Modeling of Enhanced Geothermal Systems Using XFEM Technique

, M.Sc. Thesis Sharif University of Technology Rezaie Beydokhti, Omid (Author) ; Khoei, Amir Reza (Supervisor)

Abstract

In this study, a fully coupled thermo-hydro-mechanical model for modeling Enhanced geothermal systems (EGS) is introduced using the extended finite method for numerical solution. Enhanced geothermal systems are fractured porous media that in addition to the solid phase usually consist of one or more fluids. Heat extraction from Enhanced geothermal systems involves several Multiphysics coupling processes, including the seepage flow through the fractured porous media, the thermal exchange between the working fluid and the matrix, and the deformation of fractured porous media. modeling of these processes is complex and has several parameters. Therefore, a thermal-hydraulic-mechanical (THM)...

Modeling enhanced geothermal systems using a hybrid XFEM–ECM technique

, Article Applied Thermal Engineering ; Volume 230 , 2023 ; 13594311 (ISSN) Mortazavi, M. S ; Rezaie Beydokhti, O ; Khoei, A. R ; Sharif University of Technology

Elsevier Ltd 2023

Abstract

Heat extraction from Enhanced Geothermal Systems (EGS) involves several multi-physics coupling processes, including the seepage through the fractured porous media, the thermal exchange between the working fluid and the matrix, and the deformation of fractured porous media, which play essential roles in exploiting the geothermal energy contained in hot dry rocks. In this study, a fully coupled numerical model for Thermo-Hydro-Mechanical simulation of EGS is presented based on the local thermal non-equilibrium using the eXtended Finite Element Method (XFEM) and Equivalent Continuum Method (ECM). The ECM can provide the equivalent tensors of not only fluid permeability but also solid...

Optimization of Raw Material Inventory Control System in Khorramshahr Oil Extraction Company Based on ( r,Q ) Optimal Inventory Policy

, M.Sc. Thesis Sharif University of Technology Rezaie, Mojtaba (Author) ; Hajji, Rasool (Supervisor)

Abstract

This thesis is related to applying survey of scientific inventory control methods in Khoramshahr Oil Extraction Company (KHOEC). KHOEC is the producer of edible oils in I.R of Iran and is a subset of E.T.K.A holding organization. The inventory costs of high consuming items are studied and optimized based on the optimal ordering policy (r, Q). First, the company raw materials are identified and classified based on ABC analysis method. For developing the new method of inventory control, the demand for each item is predicted, and the probability distribution of demand during the lead time is determined. Then according to this information and the desired service level of management, order point...

A Mechanism Design Approach to Solve A Crowdsourcing Problem

, M.Sc. Thesis Sharif University of Technology Rezaie, Maryam (Author) ; Ghodsi, Mohammad (Supervisor)

Abstract

Nowadays, we observe the growth in the number of mobile smart phones. These smart phones have had an impressive progress in software and hardware. Many studies have focused on utilizing this new platform. One of these areas of research is collecting information from environment.Two major challenges for a successful crowdsourcing system are engaging a sufficient number of workers and validating of their registered data, which make the system more reliable. Collecting data from different points of a territory can be defined as some tasks and should be assigned to users near those tasks properly. Some users want a monetary reward for the cost they incur. On the other hand, information...

Configuration Design in Scalable Reconfigarable Manufacturing Systems (RMS)

, M.Sc. Thesis Sharif University of Technology Rezaie Baghbadorani, Parham (Author) ; Houshmand, Mahmoud (Supervisor)

Abstract

The dynamic nature of today’s manufacturing industry, which is caused by the intense global competition and constant technological advancements, requires systems that are easily adaptable with new functions and technologies. In fact, a highly responsive manufacturing system is needed in which, introducing new products, adjusting system capacity with demand fluctuations and integrating new technologies with the existing ones are quickly possible.Reconfigurable Manufacturing systems (RMS) are a relatively new paradigm in industry that enable rapid adjustments of production capacity to changes in product mix and volume through their main characteristics including modularity, scalability and...

