Search for: nanotechnology
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    Group 6 transition metal dichalcogenide nanomaterials: synthesis, applications and future perspectives

    , Article Nanoscale Horizons ; Volume 3, Issue 2 , 2018 , Pages 90-204 ; 20556756 (ISSN) Samadi, M ; Sarikhani, N ; Zirak, M ; Zhang, H ; Zhang, H. L ; Zaker Moshfegh, A. R ; Sharif University of Technology
    Royal Society of Chemistry  2018
    Group 6 transition metal dichalcogenides (G6-TMDs), most notably MoS2, MoSe2, MoTe2, WS2 and WSe2, constitute an important class of materials with a layered crystal structure. Various types of G6-TMD nanomaterials, such as nanosheets, nanotubes and quantum dot nano-objects and flower-like nanostructures, have been synthesized. High thermodynamic stability under ambient conditions, even in atomically thin form, made nanosheets of these inorganic semiconductors a valuable asset in the existing library of two-dimensional (2D) materials, along with the well-known semimetallic graphene and insulating hexagonal boron nitride. G6-TMDs generally possess an appropriate bandgap (1-2 eV) which is... 

    Analytical model of the effect of tangent length between vertical curves on train derailments

    , Article Application of Nanotechnology in Pavements, Geological Disasters, and Foundation Settlement Control Technology ; 2014 , Pages 40-45 Molan, A. M ; Khodabakhshi, A ; Aman, J. J. C ; Sharif University of Technology
    Derailment is one of the most hazardous occurrences affecting the safety of railroad cars that must be prevented. The potential threat of derailment could be especially significant when length of tangent between vertical curves isn't long enough. Although the length of tangent between vertical curves could be relevant to railway safety, no research had been conducted to study its effect on derailment risk. The primary objective of this paper was to investigate the effect of tangent length between vertical curves on derailment. This study consisted of three major components: (1) review of 1999-2008 derailment reports in Iran, (2) a regression analysis, and (3) recommendation model for... 

    Transistor Based on Graphane

    , M.Sc. Thesis Sharif University of Technology Babaee Touski, Shoeib (Author) ; Khorasani, Sina (Supervisor)
    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... 

    Toward green revolution in concrete industry: The role of nanotechnology (A review)

    , Article Australian Journal of Basic and Applied Sciences ; Volume 5, Issue 12 , 2011 , Pages 2768-2782 ; 19918178 (ISSN) Hosseini, P ; Mohamad, M. I ; Nekooie, M. A ; Taherkhani, R ; Booshehrian, A ; Sharif University of Technology
    Nowadays, the development of nanotechnology is faster than before due to its interdisciplinary nature. Other branches of engineering have started employing this technology in the process of their development; one example would be concrete science and technology. Nearly a decade has passed since the first application of nano-particles in a matrix of concrete products. During this time period, two directions have formed in the process of researchers' investigations. The first route is the precise monitoring of the microstructure and macrostructure of concrete products with the help of nanotechnology tools and methods. The second route is the development of concrete products with... 

    Investigation on Coupling of Molecular Dynamics Method and Temperature Related Cauchy Born Methods

    , M.Sc. Thesis Sharif University of Technology Farsadnia, Saeed (Author) ; Kazemi, Mohammad Taghi (Supervisor)
    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... 

    Planar molecular dynamics simulation of Au clusters in pushing process

    , Article International Journal of Nanomanufacturing ; Vol.5, No.3/4 , 2010 , pp.288-296 Mahboobi, S. H ; Meghdari, A. (Ali) ; Jalili, N. (Nader) ; Amiri, F. (Farshid) ; Sharif University of Technology
    Based on the fact that the manipulation of fine nanoclusters calls for more precise modelling, the aim of this paper is to conduct an atomistic investigation for interaction analysis of particle-substrate system for pushing and positioning purposes. In the present research, 2D molecular dynamics simulations have been used to investigate such behaviours. Performing the planar simulations can provide a fairly acceptable qualitative tool for our purpose while the computation time is reduced extremely in comparison to 3D simulations. To perform this study, Nose-Hoover dynamics and Sutton-Chen interatomic potential will be used to investigate the behaviour of the aforementioned system. Pushing of... 

