, M.Sc. Thesis Sharif University of Technology Boraghi, Mahsa Sadat (Author) ; Parsafar, Gholamabbas (Supervisor)

Abstract

In 2009, a general equation of state (EOS-III) based on an effective near-neighbor pair interaction of an extended Lennard-Jones (3, 6, 12) type has been introduced as : , where is the compressibility factor, p and ρ stand for pressure and molar density , respectively, T is Temperature , and e, f and g are the temperature dependent coefficient of the equation of state . the Z_th and Z_in are the thermal and internal contributions of pressure in the compressibility factor, respectively. this equation of state gives a good description of all types of nano- and bulk –solid and bulk fluid at entire temperature and pressure ranges for which thee is experimental data. Investigation show that...

Photoelectrocatalytic Performance of Mesoporous TiO2 Nanostructures Decorated with Cu-Ag-Zn Particles for CO2 Conversion

, M.Sc. Thesis Sharif University of Technology Adel Rastkhiz, Mahsa Sadat (Author) ; Simchi, Abdolreza (Supervisor)

Abstract

The rise in carbon dioxide levels has led to the manifestation of numerous environmental challenges. Currently, the absorption and conversion of carbon dioxide into valuable fuel resources such as synthetic gas, methane, and ethylene are deemed crucial from both environmental and economic standpoints. Despite the presentation of photocatalysts such as titanium oxide and electrocatalysts such as copper, silver, and zinc, their efficiency in CO2 conversion is found to be insufficient. One potential solution to this problem is the utilization of photoelectrocatalytic CO2 recovery. In this study, the aim was to enhance the photoelectrocatalytic reduction of CO2 by designing and manufacturing...

Synthesis and Application of Preformed Viscoelastic Hydrogels in Enhanced Oil Recovery

, M.Sc. Thesis Sharif University of Technology Aqcheli, Farzad (Author) ; Taghikhani, Vahid (Supervisor) ; Baghban Salehi, Mahsa (Supervisor)

Abstract

Preformed particle gels (PPGs) due to its advatantage over commonly used in situ gels has been successfully applied for controlling excess water production in mature oil reservoirs. Field results of using PPGs in oil fields shows that commonly used PPGs are highly sensitive to hard reservoir conditions such as high temperature and salinity and can not effectively block fractures and high permeability layers.Objects of this study are synthesis and evaluating performance of this novel polymer based hydrogel in oil reservoirs with high temperature and salinity. Central composite design ( which is a experiment design approach) was used for synthesizing thirteen gel samples and optimal sample was...

Coating of Sewage Pipes with Appropriate Nanomaterials Aimed at Preventing Biological Growth (Algae+Biofilm)

, M.Sc. Thesis Sharif University of Technology Nezameddin, Mahsa Sadat (Author) ; Borghei, Mehdi (Supervisor) ; Ghasemi, Shahnaz (Co-Supervisor)

Abstract

Biological layers are one of the main problems related to water transfer with pipe lines which are formed through time in the inner surface of the pipes by the water nutrients. Hence, the inner surfaces in the pipe lines and water refineries should be made in order not to let these biological layers to be made. The reason is that when the biofilm is formed on these surfaces, the traversing water is polluted. Dredging of these pipes is not only necessary in most of the countries in the world and needs huge amounts of water but is also very complex and expensive.In this research, nanomaterials, namely ZnO, T〖iO〗_2،S〖iO〗_2 have been used to cover the surface of concrete and steel pipes (The...

Design and Manufacture of Polymeric Nanocomposite in Order to Control the Production and Migration of Sand in Reservoirs

, Ph.D. Dissertation Sharif University of Technology Saghandali, Farzin (Author) ; Taghikhani, Vahid (Supervisor) ; Baghban Salehi, Mahsa (Supervisor)

Abstract

Sand production from oil reservoirs leads to various problems, such as well productivity reduction, operating equipment corrosion, and increased production costs. Therefore, controlling sand production in unconsolidated reservoirs is crucial for operating companies. Chemical injection into the formation in order to strengthen and reduce sand production is one of the most important methods of sand control. In this study, a hydrogel nanocomposite was designed and its effectiveness in sand control was investigated. Various tests were carried out to define and assess its efficacy, as follows: Morphological tests demonstrated the creation of a dense, homogeneous, and porous structure. Structural...

