Investigation of Fracture Behavior of Geopolymer Concrete

, M.Sc. Thesis Sharif University of Technology Karamian, Mohammad Hossain (Author) ; Toufigh, Vahab (Supervisor)

Abstract

Geopolymer concrete is one of the most environmentally friendly concretes that does not have any pollutants harmful to the environment. By-products that are normally harmful to the environment can be used in manufacturing this product, therefore, the use of this concrete is known as the first concrete replacement in the world. In order to use geopolymer concrete, it is necessary to an essential to know the mechanical information of these materials.In this study, the mechanical behavior of geopolymer concrete for fly ash and slag in terms of its stress and strain uniaxial loading and triaxial loading at , and15MPa pressures for three concrete mixing design are investigated.Then the...

Harvesting Energy from Magnetic Shape Memory Alloys in Plannar Loading

, M.Sc. Thesis Sharif University of Technology Karamian Manesh, Mohammad Javad (Author) ; Sayyadi, Hassan (Supervisor)

Abstract

Harvesting energy by magnetic shape memory alloy has many advantages against other various methods which harvested from environmental vibrations and has been considered due to high long longevity, large strain amplitude and good performance in low frequencies. These materials can display up to % recoverable strain in response to the application of a magnetic field or compressive mechanical stress. Microstructure of these materials changes under applying mechanical loading and/or magnetic field which cause magnetic vector rotating in magnetic domain. Change in magnetization of these materials, lead to harvesting energy by considering Faraday's law of induction. The model of this...

Developing a Base Guideline for Cost Engineering System in Iranian Oil, Gas & Petrochemical Industry Projects

, M.Sc. Thesis Sharif University of Technology Majdian, Mohammad Ali (Author) ; Eslami, Hossain (Supervisor)

Analysis of Cohesive Crack Via Reproducing Kernel Particle Method (RKPM)

, M.Sc. Thesis Sharif University of Technology Mohammad Nataj, Milad (Author) ; Shodja, Hossain (Supervisor)

Abstract

The aim of this work is to study a cohesive crack in an elastic solid with meshless method. The procedure uses Reproducing Kernel Particle Method (RKPM) formulation in conjunction with Penalty method for implementing all constraints, including the Essential Boundary Conditions (EBCs) and the constraints related to cohesive crack. Meanwhile subdomain technique is employed to diminish the compiling process to facilitate one. Study of Stress Intensity Factor (SIF) at the tip of the cohesive crack has also been dealt with particular interest

Experimental Investigation of Pulsating Heat Pipe Using Nano-Fluid

, M.Sc. Thesis Sharif University of Technology Taslimifar, Mehdi (Author) ; Saidi, Mohammad Hassan (Supervisor) ; Afshin, Hossain (Supervisor) ; Shafiee, Mohammad Behshad (Supervisor)

Abstract

Considerable increase in speed and decrease in size of electronic devices results in increase of heat flux, so there is a need to enhance efficiency of cooling electronic devices. In the present research two sets of OLPHPs with five turns for two different magnetic nano-fluids were fabricated and the effects of working fluid (water, and two types of magnetic nano-fluids), working pressure, concentration, magnetic field, magnets location, and inclination angle on the thermal performance of OLPHPs have been considered in both startup and steady thermal conditions.
Experimental results show that magnetic nano-fluids can improve thermal performance of the OLPHPs. Application of magnetic...

Mechanical and metallurgical properties of dissimilar AA6061-T6 and AA7277-T6 joint made by FSW technique

, Article International Journal of Advanced Manufacturing Technology ; Volume 86, Issue 9-12 , 2016 , Pages 2551-2565 ; 02683768 (ISSN) Mohammad Aliha, M. R ; Shahheidari, M ; Bisadi, M ; Akbari, M ; Hossain, S ; Sharif University of Technology

Springer-Verlag London Ltd 2016

Abstract

Aluminum 6xxx and 7xxx series are among the most commonly used alloys in industrial applications whereas their joining and welding using conventional fusion-based weld processes are very difficult. In this paper, friction stir welding process of dissimilar AA6061-T6 and AA-7277-T6 aluminum plates was investigated. The effects of tool travers and rotational speeds and the type of material located in the advanced side (AS) or retreating side (RS) of weldment were studied experimentally on the mechanical and metallurgical characteristics of the joint. Macro- and microstructure pictures of weld region were used to evaluate the quality of the weld and defect detections. Tensile strength tests and...