    The study of growth and coagulation of titania nanoparticles by chemical vapor synthesis

    , Article Journal of Nuclear Science and Technology ; No.53 , 2010 , pp. 20-29 Rahiminezhad-Soltani, M ; Saberyan, K ; Shahri, F ; Simchi, A. (Abdolreza) ; Sharif Univesity of Technology
    Chemical Vapor Synthesis route was used for synthesis of titanium dioxide (TiO2) nanoparticles in hot-walled reactor at 800degreeC using TiCl4 as precursor. The effect of processing parameters e.g., temperature and amount of precursor on phase structure, size, purity, coagulation and agglomeration of nanoparticles were investigated in this respect. Also, the H2O effects on the size, crystallinity, phase transformation and purity of nanoparticles were studied. Comprehensive experimental observations were confirmed by transmission electron microscopy, X-ray diffraction analysis and thermal gravimetric-differential thermal analysis results. The obtained results showed that by increasing the... 

    Impedimetic biosensor for the DNA of the human papilloma virus based on the use of gold nanosheets

    , Article Microchimica Acta ; Volume 184, Issue 6 , 2017 , Pages 1729-1737 ; 00263672 (ISSN) Karimizefreh, A ; Aghakhani Mahyari, F ; VaezJalali, M ; Mohammadpour, R ; Sasanpour, P ; Sharif University of Technology
    The authors describe an impedimetric method for the quantitation of the DNA of the human papilloma virus (HPV) type 16. A glassy carbon electrode (GCE) was modified with gold nanosheets and is shown to be superior to a common gold disk electrode. A single-stranded 25mer oligonucleotide (ssDNA) acting as the probe DNA was immobilized via its thiolated 5′ end on both electrodes. After hybridization with target (analyte) DNA, electrochemical impedance spectra were acquired in the presence of hexacyanoferrate as a redox marker. The sensor can distinguish between complementary, non-complementary and single base pair mismatches of HPV ssDNA. At a 1 mM hexacyanoferrate concentration, the biosensors... 

    Production and Characterization of p-n Junction TiO2-NiO Nanocomposite in Order to Improve the Photocatalytic Efficiency

    , M.Sc. Thesis Sharif University of Technology Bakhtiarnia, Siavash (Author) ; Sadrnezhaad, Khatiboleslam (Supervisor)
    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... 

    Application of electrostatically actuated carbon nanotubes in nanofluidic and bio-nanofluidic sensors and actuators

    , Article Measurement: Journal of the International Measurement Confederation ; Volume 73 , September , 2015 , Pages 127-136 ; 02632241 (ISSN) Seyyed Fakhrabadi, M. M ; Rastgoo, A ; Ahmadian, M. T ; Sharif University of Technology
    Elsevier  2015
    The paper investigates the effects of fluid flow on the static and dynamic behaviors of electrostatically actuated carbon nanotubes using nonlocal elasticity theory. The influences of various parameters of fluid flow including fluid viscosity, velocity, mass and temperature on the mechanical behaviors of the carbon nanotubes under static and step DC voltages are studied using this theory. The results computed from the nonlocal elasticity theory are compared with those estimated using the classical elasticity theorem and the outcomes demonstrate the applicability of the electrostatically actuated carbon nanotubes as nano sensors and nano actuators in nanofluidic systems. The nanosystem can be... 

    The analysis of critical factors of success (failure) for Iran nanotechnology research & development via fuzzy map approach

    , Article IEOM 2015 - 5th International Conference on Industrial Engineering and Operations Management, Proceeding, 3 March 2015 through 5 March 2015 ; 2015 ; 9781479960651 (ISBN) Yassaei, S ; Ghassemi, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Experiment is a procedure for verifying or establishing the validity of a hypothesis and then measuring or evaluating its outcomes. Due to the inherent uncertainties or ambiguities of its outcomes, a further treatment is needed for producing identical results. Fuzzy map is an approach for removing the uncertainties of the outcomes. In this manuscript, the procedure employed for conducting research and development in the field of nontechnology, in a developing country, is considered and the factors governing its success and its failures are analyzed. To accomplish this task, a thorough literature review was performed and the related critical factors were identified. Then an extensive survey... 

