT Model
, M.Sc. Thesis Sharif University of Technology ; Tajrishy, Masoud (Supervisor)
Abstract
At Lake Urmia (LU) greatest extent, it was the largest lake in the Middle East and the sixth-largest saltwater lake on Earth, with a surface area of approximately 5,200 km2. The lake has shrunk to 10% of its former size due to damming of the rivers that flow into it, and the pumping of groundwater from the surrounding area. Moreover, as the lake shriks its potentional to be a major dust sources increases. A Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model was used to investigate and track the extent of dust emission and aerosol concentration over Lake Urmia marginal dust spots in order to identify the affected and critical areas. Also, percent movement, propagation...
Integrated Drilling Oprations Optimization
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Saeid (Supervisor)
Abstract
Drilling Operations constitute more than fifty percent of total costs of well construction operations. Due to this fact, optimization of drilling operations could have significant effect on decrease in total costs of well construction. It is mentioning worthy that there are a variety of parameters which affect drilling operations from the view point of optimization. In many cases several of those aforementioned parameters are contrary in nature. Thus obtaining an integrated approach to optimize the operation by considering these effects is necessity. The goal of this thesis is to investigate different influential parameters of drilling operation optimization and to develop computer-based...
Effect of the Blast Furnace Slag on Microstructural and Transport Properties of the Fly Ash-based Geopolymers
, M.Sc. Thesis Sharif University of Technology ; Toufigh, Vahab (Supervisor)
Abstract
Alkali-activated fly ash-slag (AAFS) is a new type of sustainable construction material widely studied in recent years for its desirable mechanical properties and low environmental impacts. In this study, the effects of the slag incorporation from 10 to 30% of fly ash are investigated on the strength, pore structure, and transport properties of the AAFS with various levels of fly ash replacements with slag. The unconfined compression and ultrasonic pulse velocity tests were performed to evaluate the mechanical properties of the AAFS concrete. Microstructural and mineralogical changes were studied by porosity, N2-adsorption/desorption, and SEM/EDX tests. Additionally, transport properties...
Experimental and Numerical Study of Spray Combustion under Hot-diluted Conditions
, M.Sc. Thesis Sharif University of Technology ; Mardani, Amir (Supervisor)
Abstract
In this thesis, combustion of liquid fuel spray under the condition of hot and diluted oxidizer, has been investigated. To this end, a novel type laboratory-scale test rig was designed to study the physics governing the MILD-Spray combustion conditions with an applied approach. The underlined test rig eliminates the operational problems of its predecessor test stands and is used for a heavier fuel with much more complex chemical composition (kerosene). The test section is axially symmetrical, in which the fuel is injected by a pressure-swirl atomizer in the direction of hot and diluted co-flowing air. With the use of the aforesaid test rig, the effect of variables such as oxygen...
A new algorithm to solve sinusoidal steady-state Maxwell's equations on unstructured grids
, Article Scientia Iranica ; Volume 25, Issue 3B , 2018 , Pages 1296-1302 ; 10263098 (ISSN) ; Saidi, M. S ; Sharif University of Technology
Sharif University of Technology
2018
Abstract
A new approach for attaining numerical solution to sinusoidal steady-state Maxwell's equations is developed. This approach is based on Yee's method, and can be applied on unstructured grids. A problem is solved by the method and the results show good agreement with the available analytical solution. This method can be improved to be applicable for general unsteady problems. © 2018 Sharif University of Technology. All rights reserved
Enhancement of brick-mortar shear bond strength using environmental friendly mortars
, Article Construction and Building Materials ; Volume 195 , 2019 , Pages 28-40 ; 09500618 (ISSN) ; Toufigh, V ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Usage of masonry system in many regions of the world like the Eastern Mediterranean, the Middle East, India, and China is still significantly high, despite their highly energy and intensive emission. Most of the failures in this system are caused by low ductility of cement mortars. This type of failure could be seen in masonry structures in areas in east Iran after Kermanshah earthquake in 2017. The present study investigates the shear bond characteristics of structures constructed by masonry using green materials. “Taftan” natural pozzolan and two types of rice husk ash (RHA) were used in mix design of used mortars as green materials. In this investigation, a modified direct shear test...
Using Decoupling Techniques in Control of Fractional-Order TITO Systems
, M.Sc. Thesis Sharif University of Technology ; Tavazoei, Mohamad Saleh (Supervisor)
Abstract
The purpose of this thesis is presenting some decoupling methods for fractional-order two input-two outputs (TITO) systems in order to using in control applications. To achieve this purpose, some methods which have been proposed for decoupling of integer-order systems have been studied and then generalized to be used in decoupling of the fractional-order systems. These methods are classified in two classes: state space based methods and transfer function based methods. Also, in this thesis the proposed decoupling methods have been used in control of some fractional-order TITO systems
Estimation of Network Parameters for use in Congestion Control Algorithm
, M.Sc. Thesis Sharif University of Technology ; Jahangir, Amir Hossein (Supervisor)
Abstract
Many congestion control protocols proposed so far to alleviate the problems encountered by TCP protocol in high-speed networks and wireless links have to estimate the parameters of the network. For example, the TCP WESTWOOD congestion window is adjusted based on available bandwidth estimation, or TCP Vegas detects the congestion status based on RTT (Round Trip Time) estimation, and XCP protocol operates according to network traffic load. In this paper, we proposed a novel estimation algorithm that is based on burst identification techniques in router. we show through analysis and simulation that during burst periods this method can estimate the congestion window size of the specific flow...