Preparation and Investigation of Properties of Zirconia Coatings on Zirconium Substrate by MAO Method

, M.Sc. Thesis Sharif University of Technology Zareian, Shayan (Author) ; Faghihi Sani, Mohammad Ali (Supervisor) ; Kokabi, Amir Hossain (Supervisor)

Abstract

Zirconium is one of the most applicable metals in the production of chemical materials’ industry due to its great corrosion resistance. Coating method of microarc oxidation is a novel method to manufacture oxide coatings on metal substrates. Lots of studies have been done on the creation of these coatings on light metals such as Aluminum, Magnesium and Titanium hitherto; however, there is a scarcity regarding manufacture of zirconium oxide on zirconium metal via MAO method. In the current study, aiming to create proper zirconia coatings on zirconium substrate, firstly, by the change of process parameters like current waveform, electrolyte concentration, current density, time and frequency,...

A comparative evaluation of the additional impact of nanometer-sized tetravalent oxides on the performance of doloma-magnesia ceramic refractories

, Article Ceramics International ; Volume 44, Issue 2 , 2018 , Pages 2058-2064 ; 02728842 (ISSN) Ghasemi Kahrizsangi, S ; Gheisari Dehsheikh, H ; Karamian, E ; Nemati, A ; Sharif University of Technology

Elsevier Ltd 2018

Abstract

In this research study, a comparative evaluation of the additional impact of nanometer-sized tetravalent oxides [Zirconia (ZrO2), Titania (TiO2), and Silica (SiO2)] on the properties and performance of Doloma-Magnesia (MgO-CaO) ceramic refractories, with an emphasis on their hydration resistance improvement, has been done. For this purpose, from 0 to 2.5 wt% ZrO2, TiO2, and SiO2 nanometer-sized particles have been added to the Doloma-Magnesia compositions. After formulation and mixing of the starting materials, the pressed samples (at 150 MPa) were tempered (at 250 °C for 12 h) and fired in a shuttle furnace (at 1650 °C for 3 h). The physical, mechanical, and thermo-mechanical properties of...

An Integrated Land-Use and Transportation Model for the Evaluation of Urban Development Decisions

, M.Sc. Thesis Sharif University of Technology Ghiasi, Amir (Author) ; Poorzahedy, Hossain (Supervisor)

Abstract

Land-use and transportation are inter-related, such that land-use may be used to control transportation. This study aims to design a suitable combination of the residential and service land-use on one side, and the transportation system on the other side. The model presented in this study has two external and internal levels, and its objective is to minimize the cost of residence, receiving goods and services, and transportation. The performance of any combination of spatial allocation of population and employment, as well as transportation, is evaluated by the internal level of the model which determines the interaction between population, employment, and transportation. This is done by a...

Network Reconstruction for Emergency Response Following a Major Earthquake: Definition and a Solution Algorithm

, M.Sc. Thesis Sharif University of Technology Tayarani, Mohammad (Author) ; Poorzahedy, Hossain (Supervisor)

Abstract

Natural phenomena, such as earthquakes, floods, and hurricanes, have been, and will be, one major source of mankind disastrous problems. Mankindinterventions to relieve this heavy pressure on humanity have been divided into four categories: mitigation, preparedness, response, and recovery. This study is in the response phase, and aims to find an optimal network to help people in the devastated part of a city, hit by a major earthquake. Such earthquakes demolish buildings over the people inside, causing them fatal harm and serious injuries. At the same time, they ruin the city infrastructures (life lines), including transportation networks, preventing flow of relief supply to reach to the...