    Electrochemical sensing based on carbon nanoparticles: A review

    , Article Sensors and Actuators, B: Chemical ; Volume 293 , 2019 , Pages 183-209 ; 09254005 (ISSN) Asadian, E ; Ghalkhani, M ; Shahrokhian, S ; Sharif University of Technology
    Elsevier B.V  2019
    The emergence of nanoscience and nanotechnology has opened up new horizons to researchers. In this regard, carbon nanomaterials are considered as the cornerstone of numerous investigations. Among various carbon nanostructures, “Carbon nanoparticles (CNPs)” have attracted a great deal of attention during the past few years due to their unique properties such as high surface area, non-toxicity, biocompatibility as well as simple and low-cost synthetic procedures via environmentally friendly routes. Thanks to these properties along with their interesting optical behavior, CNPs have found diverse applications in the fields of bioimaging, nanomedicine, photo/electro-catalysis, and bio/chemical... 

    Investigation on Effects of Nanoparticles Presence on Hydrate Formation Characterization During Drilling

    , M.Sc. Thesis Sharif University of Technology Jalilolghadr Ardabili, Raouf (Author) ; Mohammadi, Ali Asghar (Supervisor) ; Zarenezhad, Bahman (Co-Advisor) ; Ramazani, Ahmad (Co-Advisor)
    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... 

    Anomaly in current distribution of multiwall carbon nanotube bundles at high frequencies

    , Article 14th IEEE International Conference on Nanotechnology, IEEE-NANO 2014 ; 2014 , pp. 702-705 ; ISBN: 9781479956227 Farahani, E. K ; Sarvari, R ; Sharif University of Technology
    In this paper, for the first time, current distribution inside multiwall carbon nanotube (MWCNT) bundles is studied in the high frequency range in which resistance becomes saturated. It is shown that current distribution of MWCNT bundles in this range is not strictly decreasing vs. distance from surface as in Cu wires  

    Design of multilevel interconnect network of an ASIC macrocell for 7.5nm technology node using carbon based interconnects

    , Article 2014 IEEE International Interconnect Technology Conference / Advanced Metallization Conference, IITC/AMC 2014 ; May , 2014 , p. 163-166 Farahani, E. K ; Sarvari, R ; Sharif University of Technology
    Multilevel interconnect network of a macrocell for 7.5 nm technology node is designed with carbon based interconnects (CBI) and Cu. Results are compared. Constrains of using CBI is discussed. It is shown that by using CBI power dissipation associated with wires could decrease by 32%. To use GNRs for more than one metal pair, reverse wire pitch idea is proposed that prevents undesirable increase in the number of metal layers  

    The Comparative Study of Nanotechnology Research and Development in The World Selected Countries

    , M.Sc. Thesis Sharif University of Technology Yassaei, Shahla (Author) ; Ghasemi, Farhad (Supervisor)
    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 Samimi, Armin (Author) ; Roosta Azad, Reza (Supervisor) ; Moosavi, Abbas (Supervisor)
    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... 

    Feasibility Study of Application of Developing New Techniques for Fuel Cell Vehicle by Focusing on Nanotechnology

    , M.Sc. Thesis Sharif University of Technology Salehi, Mohammad Bagher (Author) ; Mostafavi, Mostafa (Supervisor)
    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... 

    Analysis of Success Factors in Technological Cooperations in Nanotech Industry-a Multiple Case Study

    , M.Sc. Thesis Sharif University of Technology Malekifar, Mehdi (Author) ; Sheikhzadeh, Mehdi (Supervisor)
    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... 

    Suppression of dynamic pull-in instability in electrostatically actuated strain gradient beams

    , Article 2014 2nd RSI/ISM International Conference on Robotics and Mechatronics, ICRoM 2014 ; 2014 , pp. 155-160 ; ISBN: 9781479967438 Edalatzadeh, M. S ; Vatankhah, R ; Alasty, A ; Sharif University of Technology
    In this paper, vibration suppression of micro-or nano-scale beams subjected to nonlinear distributed electrostatic force is studied. For the sake of precision, we use the beam model derived from strain gradient elasticity theory aimed at prediction of size effect. In addition, the electrostatic force is considered with first order fringing field correction. The continuous model of the strain gradient beam is truncated by using Kantorovich method as a semi-analytical finite element method. A boundary control feedback law is proposed to suppress forced vibrations of the beam. Both measurements and actuations are taken place in the boundary to avoid spillover instabilities. Simulation results...