Simultaneous Analysis of Aliphatic Alcohols Mixtures Using an Electronic Nose Based on Nano/Microstructured Conducting Polypyrrole Film Prepared by Catalytic Electropolymerization on Cu/Au Interdigital Electrodes Using Multivariate Calibration

, Article IEEE Sensors Journal ; Volume 16, Issue 2 , 2016 , Pages 418-425 ; 1530437X (ISSN) Alizadeh, N ; Babaei, M ; Alizadeh, M. S ; Mani Varnosfaderani, A ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2016

Abstract

In this paper, nano/microstructured-conducting polypyrrole has been prepared on Cu/Au interdigital electrode surfaces by using constant potential amperometry technique. The Fe(II) ions were used as catalyst and X = ClO4 -, pTs-, Cl-, TCA-, DS-, DBS- was implemented as anion dopants. The morphologies of the films were investigated by field emission scanning electron microscope. A remarkable dependence was observed between the type of anion dopant and the morphology of polypyrrole (PPy). The sensing behavior of the PPy-X sensor has been studied toward acetone, methanol, ethanol, 1-propanol, 2-propanol, nitromethane, propylamine, pyridine, and gas mixtures of aliphatic alcohols. The responses...

High performance grout connection for pre-cast concrete structures

, Article International Conference on Sustainable Construction Materials and Technologies, Coventry, 11 June 2007 through 13 June 2007 ; 2007 , Pages 479-485 ; 9780415446891 (ISBN) Alizadeh Kharazi, M ; Sharif University of Technology

2007

Abstract

Connections have very important role in pre-cast concrete structures, especially in seismic zones, and grout connections increase strength and resistance of pre-cast concrete structures for lateral forces. High performance grout connections (HPGC) provide new opportunities to design cost-effective pre-cast concrete structures. HPGC have been proposed to decrease cost of insulation, erection and crane cost of pre-cast concrete structures and to overcome weakness of traditional pre-cast concrete structure connections .This research focuses on properties of grout materials properties which produced in Iran and the effect of propylene fiber on the performance of grout connection. In the first...

Temperature dependence and the effect of charge configuration on water permeation through modified carbon nanotubes: A simulation study

, Article Fluid Phase Equilibria ; Volume 363 , 15 February , 2014 , Pages 282-289 ; ISSN: 03783812 Alizadeh, A ; Parsafar, G ; Sharif University of Technology

2014

Abstract

We have investigated the water permeation through carbon nanotube (CNT) membranes as a model of peptide nanotube channels (PNCs). The effect of different charge configured CNTs which tailored based on some artificial ion channels on the water permeation through the channels have been studied. In addition, the temperature dependence of the permeation has been investigated. We have found that there is a jump in the permeation which is somehow related to the characteristics of each channel and the temperature of this permeation jump changes according to the channel configuration. Our investigation on the channels shows that the temperature at which the permeation jump occurs is related to the...

Developing a model for citizens' satisfaction with public sector services based on rough sets theory: A case study of Tehran municipality

, Article Tehnicki Vjesnik ; Volume 20, Issue 5 , 2013 , Pages 795-802 ; 13303651 (ISSN) Alizadeh, A ; Kianfar, F ; Sharif University of Technology

2013

Abstract

Original scientific paper Developing a model for citizens' satisfaction with public services is one of the effective factors for improvement of service quality. In recent years, many studies have been carried out to identify a model for citizens' satisfaction with public sector services. In the structure of the presented models in the literature, one of the most important issues regarding organizations giving public services is identification of service scopes that have the most impact on citizens' satisfaction. This paper aims to develop a model to identify citizens' satisfaction status with public services. To do so, first, key factors influencing citizens' satisfaction with public...

