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nanotechnology
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Feasibility Study of Application of Developing New Techniques for Fuel Cell Vehicle by Focusing on Nanotechnology
, M.Sc. Thesis Sharif University of Technology ; Mostafavi, Mostafa (Supervisor)
Abstract
Due to daily decrease of fossil energy resources, increase of environmental pollution which is included of toxic and greenhouse gases, and extensive growing rate of demands in transportation industry, especially vehicle industry, developing solutions in using fuel cells are vital for this industry in our country. Fuel cells are green, efficient and also powerful energy generators. According to potential advantages of fuel cells, structure, performance, benefits and also types of fuel cells are introduced as a desired energy resource. Indentifying existing choices of energy generators and ranking them using MCDM (Multi-Criteria Decision Making) technique was the first step to perform a...
The Comparative Study of Nanotechnology Research and Development in The World Selected Countries
, M.Sc. Thesis Sharif University of Technology ; Ghasemi, Farhad (Supervisor)
Abstract
Nanotechnology requires a number of infrastructures for reaching its sustainable development. For each step of its development , various infrastructures should be studied and prepared in advance.In this direction, by introducing and recognizing the priority of Iran Nanotechnology R&D indexes ,the present research is going to propose an effective help. In this case, after studying the related literature and gathering the needed data , 27 indexes were recognized. Then , the indexes were divided in 7 criteria.In order to find the priority of the applied indexes , Fuzzy Multiple Criteria Decision Making (FMCDM) was applied. As the weighting of 7 criteria had been found by FANP , the...
Preparation of Membrane Humidifier using Nanotechnology to Humidify Hydrogen and Oxygen in Fuel Cells
, M.Sc. Thesis Sharif University of Technology ; Roosta Azad, Reza (Supervisor) ; Moosavi, Abbas (Supervisor)
Abstract
Polysulfone (PSU) and polyethersulfone (PES) porous membranes; and mixed polymers (PSU and PES) with nanoparticles TiO2, were prepared for air humidification. The mechanical properties and morphology of these membranes were studied by Tensile Tester and SEM/EDX. The effects of membrane composition and operating factors on humidifier performance were investigated. The results revealed that the membrane composition and its structure have significant effect on humidification. The porous membranes with finger type cavities had higher humidification performance but lower mechanical properties. The Membranes which were prepared from polysulfone polymer, 10 wt % of polymers in casting solution and...
Transistor Based on Graphane
, M.Sc. Thesis Sharif University of Technology ; Khorasani, Sina (Supervisor)
Abstract
In the recent years, field effect transistor has been made by using graphane. But there has not been any study about bipolar transistor. Bipolar transistor can’t be constructed using graphene due to the fact that its band gap is zero. So in this thesis, in an attempt to remove this difficulty, the bipolar transistor made using graphane has been investigated and their property has been compared to those of three dimensional silicon transistors.
At the beginning of the thesis, we will have a review of graphane diode and will consider the procedure for evaluating its current which would be the report of what has been done sofar. After that we made graphane transistor using graphane diode...
At the beginning of the thesis, we will have a review of graphane diode and will consider the procedure for evaluating its current which would be the report of what has been done sofar. After that we made graphane transistor using graphane diode...
Investigation on Coupling of Molecular Dynamics Method and Temperature Related Cauchy Born Methods
, M.Sc. Thesis Sharif University of Technology ; Kazemi, Mohammad Taghi (Supervisor)
Abstract
Computational Nano Mechanics growth has led researchers towards the development of new multi-scale models. Accordingly, in this dissertation, a step was taken towards introduction, presentation and creation of a new concurrent multi-scale by studying the feasibility of coupling of molecular dynamics methods and temperature related Cauchy-born.To do so, firstly, the above mentioned methods have been studied and then in order to perform molecular dynamics simulations, a program written in C++ language has been used. The accuracy of the written code has been confirmed through studying intuitive phenomenon of gas perfect particle exit from cylinder with an open end. The interpretation of out put...