Designing a Framework for Power Exchange in Local Energy Market of a
Microgrid Using the Concept of Blockchain Technology

, M.Sc. Thesis Sharif University of Technology Rezaie, Farhad (Author) ; Moeini Aghtaee, Moein (Supervisor)

Abstract

By entering the concepts of transactive energy systems, microgrids and peer-to-peer networks into the local energy market, it has made it possible to implement local energy market in the microgrids more than ever. In transactive energy systems, with the elimination of the intermediate entity, exchanges take place directly between the different parts of the system, which results in increased system flexibility and reduced system costs. In this study, by applying blockchains in local energy market and in micro-grids and transactive energy systems, a framework is proposed to implement local energy market in an energy micro-grid based on blockchain. By using blockchain features and structure,...

Electrochemical sensors based on functionalized carbon nanotubes modified with platinum nanoparticles for the detection of sulfide ions in aqueous media

, Article Journal of Chemical Sciences ; Volume 131, Issue 3 , 2019 ; 09743626 (ISSN) Mohajeri, S ; Dolati, A ; Salmani Rezaie , S ; Sharif University of Technology

Springer 2019

Abstract

Abstract : Vertically aligned carbon nanotube (CNT) arrays were synthesized by thermal chemical vapor deposition (CVD) on stainless steel substrates coated by cobalt nanoparticles as catalyst. Morphological and elemental analyses conducted by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) revealed that bamboo-like CNTs were blocked by Co nanoparticles at the tips. The fabricated nanotubes underwent functionalization by electrochemical oxidation in sulfuric acid, and the subsequent structural studies, as well as Fourier transform infrared (FTIR) spectroscopy confirmed that the tips of functionalized CNTs were opened while oxygenated functional groups were...

Hydrogen management in refineries: Retrofitting of hydrogen networks, electricity and ammonia production

, Article Chemical Engineering and Processing - Process Intensification ; Volume 157 , 2020 Rezaie, F ; Roshandel, R ; Hamidi, A. A ; Sharif University of Technology

Elsevier B.V 2020

Abstract

In this paper, hydrogen management in refineries is examined considering a new perspective to optimize refinery costs. In order to minimize the total annual cost in refineries a mixed-integer non-linear programming (MINLP) model has been developed. Retrofitting the hydrogen network and determining the hydrogen surplus capacity of refineries are the main outputs of the proposed model. Then, to utilize this surplus capacity and increase the profitability of refineries, surplus hydrogen is used to produce electricity and ammonia. The results of a case study showed that retrofitting of the hydrogen network can save 12% in the consumption of fresh hydrogen from hydrogen plants. After retrofitting...

Realization of constant envelope OFDM using quantization and CPM technique

, Article AEU - International Journal of Electronics and Communications ; Volume 80 , 2017 , Pages 172-178 ; 14348411 (ISSN) Rezaie, S ; Mohammadi, A ; Afrashteh, N ; Sanjaroonpouri, V ; Sharif University of Technology

2017

Abstract

Orthogonal frequency division multiplexing (OFDM) is used in many wireless communication. The important drawback of this modulation is its high peak-to-average power ratio (PAPR). In this paper, a new modulation scheme of constant-envelope OFDM (CE-OFDM) is proposed. This scheme uses a combination of OFDM, quantizer and continuous phase modulation (CPM) to achieves 0 dB PAPR. The statistical signatures of signals, based on system parameters such as the length of discrete Fourier transform (DFT) and the number of quantization levels are presented. There are two sources of noise in proposed CE-OFDM scheme: quantization noise and channel noise. The theoretical analysis of these noises is...

Modified distributed mediation device for low power consumption in large scale sensor networks

, Article 2nd International Conference on Intelligent Sensing and Information Processing, ICISIP'05, Chennai, 4 January 2005 through 7 January 2005 ; Volume 2005 , 2005 , Pages 7-12 ; 0780388402 (ISBN); 9780780388406 (ISBN) Shahmansouri, V ; Ghannad Rezaie, M ; Pakravan, H. R ; Sharif University of Technology

2005

Abstract

This paper proposes a new medium-access control (MAC) protocol designed for wireless sensor networks. A wireless sensor network is an array of large number of sensors interconnected by a multi-hop ad-hoc network. The fundamental objective for sensor network is low-power consumption while latency is usually less important. This characteristic of sensor network motivates different MAC laver design from the conventional wireless network to reduce power consumption. In this paper novel algorithm based on distributed mediation device (DMD) protocol has been introduced that utilized distributed node scheduling strategy to dramatically increase energy saving principally in intermediate devices...