On lob algebras, II

, Article Logic Journal of the IGPL ; Volume 20, Issue 1 , April , 2012 , Pages 27-44 ; 13670751 (ISSN) Alizadeh, M ; Ardeshir, M ; Sharif University of Technology

2012

Abstract

We study the variety of Löb algebras, the algebraic structures associated with Formal Propositional Calculus. Among other things, we show that there exist only two maximal intermediate logics in the lattice of intermediate logics over Basic Propositional Calculus. We introduce countably many locally finite sub-varieties of the variety of Löb algebras and show that their corresponding intermediate logics have the interpolation property. Finally, we characterize all chain basic algebras with empty set of generators, and show that there are continuum many such chain basic algebras

On Temperature Dependency of Delay for Local,Intermediate, and Repeater Inserted Global Copper Interconnects

, Article IEEE Transactions on Very Large Scale Integration (VLSI) Systems ; Volume 23, Issue 12 , 2015 , Pages 3143-3147 ; 10638210 (ISSN) Alizadeh, A ; Sarvari, R ; Sharif University of Technology

2015

Abstract

Cryogenic technologies not only improve the performance of interconnects but also the performance of transistors and consequently drivers and repeaters. Although in cryogenically cooled integrated circuits the local temperature of interconnects and transistors may be as low as 50 K, it may easily reach to 600 K in high-temperature chips. In this brief, we investigated the impact of temperature on the delay of local, intermediate, unit-repeater-inserted (URI), and cascaded repeater-inserted (CRI) global copper interconnects for minimum technology node with available transistor model (32-nm technology). Our results show that temperature variation of driver resistance could change the delay of...

A broadband integrated class-J power amplifier in gaas pHEMT technology

, Article IEEE Transactions on Microwave Theory and Techniques ; Volume 64, Issue 6 , 2016 , Pages 1822-1830 ; 00189480 (ISSN) Alizadeh, A ; Medi, A ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2016

Abstract

This paper presents a design methodology for class-J monolithic microwave integrated circuit (MMIC) power amplifiers (PAs). Theoretical derivations of optimum load impedances, output power, efficiency, and maximum bandwidth are described in presence of nonlinear drain-source resistance of transistors (RDS). A procedure is developed for ideal transistor sizing where transistors are concurrently stabilized and sized to achieve the maximum power-added efficiency (PAE). A 3.5-7 GHz, 0.5-W class-J PA is implemented in a 0.1-μm AlGaAs-InGaAs pHEMT technology to check the accuracy of the proposed approach. With chip dimensions of 1.57 × 1.29 mm2, the PA achieves 56% average PAE over the frequency...

Temperature-Dependent Comparison between Delay of CNT and Copper Interconnects

, Article IEEE Transactions on Very Large Scale Integration (VLSI) Systems ; Volume 24, Issue 2 , 2016 , Pages 803-807 ; 10638210 (ISSN) Alizadeh, A ; Sarvari, R ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2016

Abstract

The performance of gigascale integration chips improves by cryogenic technologies such as subambient cooling. In these conditions, interconnects may perform at temperatures as low as 50 K. However, the local temperature of interconnects could easily be as high as 600 K at high-temperature chips. In this brief, we investigated the impact of temperature on delay of local, intermediate, and global interconnects of International Technology Roadmap for Semiconductors Node 2024. This is done for different values of interconnect width and length, nanotube diameter, and percentage of metallic carbon nanotubes (CNTs) in a grown bundle. Results are compared with those of copper counterpart. We showed...

Fuzzy group decision making model for identifying and ranking of success factors in fraud prevention in Iranian e-banking

, Article Journal of Information Technology Management ; Volume 9, Issue 2 , 2017 , Pages 355-378 ; 20085893 (ISSN) Alizadeh, A ; Chehrehpak, M ; Sharif University of Technology

2017

Abstract

With increasing use of e-banking system in Iranian banking sector, ignoring the issue of fraud in the system will be very costly for banks and e-banking customers. Fraud in e-banking is due to some security problems (such as weakness in access control systems and inadequate internal control). So, identifying success factor in fraud prevention in ebanking can be useful for e-banking system developers to improve these systems security. In this paper we have tried to identify and rank these success factors for fraud prevention in e-banking systems. For this purpose, we first review the literature to find potential factors, then identified factors were weighted by using fuzzy group multi...

