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faghih--ahmad-reza
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A Fuzzy Multi-Criteria Approach to Sustainable Development Case Study of Hendurabi Island in Iran
,
Ph.D. Dissertation
Sharif University of Technology
;
Abrishamchi, Ahmad
(Supervisor)
;
Maknoon, Reza
(Co-Supervisor)
Abstract
The main objective of this research is to provide a framework by which decision-makers can evaluate and compare alternatives for sustainable development planning under uncertain dynamic future considering the risk and uncertainty associated with human judgment as well as the uncertain future. This approach combines the Delphi method, fuzzy set theory, and a discrete multi-criteria method based on prospect theory (TODIM). TODIM (an acronym in Portuguese for iterative MCDM) method is a particular multi-criteria approach based on the prospect theory. A qualitative Delphi technique is used to identify a set of qualitative sustainability criteria and to rate the alternatives accordingly. The...
Fabrication and Characterization of Porous Carbon-Graphene Composite as an Absorbent for Industrial Pollutants
, Ph.D. Dissertation Sharif University of Technology ; Madaah Hosseini, Hamid Reza (Supervisor) ; Pourjavadi, Ali (Supervisor) ; Bahramian, Ahmad Reza (Co-Supervisor)
Abstract
The amount of fresh water suitable for various uses is decreasing day by day. This may be due to evaporation or contamination of water or such. Heavy metal cations, dyes, oils and solvents are the most important substances that contaminate water. There are various ways to remove these contaminants, one of which is the absorption of these substances by suitable absorbents. Carbon compounds have attracted much attention among all the absorbents used so far. The aim of this study is to produce carbon aerogels from an economic and modify its structure and properties by adding graphene nanosheets. In this study, Novalak-graphene oxide (GO) gel was fabricated using solvent-saturated vapor...
Time series analysis framework for forecasting the construction labor costs
, Article KSCE Journal of Civil Engineering ; Volume 25, Issue 8 , 2021 , Pages 2809-2823 ; 12267988 (ISSN) ; Gholipour, Y ; Kashani, H ; Sharif University of Technology
Springer Verlag
2021
Abstract
This manuscript presents a framework to develop vector error correction (VEC) models applicable to forecasting the short- and long-run movements of the average hourly earnings of construction labor, which is an essential predictor of the construction labor costs. These models characterize the relationship between average hourly earnings and a set of explanatory variables. The framework is applied to develop VEC forecasting models for the average hourly earnings of construction labor in the USA based on the identified variables that govern its movements, such as Global Energy Price Index, Gross Domestic Product, and Personal Consumption Expenditures. More than 150 candidate VEC models were...
Cooperative security administration in multi-security-domain environments using a variant of deontic logic
, Article Scientia Iranica ; Volume 19, Issue 3 , June , 2012 , Pages 635-653 ; 10263098 (ISSN) ; Jalili, R ; Ehsan, M. A ; Faghih, F ; Sharif University of Technology
2012
Abstract
The decentralized approach to security administration in new computing environments (e.g., pervasive computing and mobile environments) is based on apportioning the environment into multiple security domains. The security policies of each security domain are specified by an authority and enforced by a security agent. The requirements of cooperative administration in such Multi-Security-Domain (MSD) environments, for shared or subdomains, induced us to propose an MSD cooperation framework within a logical security policy language (called MASL) in this paper. MASL is a variation of deontic logic that enables multiple authorities to specify their domain policies, including obligations and...
Human Capital Development and Utilization Methodology in a Public Sector Organization: Dynamic Capability Approach
, M.Sc. Thesis Sharif University of Technology ; Kermanshah, Ali (Supervisor) ; Sanjari, Ahmad Reza (Supervisor)
Abstract
It is proposed, in this research, a methodology for a public sector organization to integrate policy making in human capital development and utilization area. In this case the researcher used system dynamics method for modeling and analyzing the situation, to describe the mechanisms that produce the difficulties in the organization. The researcher mentioned the differences between public sector and profit organization, in designing the main part of the model and also the use of dynamic capability approach in designing human capital development parts of it. The model built in this research, describe the events before and after the 1990s separately, according to the different policy making...