Reliability Improvement in 3D Network-on-chips Against Crosstalk Fault
, M.Sc. Thesis Sharif University of Technology ; Miremadi, Ghassem (Supervisor)
Abstract
Technology node scaling in recent decades ushered in gate delay cut-off and rise of interconnection latency. Hence, interconnects have become a major performance bottleneck of high performance system-on-chips (SoC) and integrated circuits (IC). In addition, interconnectiosns have become more susceptible to noises in particular crosstalk. On the other hand, the advent of multi-core processors with ever increasing number of cores has highlighted the need for fast and reliable interconnections. One of the potential solutions to alleviate the interconnection delay problem is the three dimensional integration using through-silicon vias (TSV). Vertical integration of IC dies using TSVs offers high...
Production and Characterization of p-n Junction TiO2-NiO Nanocomposite in Order to Improve the Photocatalytic Efficiency
, M.Sc. Thesis Sharif University of Technology ; Sadrnezhaad, Khatiboleslam (Supervisor)
Abstract
Solar energy is one of the man's solutions to cope with problems involved in exhaustible fossil resources. In this regard, using photocatalysts is a practical and rational pproach.Nanotechnology facilitates using catalysts and photocatalysts with more productivity.TiO2 semiconductor is one of the most popular material in this field but its efficiency is low by several factors such as being inactive in visible light, recombination and the high cost of using noble metals. In this research, we tried to fix these limitations by creating a p-n junction TiO2 - NiO nanocomposite. The samples are made by three methods: impregnation, ultrasonic assisted modified impregnation with ammonium hydroxide...
Investigation on Effects of Nanoparticles Presence on Hydrate Formation Characterization During Drilling
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar (Supervisor) ; Zarenezhad, Bahman (Co-Advisor) ; Ramazani, Ahmad (Co-Advisor)
Abstract
In past two decades, the direction of oil and gas exploration has moved towards deep water drilling. The pressure and temperature in these zones are ideal for gas hydrate formation that can cause serious and sometimes uncontrollable issues during drilling operations. Gas hydrate formation while drilling can cause problems such as occurrence of kick and blowout, plug chock and kill line, and change in rheology of drilling mud. On the other hand, nowadays, nanotechnology has created an evolution in engineering sciences and because of the wide range of this science, drilling industry is affected like other industries. In the meantime, because of high yield, high stability and various methods of...
Analysis and Design of Nanoantenna Arrays
, M.Sc. Thesis Sharif University of Technology ; Akbari, Mahmood (Supervisor)
Abstract
If the size of the conventional telecommunication antennas -that are widely used in transmitting broadcasted radio and TV messages- is reduced by a nanometer size these antennas can be used at optical frequencies. Dimensions of these optical nanoantennas -that made of nanoparticles with highly permittivity- can be smaller than half of the wavelength. Based on this capability, optical nanoantennas have some important applications such as optical communication, photovoltaic devices, non-classical light, and optical sensing. After studying on optical nanoantennas and their features, in this project, we present distinctions between optical NAs and MW antennas and then investigate about different...
Analysis of Success Factors in Technological Cooperations in Nanotech Industry-a Multiple Case Study
, M.Sc. Thesis Sharif University of Technology ; Sheikhzadeh, Mehdi (Supervisor)
Abstract
Innovative small tech companies are required to often have cooperation with large companies in order to scale-up and commercialize their products. Such cooperation is referred as “Technological Cooperation” since it relies on development and commercialization of technology. In this research, as a multiple-case study in the arena of nanotechnology, five cases of technological cooperation are analyzed and key successful factors are identified. In this endeavor, 15 comprehensive interviews were conducted with both small tech companies and technology applicant companies, including experts of Nanotechnology Innovative Council (INIC) – playing the role of a mediator. Due to lack of a comprehensive...
The Size Effect of Coarse-Grained Modeling for Nonlinear Behavior of Nano-Structure Materials
, M.Sc. Thesis Sharif University of Technology ; Khoei, Amir Reza (Supervisor) ; Jahanshahi, Mohsen (Supervisor)
Abstract
The development of Nanotechnology increasingly has elevated the urgency for the expansion of modern numerical and computational methods that have evaluating systems with capability at this scale. In spite of being fully capable of evaluating nanostructures, the existing techniques, such as Molecular Dynamics Methods, lack the ability to simulate large systems of practical size and time scales. Thus, being able to create a large model of realistic simulation, which is confined by the computational expense of the running Molecular Dynamics methods at hand, Coarse-Graining technique has recently become a very effective and beneficial method which refers to the development of simplified models of...