Adaptive fault-tolerant data flooding for energy-aware sensor networks

, Article 2nd International Conference on Intelligent Sensing and Information Processing, ICISIP'05, Chennai, 4 January 2005 through 7 January 2005 ; Volume 2005 , 2005 , Pages 83-87 ; 0780388402 (ISBN); 9780780388406 (ISBN) Karzand, M ; Ghannad Rezaie, M ; Shah Mansouri, V ; Sharif University of Technology

2005

Abstract

Flooding technique is widely using to manipulate sensor network essential activities such as synchronization, data gathering, network query and in-network information processing. Reliable and low latency data broadcasting is the primary goal in design of appropriate quality of service aware flooding algorithm. This paper proposes a new error-rate adaptive reliable data flooding strategy. Energy consumption which it the main limitation in sensor network, has been considered in optimal presented scheme. Also the tradeoff between reliability, power consumption and latency has been cared to achieve the finest devise. The simulation results have shown significant enhancement in quality of data...

Particles in the early Universe: Interface of Cosmology and Particles Massive Neutrinos and Cosmology

, M.Sc. Thesis Sharif University of Technology Rezaie, Mehdi (Author) ; Golshani, Mehdi (Supervisor) ; Farzan, Yasaman (Supervisor)

Abstract

Neutrino flavor oscillations are clear evidence of massive neutrinos. It has been for more than a decade that neutrino physics became one of active topics in the field of particle physics and various experiments started studying the flavor oscillation of neutrinos. Unfortunately, experiments studying the flavor oscillations are only sensitive to the mass square difference, and they are incapable of providing more information about the absolute mass scale of neutrinos. Additionally, sterile neutrinos having non-standard interactions are under vast investigations and studies. Determination of neutrino masses and their effective number is among the most challenging problems by which...

Application of Process Control Charts to Improvement of Survival Time of Patients with Gastric Cancer

, M.Sc. Thesis Sharif University of Technology Rezaie Jahan, Hamid Reza (Author) ; Mahlooji, Hashem (Supervisor)

Abstract

Statistical process control charts have been applied to the health care practices for quite same time. This work aims at investigating the merits to of applying process control chart to the survival time of the patients suffering from gastric cancer-who go though the surgical treatment. Based on accelerated failure time regression models we adopt risk adjusted control chart to monitor the surgical outcome. The monitoring process will we performed continuously based on a likelihood ratio test. The result indicate that this risk adjusted model can provide better estimation for the risk adjustment model parameters. As expected, the proposed risk-adjusted control charts can achieve a better...

Comparative Study of Gasoline and Ethanol Combustion in a SI Engine Combustion Chamber Using Closed Cycle CFD Simulation

, M.Sc. Thesis Sharif University of Technology Rezaie, Milad (Author) ; Hosseini, Vahid (Supervisor) ; Shafie, Behshad (Supervisor)

Abstract

At today’s crowded world, the importance of automobile transportation is obvious for all. The fossil fuel pollution crisis has increased the need for renewable-fueled engines with higher efficiency and lower emissions. Meanwhile, biofuels have received more attention for reasons such as carbon dioxide cycling, Affordability and availability. However, despite these benefits biofuels require crops such as corn or potatoes to produce, which in turn produce other environmental pollution. On the other hand, concerns have been raised as to whether the use of these fuels increases the amount of other pollutants, except for carbon dioxide, or not. Extensive researches in this field by experimental,...

Synthesize of Graphene Nanoribbons with a Non-Zero Energy Band Gap for Inactivation of Alive Cells Using Infrared Irradiation

, M.Sc. Thesis Sharif University of Technology Emamy, Hamed (Author) ; Akhavan, Omid (Supervisor)

Abstract

Graphene is a one layer atom thickness and zero energy gap so for using it in nano electronic and transistors baised on graphene it's energy gap should be opened.one of the methods for opening graphene band gap is creating nano scale boundaries or synthesize graphene nanoribbons. One of the new methods for graphene nanoribbon synthesize is longitudinal opening of carbon nanotube. In this thesis graphene nanoribbons synthesize with this method and analyze with AFM and Raman spectroscopy. Carbon nanotubes also have energy gap and IR absorption recently they used for living cell destruction. In this thesis we synthesize graphene nanoribbons and analyzing their optical absorption and use it for...