Integrated Road Reopening and Disaster Relief Programming: Problem Formulation and Solution Procedure

, M.Sc. Thesis Sharif University of Technology Dabiri, Sina (Author) ; Poorzahedy, Hossain (Supervisor)

Abstract

This research deals with the joint problem of reopening the roads closed after a disastrous natural event and the damaged area relief programming. While these two problems are connected to each other by the joint resources of ruins and debris removal, they are usually treated separately in the literature, and their solutions are sought in practice by the art of experienced authorities. This study formulates a dynamic tri-level integer programming problem to represent the two problems of Road Reopening and Relief, in which the crisis manager has the objective of minimizing the death tolls over a planning time interval. It identifies the roads for reopening at the first level; and the second...

A Solution for Network Design Problem by B.O.T (Build-Operate-Transfer) and Considering Uncertain Parameters of the Problem

, M.Sc. Thesis Sharif University of Technology Qiam, Shirin (Author) ; Poorzahedy, Hossain (Supervisor)

Abstract

Governments are concurrently faced with two problems in Network Development Problem (NDP): limited resources to invest, and the economic justification of the candidate projects. Public- Private Participation (PPP) is a solution for the first problem, in which Build- Operate- Transfer (BOT) is a scheme to implement this partnership.This study formulates a NDP, in which two sources of funds back projects’ construction: that of the private investor and the public budget for this purpose. The problem is seen as bi-level optimization, with the upper level dealing with the government decisions on the level of participation (from 0 to 100 percent of the project costs), and the lower level being a...

Application of a Multi-agent Optimization Model in Pre-disaster Planning with Consideration of Overall Loss: Case of Bam 2003 Earthquake

, M.Sc. Thesis Sharif University of Technology Asgharpour, Sina (Author) ; Poorzahedy, Hossain (Supervisor)

Abstract

Earthquake is one of the deadliest natural hazards that has taken more than 400 thousand lives, only in the last decade. Iran is one of the countries that are at high risk of potential death toll resulting from such hazards, firstly because it is located in a potentially high-risk zone, the so-called earthquake belt and, secondly because of its problems in the management of disastrous situations (especially, pre-disaster management). Bam 2003 earthquake is one of the most painful experiences in this context. So, in this research, emphasizing on the practical use of optimization models, an existing model is applied on the damaged area of the Bam earthquake. The mentioned model considers the...

Multi-criteria Multi-class Traffic Assignment Using Mixed Generalized Extreme Value Models

, M.Sc. Thesis Sharif University of Technology Shahhoseini, Zahra (Author) ; Poorzahedy, Hossain (Supervisor)

Abstract

Relaxing the underlying assumptions of transportation networks analysis and approaching to more realistic behavioral assumptions in route choice modeling, allows more precise predictions for equilibrium traffic pattern. Furthermore, enhancing the degree of sensitivity in modeling traffic equilibrium is crucial from planning perspective in the sense that it can make transportation analyst capable to evaluate and predict the impacts of a broad spectrum of supply and demand management policies. This research has concentrated on proposing some generalizations in route choice behavior modeling and relaxing some restrictive assumptions of the previous approaches in this area. Formally speaking, in...

Estimating Traffic Flow in Urban Networks with Day-To-Day Travel Time Fluctuations

, M.Sc. Thesis Sharif University of Technology Torkjazi, Mohammad (Author) ; Poorzahedy, Hossain (Supervisor)

Abstract

Variations in supply and demand of transportation, as well as those in the related environment, would cause daily variations in user travel time of transportation networks. This phenomenon particularly happen in morning travel time peaks, and make estimation of travel time highly unreliable. Morning peak passengers, whose timely presence at the destinations are highly important to them, prefer to choose paths that have minimum travel time and maximum reliability. Thus, the look at travel time pessimistically, and based on their experience, they put a margin of reliability to reach at timely at their destinations.
This study analysis such reliability margins based on the standard...