Optimal Asset Allocation with Hidden Markov Regime Switching
,
M.Sc. Thesis
Sharif University of Technology
;
Bahramgiri, Mohsen
(Supervisor)
;
Jalali Naeni, Ahmad Reza
(Supervisor)
Abstract
Asset allocation is one of the core economic functions of security markets. By purchasing and selling securities individuals are able to effectively time their stream of consumption and to allocate their temporarily unused wealth among competing investments. To time the stream of future consumption optimally, the question arises as to how wealth is allocated most effciently on security markets. The purpose of this thesis is to develop an optimal Asset Allocation with Hidden Markov Regime Switching means and volatilities. We use the historical weekly information of three Indices in Wallstreet stock exchange: Stock, bond and commodity. First we use these historical information from...
Improvement and Expansion of Characteristic Green’s Function-Complex Images Method for Extraction of Green’s Function of Finite Dielectric Structures
, Ph.D. Dissertation Sharif University of Technology ; Shishegar, Amir Ahmad (Supervisor) ; Faraji-Dana, Reza (Co-Advisor)
Abstract
Finite dielctric structures are commonly used in optical devices, Microwave Integrated Circuitc (MICs) and printed antennas. To analyze these structures, full-wave analysis methods cannot be employed easily. They need huge computer resources and are time-consuming especially for electrically large structures. On the other hand, asymptotic techniques may not be exact enough for these structures. In this thesis, MPIE technique is chosen as an accurate and efficient technique for analyzing these structres. To use this technique, the magnetic vector potential and electric scalar potential are required. Uniform and closed-form spatial Green's function for finite dielectric structures is...
Design and Control of Handspring Robot Using Geometric Control
, M.Sc. Thesis Sharif University of Technology ; Alasti, Aria (Supervisor) ; Salarieh, Hassan (Supervisor)
Abstract
Living creatures have a significant ability to move on various surfaces and to pass obstacles and because of this many robots have been made by inspiring their moving mechanisms. One of these mechanisms that is sometimes ignored because of its nonlinear dynamics and instability and hybrid dynamics of system, is jumping mechanism. In this project a two dimensional multi-legged jumping robot is designed that can jump, do a handspring during jump and land on its other side keeping balanced. The robot moves forward by repeating such procedure. Doing a handspring instead of normal jump uses less energy.This robot uses geometric control method to handspring during flight. This method ables robot...
Simulation of GTL Process Slurry Bubble Column Reactor Using CFD Methods
, Ph.D. Dissertation Sharif University of Technology ; Bozorgmehri, Ramin (Supervisor) ; Pishvaie, Mahmoud Reza (Supervisor) ; Tavassoli, Ahmad (Co-Advisor)
Abstract
In this thesis non-ideal behavior of fluids and its effects on hydrodynamic and mass transfer in multiphase flow is studied. A numerical framework has been proposed to model the interacting effects of mixture non-ideality and mass transfer on hydrodynamics of a multiphase system using CFD methods. Using the numerical framework mass and momentum transfer in a system was simulated. The system consists of a cylindrical vessel filled with vapor and liquid hydrocarbons which selected as the benchmark. The liquid hydrocarbon is chosen to be pure Octane and the hydrocarbon in the gas phase is assumed to be Propane. Due to operating condition (T=323 K, P =445 kpa) the behavior of fluid is non-ideal...
Preparation of Biodegradeble Nanocomposite with Appropriate Physical and Mechanical Properties for Bread Packaging
, M.Sc. Thesis Sharif University of Technology ; Ramezani Saadat, Ahmad (Supervisor) ; Mohammadi, Mohammad Reza (Supervisor)
Abstract
Platelet nanoparticles could dramatically decrease permeability of polymeric film where increase considerably its physical -mechanical properties. Bio based (Biodegradable) polymeric materials such as starch based polymeric films show very weak mechanical and high oxygen and water vapor permeability. Graphene oxide (GO) could increase mechanical properties of starch based polymer where decrease its permeability dramatically. Addition of chitosan also could increase antibacterial and antifungal of films and decrease permeability of films considerably. In this research nanocomposite of Starch/Chitosan/GO films have been prepared by solution method and its morphology, permeability, physical...