Boltzmann Method for Investigating the Non-Linear Mechanical Behavior of Coarse- Grained Crystals with FCC Network, Exploiting the Effect of Dislocation
, M.Sc. Thesis Sharif University of Technology ; Khoei, Amir Reza (Supervisor) ; Jahanshahi, Mohsen (Supervisor)
Abstract
In these days world, the increasing growth of Nanotechnology has caused to invent and create new numerical and also computational methods which have more abilities and capabilities for evaluating systems in this scale. Although Some techniques, such as Molecular Dynamics Methods are capable of evaluating nanostructures, lack the ability to simulate large systems of practical size and time scales which is the most important index during the simulation. Therefore, in order to be able to produce an acceptable exact simulation of a large model, simulation of which is limited by the computational cost of the current molecular dynamics methods at hand, Coarse-Graining technique has recently become...
Single event multiple upset-tolerant SRAM cell designs for nano-scale CMOS technology
, Article Turkish Journal of Electrical Engineering and Computer Sciences ; Volume 25, Issue 2 , 2017 , Pages 1035-1047 ; 13000632 (ISSN) ; Asgari, B ; Tabandeh, M ; Fazeli, M ; Sharif University of Technology
Turkiye Klinikleri Journal of Medical Sciences
2017
Abstract
In this article, two soft error tolerant SRAM cells, the so-called RATF1 and RATF2, are proposed and evaluated. The proposed radiation hardened SRAM cells are capable of fully tolerating single event upsets (SEUs). Moreover, they show a high degree of robustness against single event multiple upsets (SEMUs). Over the previous SRAM cells, RATF1 and RATF2 offer lower area and power overhead. The Hspice simulation results through comparison with some prominent and state-of-the-art soft error tolerant SRAM cells show that our proposed robust SRAM cells have smaller area overhead (RAFT1 offers 58% smaller area than DICE), lower power delay product (RATF1 offers 231.33% and RATF2 offers 74.75%...
CFD aided procedure for optimizing electrical mobility spectrometer
, Article Defect and Diffusion Forum ; Volume 366 , 2016 , Pages 73-87 ; 10120386 (ISSN) ; Shaygani, A ; Sani, M ; Saidi, M. S ; Sharif University of Technology
Trans Tech Publications Ltd
Abstract
Aerosol measurement is used in a variety of fields such as nanotechnology, materials science, pollution monitoring, air quality measurements, combustion and engine exhaust analysis, inhalation toxicology, and medical studies. One of the most prevalent methods for aerosol measurement is to use electrical mobility. An electrical mobility spectrometer (EMS) is used to measure aerosol particles size distribution ranging from 10-1000 nanometers, under the influence of an electric field. The accuracy of this distribution is influenced by flow conditions, the geometry of the EMS, the electric field, and the number of electrode rings. In this work, a multi-channel EMS is studied using computational...
Mechanisms governing microstructural evolution during consolidation of nanoparticles
, Article Materials and Manufacturing Processes ; Volume 30, Issue 11 , 2015 , Pages 1397-1402 ; 10426914 (ISSN) ; Mahnama, M ; Naghdabadi, R ; Sharif University of Technology
Taylor and Francis Inc
2015
Abstract
In micron-scale, powder consolidation process is driven by diffusion phenomenon, while in nano-scale the higher surface energy of particles leads to some anomalous behaviors within the process. In order to investigate the nano-sintering occurrence, an atomistic approach is employed via molecular dynamics simulations. Within this approach, the effect of particle size and temperature is examined. The study of particle structure emphasizes on a transition on the governing mechanism of process depending on the material energy levels. The results show that in a specific particle size at low temperatures, the main sintering mechanism is the plastic deformation, while at elevated temperatures it...