Evaluation of Effect of Phreatic Line Level on Stability of Uupstream Tailings Dams
, M.Sc. Thesis Sharif University of Technology ; Pak, Ali (Supervisor)
Abstract
Tailings dams are considered as one of the most important geotechnical structures and due to the large amount of contaminated tailings deposited behind the dam, any failure of these structures, apart from loss of lives and properties, can be an environmental disaster. Researches show that most of the failure incidents in the last few decades have happened in tailings dams constructed using upstream method. As a result, it is of great significance to study the stability of upstream tailings dams.
The place of the phreatic line in the dam body plays a critical role in stability of tailings dams. Soil-atmosphere interaction effects such as precipitation, runoff, interception, infiltration,...
The place of the phreatic line in the dam body plays a critical role in stability of tailings dams. Soil-atmosphere interaction effects such as precipitation, runoff, interception, infiltration,...
Quality assessment of gasoline using comprehensive two-dimensional gas chromatography combined with unfolded partial least squares: A reliable approach for the detection of gasoline adulteration
, Article Journal of Separation Science ; Volume 39, Issue 2 , 2016 , Pages 367-374 ; 16159306 (ISSN) ; Mostafapour, S ; Azimi, G ; Sharif University of Technology
Wiley-VCH Verlag
2016
Abstract
Comprehensive two-dimensional gas chromatography and flame ionization detection combined with unfolded-partial least squares is proposed as a simple, fast and reliable method to assess the quality of gasoline and to detect its potential adulterants. The data for the calibration set are first baseline corrected using a two-dimensional asymmetric least squares algorithm. The number of significant partial least squares components to build the model is determined using the minimum value of root-mean square error of leave-one out cross validation, which was 4. In this regard, blends of gasoline with kerosene, white spirit and paint thinner as frequently used adulterants are used to make...
Investigation of dynamics and vibration of a three unit pig in oil and gas pipelines
, Article 2008 ASME International Mechanical Engineering Congress and Exposition, IMECE 2008, Boston, MA, 31 October 2008 through 6 November 2008 ; Volume 11 , 2009 , Pages 265-275 ; 9780791848722 (ISBN) ; Fazeli, A ; Azimi, M ; Sharif University of Technology
2009
Abstract
In this paper, the transient motion of a three unit intelligent Pipe Inspection Gauge (PIG) while moving across anomalies and bends inside gas/oil pipeline has been investigated. The pipeline fluid has been considered as isothermal and compressible. In addition, the pipeline itself has also been considered to be flexible. The fluid continuity and momentum equations along with the 3D multi body dynamic equations of motion of the pig comprise a system of coupled dynamic differential equations which have been solved numerically. Pig's position and velocity profiles as well as upstream and downstream fluid's pressure waves are presented as simulation results which provide a better understanding...
Patterned and disordered continuous abelian sandpile model
, Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 80, Issue 4 , 2009 ; 15393755 (ISSN) ; Moghimi Araghi, S ; Sharif University of Technology
2009
Abstract
We study critical properties of the continuous Abelian sandpile model with anisotropies in toppling rules that produce ordered patterns on it. Also, we consider the continuous directed sandpile model perturbed by a weak quenched randomness, study critical behavior of the model using perturbative conformal field theory, and show that the model has a random fixed point. © 2009 The American Physical Society
Analytical and Experimental Studies on Interface between Different Mortars and Brick
, M.Sc. Thesis Sharif University of Technology ; Toufigh, Vahab (Supervisor)
Abstract
Usage of masonry materials in a country like Iran is still significantly high. As most of the failures during an earthquake in this system is failure caused by low ductility of cement mortars and also the high rate of carbon dioxide produced by cement. Experiences of Kermanshah earthquake in 2017 in Iran has doubled the importance of this issue. Hence, in the present investigation, an attempt to enhance the shear bond characteristics of structures constructed by masonry using green materials has been made. “Taftan” natural Pozzolan and two types of rice husk ash (RHA) was used in mix design of used mortars as a green material. In this investigation, a direct shear test (DST) device is...
Simulation of Competitive Flow in the Coronary Arteries Bypass
,
M.Sc. Thesis
Sharif University of Technology
;
Firoozabadi, Bahar
(Supervisor)
Abstract
Atherosclerosis is one of the most important factors for mortality and morbidity in the world. Coronary artery bypass graft (CABG) is applied for treatment of this disease which in this surgery, the patient vessels, such as internal thoracic artery and saphenous vein, are harvested and grafted to the coronary arteries. The graft success and its performance in short and long-term are depended on the much factors e.g. the severity of stenosis in the coronary artery. It should be noted that the low level of stenosis in the coronary artery causes the creation of undesirable phenomenon of competitive flow in the grafts after the surgery which this phenomenon has been reported as a cause of graft...
A Closed-Loop Model for Green Blood Supply Chain Considering Supply and Demand Uncertainty
, M.Sc. Thesis Sharif University of Technology ; Akhavan Niaki, Taghi (Supervisor)
Abstract
Blood is a very valuable material for the life of human beings and should be transfused to the patient as soon as possible in case of necessity. It is s perishable product and different blood products have different shelf lives. Therefore, it is important to manage properly blood product inventories in hospitals to avoid shortage and outdate as much as possible. In this research, a bi-objective mixed-integer programming model is developed which aims to simultaneously minimize the total cost of the supply chain network and the total environmental impacts of the activities of the supply chain network. Since the nature of the problem is uncertain, a robust possibilistic programming approach is...