Recovery of Gold Electronic scraps(PCB) By Hydrometallurgical process

, M.Sc. Thesis Sharif University of Technology Zolfaghari, Sanaz (Author) ; Yozbashizadeh, Hossain (Supervisor)

Abstract

Increasing demand for Gold in electronic devices and catalysts, and its high cost, makes it crucial to recover the Gold from waste electronic devices such as Printed Circuit Boards. In this research, recovery of Gold by hydrometallurgical process based on heating the scraps along with a strong oxidizing agent, Potassium Persulphate, which is “eco-friendly” or “green”process is concerned. Recovery of Gold achieved by simple filtration process following by washing with water and nitric acid in order to dissolve impurities such as Al and Sn. The systematical and analytical evaluation method of Taguchi quality engineering has been applied for the leaching to evaluate the optimal experimental...

Horseradish peroxidase immobilization on amine functionalized carbon nanotubes: direct electrochemistry and bioelectrocatalysis

, Article Progress in Reaction Kinetics and Mechanism ; Volume 37, Number 2 , 2012 , pp. 161-172 Tasviri, M. (Mahboubeh) ; Ghourchian, H. (Hedayatollah) ; Gholami, M. R. (Mohammad Reza) ; Rafieepour, H. A. (Hossain Ali) ; Sharif University of Technology

2012

Abstract

Horseradish peroxidase (HRP) was successfully immobilized on amine functionalized TiO2-coated multiwalled carbon nanotubes (NH2 – TiO2 – CNTs) by a convenient and efficient method. Electrochemical impedance spectroscopy, cyclic voltammetry and amperometry were applied to characterize the HRP/NH2 – TiO2 – CNT nano-composite. These techniques showed that the NH2 – TiO2 – CNTs greatly enhance the electron transfer between HRP and the modified electrode. Owing to the redox reaction of the electroactive centre of HRP, the HRP = NH2 – TiO2 – CNTs modified electrode exhibited a pair of quasi-reversible peaks with a peak-to-peak separation (ΔEp) of 70.6 mV and a formal potential (E 0′) of 367.65 mV...

Numerical Modeling of Two Interacting Circular Holes Using a Gradient Elasticity Based Meshless Method

, M.Sc. Thesis Sharif University of Technology Ramhormozian, Shahab (Author) ; Mohammadi Shoja, Hossain (Supervisor)

Abstract

A theory of gradient elasticity is used and numerically implemented by a meshless method that is called reproducing kernel particle method (RKPM) to model size effects. Some of the problems are modeled under the consideration of gradient elasticity for the first time and all of them are also modeled with classical elasticity to compare with gradient elasticity. First of all, the RKPM formulation and computing the amount of shape functions and requisite derivatives will be explained with details and a mathematical innovation that will decrease the computational cost seriously proposed for the first time. Several 1D and 2D shape functions with first and second derivatives that are resulted...

Approximate Transportation Network Reliability Measures for Solving Transportation Network Improvement Problem

, M.Sc. Thesis Sharif University of Technology Iranitalab, Amirfarrokh (Author) ; Poorzahedy, Hossain (Supervisor)

Abstract

Long-term effects of natural disasters, like earthquakes, in many cases have been reported high on transportation networks. Disruption in this lifeline network's performance imposes high social and economic costs upon the society. Undoubtedly, retrofitting the structures of all network links (or constructing new links) are practically impossible and economically infeasible. One solution to this problem is finding a method for determining the network's important links, and retrofitting their structures. Based on this concept, an optimization problem of network performance improvement under these stochastic events is introduced. In this problem, a link importance index for network links is...

A Hybrid Meta-Heuristic Algorithm to Solve Three Dimensional Highway Alignment Optimization Problem

, M.Sc. Thesis Sharif University of Technology Faghih, Sabiheh Alsadat (Author) ; Poorzahedi, Hossain (Supervisor)

Abstract

There are several algorithms in the literature to solve the problem of finding an optimal path between two points in a region. Such path satisfies certain constraints while optimizing the objective function. There are many factors in building, or finding, such paths in the real world, whose considerations complicate the solution procedure. This led the researchers to seriously consider meta-heuristics to solve the problem. This study hybridizes several suitable and effective meta-heuristic algorithms to solve the routing problem on a given topography. In this hybrid meta-heuristic algorithm an Ant System finds a horizontal path between the two points under considerations on the topography. A...