Fabrication of Graphene/TiO2 Nanowalls as Visible Lights Photocatalysts

, M.Sc. Thesis Sharif University of Technology Rahimi, Kourosh (Author) ; Akhavan, Omid (Supervisor)

Abstract

TiO2 is known as a photocatalyst in near UV-Visible light region with better efficiency compared to other semiconductor photocatalysts. Many attempts have been done to increase the efficiency of this photocatalyst. also, application of 2D carbon nanostructures namely graphene for increasing the photocatalytic activity of TiO2 has shown positive results.
In this research, we first synthesized Graphene Oxide (GO) suspension by exfolation of graphite oxide suspension. then we fabricated TiO2 thin films on glass substrates by so-called sol-gel method. finally we fabricate Graphene Oxide/TiO2 nanowalls composite films as a photocatalyst in visible light. X-ray photoelectron spectroscopy...

Fabrication of Graphene-WO3 Nanocomposites as Photocatalyst in the Visible Light Region

, M.Sc. Thesis Sharif University of Technology Choobtashani, Mohammad (Author) ; Akhavan, Omid (Supervisor)

Abstract

WO3 is known as a photocatalyst in the visible light region, but with lower efficiency compared to more interesting semiconductor photocatalysts such as TiO2 and ZnO. Many attempts have been done to increase the efficiency of this photocatalyst by incorporating metal and metal oxide nanoparticles or recently carbon nanotubes.On the other hand, application of graphene, as an unrolled carbon nanotube, for increasing the photocatalytic activity of TiO2 and ZnO has shown positive results. Furthermore, it was reported that such semiconductor photocatalysts (and very recently WO3) can photocatalytically reduce the chemically exfoliated graphene oxide sheets under UV-vis irradiation.
In this...

Synthesis of Graphene Nanosheets for Stem Cells Applications

, M.Sc. Thesis Sharif University of Technology Shahsavar, Mahla (Author) ; Akhavan, Omid (Supervisor)

Abstract

Graphene nanogrids fabricated by graphene nanoribbons obtained through oxidative unzipping of multi-walled carbon nanotubes, used as two-dimensional selective templates for accelerated differentiation of human mesenchymal stem cells (hMSCs), isolated from umbilical cord blood, into osteogenic lineage. The biocompatible and hydrophilic graphene nanogrids showed high actin cytoskeleton proliferations that coinciding with patterns of the nanogrids. The amounts of proliferations found are slightly better than proliferation on hydrophilic graphene oxide (GO) sheets, and significantly higher than non-uniform proliferations on hydrophobic reduced graphene oxide (rGO) sheets and polydimethylsiloxane...

Identifying the risks of Iranian Knowledge BasedFirms Using Fault Tree Analysis (FTA)

, M.Sc. Thesis Sharif University of Technology Sarhadi, Maryam (Author) ; Fattahi, Omid (Supervisor)

Abstract

Knowledge Based Firms are considered to be important for the economic development of a country in regards to both employment growth and innovative activity. The latter is believed to contribute significantly to the increase in productivity and therefore the competitiveness of Iran’s economy. This study contributes to the above literature by investigating the factors that are believed to treat the growth of such firms in Iran. The purpose of this study is to identify functional risks of vital signs monitors via Fault Tree Analysis (FTA) method to use as a guide for manufacturers to identify and control hazards. Therefore, 30 knowledge based firms were selected as sample. Then, based on a...

Synthesis of Graphene from Waste by Chemical Exfoliation and Study of It’s Physical Characteristics

, M.Sc. Thesis Sharif University of Technology Mirsepah, Ali (Author) ; Akhavan, Omid (Supervisor)

Abstract

One atom thick layer of pure carbon in bonded and hexagonal lattice is named graphene. graphene has unique mechanical, optical, thermal and electrical properties and because of these properties has grabbed attention. graphene has been made from high pure graphite by different methods such as CVD(chemical vapor deposition) , chemical exfoliation , micromechanical cleavage and colloidal suspension. through these methods, green methods for synthesis of graphene, using eco-friendly reductants during synthesis of graphene instead of hydrazine and recently using waste(not graphite) are attractive for synthesis of graphene. Following this idea , a group has produced graphene from wastes such as...