Nanomechanical properties of MscL α helices: A steered molecular dynamics study
, Article Channels ; Volume 11, Issue 3 , 2017 , Pages 209-223 ; 19336950 (ISSN) ; Bavi, O ; Vossoughi, M ; Naghdabadi, R ; Hill, A. P ; Martinac, B ; Jamali, Y ; Sharif University of Technology
Taylor and Francis Inc
2017
Abstract
Gating of mechanosensitive (MS) channels is driven by a hierarchical cascade of movements and deformations of transmembrane helices in response to bilayer tension. Determining the intrinsic mechanical properties of the individual transmembrane helices is therefore central to understanding the intricacies of the gating mechanism of MS channels. We used a constant-force steered molecular dynamics (SMD) approach to perform unidirectional pulling tests on all the helices of MscL in M. tuberculosis and E. coli homologs. Using this method, we could overcome the issues encountered with the commonly used constant-velocity SMD simulations, such as low mechanical stability of the helix during...
Challenge in particle delivery to cells in a microfluidic device
, Article Drug Delivery and Translational Research ; Volume 8, Issue 3 , 2018 , Pages 830-842 ; 2190393X (ISSN) ; Saidi, M. S ; Kashaninejad, N ; Nguyen, N. T ; Sharif University of Technology
Springer Verlag
2018
Abstract
Micro and nanotechnology can potentially revolutionize drug delivery systems. Novel microfluidic systems have been employed for the cell culture applications and drug delivery by micro and nanocarriers. Cells in the microchannels are under static and dynamic flow perfusion of culture media that provides nutrition and removes waste from the cells. This exerts hydrostatic and hydrodynamic forces on the cells. These forces can considerably affect the functions of the living cells. In this paper, we simulated the flow of air, culture medium, and the particle transport and deposition in the microchannels under different angles of connection inlet. It was found that the shear stress induced by the...
A novel method for producing unequal sized droplets in micro- and nanofluidic channels
, Article European Physical Journal E ; Volume 38, Issue 9 , September , 2015 ; 12928941 (ISSN) ; Moosavi, A ; Kazemzadeh Hannani, S ; Sharif University of Technology
Springer New York LLC
2015
Abstract
Abstract: We propose a novel method for producing unequal sized droplets through breakup of droplets. This method does not have the disadvantages of the available methods and also reduces the dependence of the droplets volume ratio on the inlet velocity of the system by up to 26 percent. The employed method for investigating the proposed system relies on 3D numerical simulation using the VOF algorithm and the results have been obtained with various valve ratios for both the micro- and nanoscale. The results indicate that the droplet length during the breakup process increases linearly with time. The droplet length at the nanoscale is smaller than that at the micro scale. It has been shown...
Recent advances in the design and applications of amyloid-β peptide aggregation inhibitors for Alzheimer’s disease therapy
, Article Biophysical Reviews ; Volume 11, Issue 6 , 2019 , Pages 901-925 ; 18672450 (ISSN) ; Khazaei, S ; Behnammanesh, H ; Shamloo, A ; Erfani, M ; Beiki, D ; Bavi, O ; Sharif University of Technology
Springer
2019
Abstract
Alzheimer’s disease (AD) is an irreversible neurological disorder that progresses gradually and can cause severe cognitive and behavioral impairments. This disease is currently considered a social and economic incurable issue due to its complicated and multifactorial characteristics. Despite decades of extensive research, we still lack definitive AD diagnostic and effective therapeutic tools. Consequently, one of the most challenging subjects in modern medicine is the need for the development of new strategies for the treatment of AD. A large body of evidence indicates that amyloid-β (Aβ) peptide fibrillation plays a key role in the onset and progression of AD. Recent studies have reported...
A state-of-the-art review of the fabrication and characteristics of titanium and its alloys for biomedical applications
, Article Bio-Design and Manufacturing ; 2021 ; 20965524 (ISSN) ; Rezvani Ghomi, E ; Alipour, S ; Ramakrishna, S ; Liana Sukiman, N ; Sharif University of Technology
Springer
2021
Abstract
Abstract: Commercially pure titanium and titanium alloys have been among the most commonly used materials for biomedical applications since the 1950s. Due to the excellent mechanical tribological properties, corrosion resistance, biocompatibility, and antibacterial properties of titanium, it is getting much attention as a biomaterial for implants. Furthermore, titanium promotes osseointegration without any additional adhesives by physically bonding with the living bone at the implant site. These properties are crucial for producing high-strength metallic alloys for biomedical applications. Titanium alloys are manufactured into the three types of α, β, and α + β. The scientific and clinical...