Basic propositional logic and the weak excluded middle

, Article Logic Journal of the IGPL ; Volume 27, Issue 3 , 2019 , Pages 371-383 ; 13670751 (ISSN) Alizadeh, M ; Ardeshir, M ; Sharif University of Technology

Oxford University Press 2019

Abstract

We study basic propositional logic (BPC) augmented with the law of the weak excluded middle (WEM), i.e. BPW = BPC+WEM. We show that the variety of the algebraic models of BPW is canonical, and its Kripke completeness is proved via cononicity. Moreover, it is also proved that BPW has the finite model property and is decidable. It is shown that BPC and BPW have the same behaviour on the ˔-free formulas and that CPC and BPW have the same behaviour on the negated formulas. © The Author(s) 2018. Published by Oxford University Press. All rights reserved

Compressed Domain Moving Object Detection Based on CRF

, Article IEEE Transactions on Circuits and Systems for Video Technology ; Volume 30, Issue 3 , 2020 , Pages 674-684 Alizadeh, M ; Sharifkhani, M ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2020

Abstract

This paper aims to present a novel accurate moving object detection method based on the conditional random field (CRF) for high efficiency video coding/H.265 compressed domain video sequences. For each block, the number of consumed bits, motion vectors (MVs), and partitioning modes for a given block is extracted from the compressed bitstream. After removing outlier MVs, compensating MVs are assigned to the I-blocks based on their neighboring blocks. The information, such as MV, partitioning mode, and bit consumption, is used in the potential functions of a CRF model which is updated for every frame to detect the objects. Then, a number of standard test video sequences are used to verify the...

A mechanistic study of emulsion flooding for mobility control in the presence of fatty acids: Effect of chain length

, Article Fuel ; Volume 276 , 2020 Alizadeh, S ; Suleymani, M ; Sharif University of Technology

Elsevier Ltd 2020

Abstract

Emulsion flooding is a promising method for enhanced oil recovery (EOR). The static and dynamic behavior of the emulsions is greatly influenced by the nature of the applied surfactant. In this work, the effect of fatty acids, as natural surface-active agents, and their chain length on the emulsion behavior was investigated in both bulk and porous media. A panel of the fatty acids with different chain lengths (6 < C < 18) was applied at constant concentration and pH. Upon the static stability tests, emulsion stability at the optimum value of chain length (C14) was increased by two orders of magnitude. Under the optimal condition, the hydrogen bonding between dissociated and undissociated...

Investigation of a class-j mode power amplifier in presence of a second-harmonic voltage at the gate node of the transistor

, Article IEEE Transactions on Microwave Theory and Techniques ; Volume 65, Issue 8 , 2017 , Pages 3024-3033 ; 00189480 (ISSN) Alizadeh, A ; Medi, A ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2017

Abstract

In this paper, performance of class-J mode power amplifiers (PAs) is studied when a second-harmonic voltage component is added to the input node of the device. Theoretical formulations for the optimum load impedances, output power, and drain efficiency are developed for this case, and it is shown that the inclusion of a proper second-harmonic voltage at the gate node of the transistor improves the drain efficiency and output power. To check the accuracy of the theoretical analyses and the simulation results, a proof-of-concept 1-GHz 0.65-W class-J PA is fabricated in a 0.25-μm AlGaAs-InGaAs pHEMT technology. The nonlinear gate-source capacitor (CGS) of the transistor is employed to generate...

Authors reply to comments on investigation of a class-j mode PA in presence of a second-harmonic voltage at the gate node of the transistor

, Article IEEE Transactions on Microwave Theory and Techniques ; Volume 66, Issue 7 , 2018 , Pages 3344-3344 ; 00189480 (ISSN) Alizadeh, A ; Medi, A ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2018

Distributed class-J power amplifiers

, Article IEEE Transactions on Microwave Theory and Techniques ; Volume 65, Issue 2 , 2017 , Pages 513-521 ; 00189480 (ISSN) Alizadeh, A ; Medi, A ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2017

Abstract

This paper presents the design and implementation of a distributed class-J power amplifier (DJPA) in a 0.25-μm AlGaAs-InGaAs pHEMT technology. Class-J mode of operation is introduced in design of distributed power amplifiers (DPAs) to achieve high power added efficiencies (PAEs) over wide frequency ranges. Extensive load-pull (LP) and source-pull (SP) simulations are performed to show that class-J PAs are less sensitive to proper termination of higher order harmonics, and high PAE and output power can be obtained even if the second, third, fourth, and fifth harmonics comprise a real impedance. This is essential in DPAs as the higher order harmonics of the frequencies at lower side of the...