Effect of tiO_2 Nanoparticles on Heat and Drag Properties of Dilute Polymer Solutions
, M.Sc. Thesis Sharif University of Technology ; Ramezani Saadat Abadi, Ahmad (Supervisor) ; Mohammadi, Mohammad Reza ($item.subfieldsMap.e)
Abstract
In the present work, the experiments were carried out for two types of PAM (3330 and 3630) with three distinct concentrations (25, 40 and 55 ppm) and TiO_2-water nanofluid for four concentrations (1.5, 2, 2.5 and 3 vol. %), and the Nusselt number and friction factor for each of them expressed separately. The Reynolds number was in the range from 11000 to 21000. The steady state turbulent convective heat transfer and friction factor of the combination of TiO_2-water nanofluid and polymer 3330 in the coiled tube were investigated. The effects of the Reynolds number for 2 vol. % nanoparticles which consists of 25 ppm PAM (3330) determined at the constant temperature of 24°C. It was observed...
Cosmology with Polarization of Gravitational Waves
, M.Sc. Thesis Sharif University of Technology ; Baghram, Shant (Supervisor) ; Mansouri, Reza (Supervisor)
Abstract
the gravitational wave (GW) which is a prediction of General Relativity has entered a new era after being detected by Ligo observatory in 2015. new discoveries are still being made. the discovery of GW is a new opportunity for studying gravity, astrophysical sources of GWs like binary black-holes or binry neutron stars as well as testing cosmology models.on the other hand, it should be mentioned that the astronomy of gravitational waves is in its dawn stage. in future having numerous precise detectors and by accumulation of data, speaking about exact phenomena and statistical analysis will become meaningful. as in the case of cosmic microwave background physics, in which researchers started...
Manufacture of Smart Drug Delivery System with UCST Polymers
, M.Sc. Thesis Sharif University of Technology ; Ramazani, Ahmad (Supervisor)
Abstract
Smart heat-sensitive polymers play a unique role in drug delivery systems due to reversible behavior in response to environmental changes, especially temperature changes. Among the heat-sensitive polymers, UCST polymers due to their specific behavior and very little-known polymers with this feature are the subject of many new researches. In the present study, New designed temperature-sensitive polymers with UCST capability based on acrylamide and vinyl acetate were synthesized. These copolymers were synthesized in different percentages of acrylamide by free radical polymerization in solution conditions. All polymers compounds were characterized by H-NMR, FT-IR, DSC and GPC measurements. The...
Optimization of Operational Parameters for a Semi-continuous Compost Unit
, M.Sc. Thesis Sharif University of Technology ; Shayegan, Jalal (Supervisor) ; Kariminia, Hamid Reza (Co-Advisor) ; Yusofzadeh, Ahmad (Co-Advisor)
Abstract
The sudden increase in population growth rate in major cities and the recent changes in life style (consumerism) have resulted in a massive load of municipal solid waste. Managing this huge amount of waste imposes a heavy burden on municipalities’ shoulders. There are several options to Manage Solid waste, among them incineration and landfill are widely use in Managing municipal solid waste. Considering the fact that these two options are potentially hazardous to environment, high moisture content of municipal solid waste added, composting has become more trendy approach in last decades.Although composting is more environmentally friendly, it still needs the waste to be collected from all...
Designing Instruction Prefetcher with Low Area Overhead for Server Workloads
,
M.Sc. Thesis
Sharif University of Technology
;
Sarbazi Azad, Hamid
(Supervisor)
;
Lotfi Kamran, Pejman
(Co-Supervisor)
Abstract
L1 instruction cache misses creates a crucial performance bottleneck for server applications. Server applications extensively use operating system services, and as such, have large instruction footprint that dwarfs instruction cache size. Meanwhile, fast access requirements preclude enlarging instruction cache that can hold the whole instruction footprint of current server workloads. Prior works proposed using hardware prefetching schemes to eliminate or reduce the effect of instruction cache misses. They use the fact that server application instruction sequences are repetitive. So by recording and prefetching based on such sequesnces, L1 insruction misses could be reduced. While they...
Numerical study of lorentz force interaction with micro structure in channel flow
, Article Energies ; Volume 14, Issue 14 , 2021 ; 19961073 (ISSN) ; Ali, K ; Ahmad, S ; Cai, J ; Sharif University of Technology
MDPI AG
2021
Abstract
The heat transfer Magnetohydrodynamics flows have been potentially used to enhance the thermal characteristics of several systems such as heat exchangers, electromagnetic casting, adjusting blood flow, X-rays, magnetic drug treatment, cooling of nuclear reactors, and magnetic devices for cell separation. Our concern in this article is to numerically investigate the flow of an incompressible Magnetohydrodynamics micropolar fluid with heat transportation through a channel having porous walls. By employing the suitable dimensionless coordinates, the flow model equations are converted into a nonlinear system of dimensionless ordinary differential equations, which are then numerically treated for...
Study of Nanocrystallization Kinetics, Microstructure and Magnetic Properties of Finemet-type Soft Magnetic Materials
, Ph.D. Dissertation Sharif University of Technology ; Madaah Hosseini, Hamid Reza (Supervisor) ; nozad, Ahmad (Supervisor) ; Beitollahi, Ali (Co-Advisor)
Abstract
Nanocrystallization kinetics of amorphous Finemet-type alloys was studied using Isokinetic and Isoconversional methods (Kissinger model-fitting method, Vyazovkin advance method, Kissinger–Akahira–Sunose(KSA),Flynn–Wall–Ozawa(FWO),Tang and Starink) under isothermal and non-isothermal conditions. Effects of chemical composition on the nanocrystallization kinetics, microstructure and magnetic properties of Fe73.5Si13.5B9Nb3Cu1 and Fe77Si11B9Nb2.4Cu0.6 alloys were also investigated. Kinetic triplet (activation energy, frequency factor and reaction model) were determined by these methods and compared for the alloys. According to isoconversional methods, the activation energy is variable as a...
Preparation, Evaluation and Investigation of NiO-MgO-SiO2 Catalyst Deactivation in Propane Reforming
, Ph.D. Dissertation Sharif University of Technology ; Frahadi, Fathollah (Supervisor) ; Kazemeini, Mohammad (Supervisor) ; Rezaei, Mehran (Supervisor) ; Keshavarz, Ahmad Reza (Co-Supervisor)
Abstract
Synthesis gas (H2, CO) is widely used in chemical and petrochemical industries, utilized for methanol and ammonia production. Hydrogen is the main component of syngas which is considered as an appropriate alternative for fossil fuels. Catalytic steam reforming is one of the most common and economical pathway for syngas production. Light hydrocarbons such as propane which can easily be transported, stored and distributed, is a promising feed candidate for steam reforming. Catalyst deactivation along with low stability resulting from carbon formation and sintering is one of the main crucial problems in this process, leading to much research on the preparation of stable and coke resistant...
Experimental Investigation of New Polymers for Enhanced Oil Recovery from one of the Iranian Oil Reservoirs
, M.Sc. Thesis Sharif University of Technology ; Ramazani Saadatabadi, Ahmad (Supervisor) ; Masihi, Mohsen (Supervisor) ; Ghazanfari, Mohammad Hossein (Supervisor) ; Rasaei, Mohammad Reza (Co-Advisor)
Abstract
Polymer flooding is a famous enhanced oil recovery method and is used to reduce mobility ratio of displacing fluid to displaced fluid by forming a stable front in displacing process. Due to high costs, polymer flooding faces economical risks and from this point of view, performance investigation of polymer flooding in laboratory scale was concerned. In this project, performance of 7 types of polymers which have different rheological properties were investigated in fractured/non-fractured carbonated and sandstone reservoirs. These polymers consists of 4 commercial polymers, one branched polymer, one synthetic polymer and one polymer composite which have different molecular weight,...
A self-similar approach to study nanofluid flow driven by a stretching curved sheet
, Article Symmetry ; Volume 14, Issue 10 , 2022 ; 20738994 (ISSN) ; Jamshed, W ; Ahmad, S ; Bashir, H ; Ahmad, S ; Tag El Din, E.S.M ; Sharif University of Technology
MDPI
2022
Abstract
Nano-fluids have considerable importance in the field of thermal development that relates to several industrial systems. There are some key applications in recent construction systems flow, as well as microscale cooling gadgets and microstructure electric gadgets for thermal migration. The current investigation concludes the study of electrically conducting nano-fluid flow and heat transfer analysis in two-dimensional boundary layer flow over a curved extending surface in the coexisting of magnetic field, heat generation and thermal radiation. The small sized particles of copper (Cu) are taken as nanoparticles and water is assumed to be the base fluid. We used quasi-linearization and central...