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    Pyrolytic carbon coating for cytocompatibility of titanium oxide nanoparticles: a promising candidate for medical applications [electronic resource]

    , Article Nanotechnology ; February 2012, Vol. 23, No. 4, PP. 045102 Behzadi, S. (Shahed) ; Imani, Mohammad ; Yousefi, Mohammad ; Galinetto, Pietro ; Simchi, Abdolreza ; Amiri, Houshang ; Stroeve, Pieter ; Mahmoudi, Morteza ; Sharif University of Technology
    Nanoparticles for biomedical use must be cytocompatible with the biological environment that they are exposed to. Current research has focused on the surface functionalization of nanoparticles by using proteins, polymers, thiols and other organic compounds. Here we show that inorganic nanoparticles such as titanium oxide can be coated by pyrolytic carbon (PyC) and that the coating has cytocompatible properties. Pyrolization and condensation of methane formed a thin layer of pyrolytic carbon on the titanium oxide core. The formation of the PyC shell retards coalescence and sintering of the ceramic phase. Our MTT assay shows that the PyC-coated particles are cytocompatible at employed doses  

    Fabrication of gas ionization sensor based on titanium oxide nanotube arrays

    , Article Applied Physics A ; Volume 115, Issue 4 , June , 2014 , pp 1387-1393 ; 1432-0630 Nikfarjam, A. (Alireza) ; Mohammadpour, R. (Raheleh) ; Iraji Zad, A. (Azam) ; Sharif University of Technology
    Gas sensors have been fabricated based on field ionization from titanium oxide nanotubes grown on titanium foil. Ordered nanaotube arrays of titanium oxides were grown by the anodization method. We measured breakdown voltages and discharge currents of the device for various gases. Our gas ionization sensors (GIS) presented good sensitivity, selectivity, and short response time. The GISs based on TiO2 nanotube arrays showed lower breakdown voltage, higher discharge current, and good selectivity. An excellent response observed for Ar compared to other gases. Besides, by introducing 2 % CO and 4 % H2 to N2 flow gas, the amount of breakdown voltage shifts about 20 and 70 volts to the lower... 

    Omega polynomial in titanium oxide nanotubes

    , Article Studia Universitatis Babes-Bolyai Chemia ; Issue 4 , 2010 , Pages 201-210 ; 12247154 (ISSN) Ghorbani, M ; Hosseinzadeh, M. A ; Diudea, M. V ; Sharif University of Technology
    A new counting polynomial, called Omega Ω(G,x), was recently proposed by Diudea. It is defined on the ground of "opposite edge strips" ops. Two related polynomials: Sadhana Sd(G,x) and Theta Θ(G,x) polynomials can also be calculated by ops counting. Close formulas for calculating these three polynomials in infinite nano-structures resulted by embedding the titanium dioxide pattern in plane, cylinder and torus are derived. For the design of titanium dioxide pattern, a procedure based on a sequence of map operations is proposed  

    Fabrication of one Dimensional Nano-Structured of Titanium Dioxide and their Application in Dye Sensitized Solar Cells

    , M.Sc. Thesis Sharif University of Technology Rahimi, Sanam (Author) ; Iraji Zad, Azam (Supervisor)
    In this research we focus on study and fabrication of titanium dioxide nanofibers and their application in preparation of dye sensitized solar cell’s photo anode in order to improve optical and electrical properties. Titanium dioxide nanofibers was prepared by electroespinning method. To investigate the effect of nanofiber diameter on optical and electrical properties of photo anode, three different diameter of titanium dioxide nanofibers with diameters of 100-200 nm, 200-300 nm and 500-600 nm was prepared by varying the type or amount of polymer in the electrospinning solution and fixing other conditions of electrospinning process. By use of these structures, paste of pure fibers in form of... 

    Fabrication of a Sensor, Based on TiO2 Nanotubes Modified with Metal Nanoparticles and Carbon and its Application for Detection of Dopamine in Presence of Uric Acid and Ascorbic Acid

    , Ph.D. Dissertation Sharif University of Technology Mahshid, Sara (Author) ; Askari, Masoud (Supervisor) ; Dolati, Abolghasem (Supervisor)
    The present work describes sensing application of modified TiO2 nanotubes towards detection of dopamine. The TiO2 nanotubes electrode was prepared using anodizing method at different conditions, among which NaF/ NaHSO4 solution and voltage of 15 V was chosen as the optimum condition. In order to improve the performance, surface modification with metal nanoparticles (Pd, Pt and Au) and carbon is required using “pulse electrodeposition” and “decomposition of polyethylene glycol at 600 °C” respectively. Carbon was deposited by decomposition of polyethylene glycol in a tube furnace to improve the conductivity. In this regard two type of electrodes were proposed: Pd-Pt-Au-TiO2 and C-Ni(Pt)-TiO2.... 

    Synthesis of Titanium Dioxide-graphene Nanocomposite: Characterization and Photocatalyst Applications

    , M.Sc. Thesis Sharif University of Technology Malakooti Tehrani, Shahin (Author) ; Mohammadi, Mohammad Reza (Supervisor)
    TiO2 and TiO2-Graphene have been synthesized by hydrothermal method. Their physical, chemical and morphological properties have been investigated using XPS, XRD, FTIR, TEM, EDX, UV-Vis and AFM analyses. Moreover, photocatalytic efficiency of prepared materials has been examined using degradation of methylene blue. AFM image exhibited that monolayer GO with thickness of 10 nm was synthesized using modified Hummer’s method. FTIR analysis represented main characteristic peak of oxygen bond on the surface of GO, whereas for TiO2-Graphene most of oxygen functionalities on the surface were removed partially or completely. Photocatalytic degradation of MB proved this extension of light absorption.... 

    Lithium Extraction with TiO2 Nanotube Synthesized by Anodizing Method

    , M.Sc. Thesis Sharif University of Technology Taghvaei, Nastaran (Author) ; Askari, Masoud (Supervisor)
    Due to the technology advancement and the large-scale application of lithium-ion batteries in recent years, the market demand for lithium is growing rapidly and the availability of land lithium resources is decreasing significantly. As such, the focus of lithium extraction technologies has shifted to water lithium resources involving salt-lake brines and sea water. The ion exchange process is a promising method for lithium extraction from brine and seawater having low concentrations of this element. Among various aqueous recovery technologies, the lithium ion-sieve (LIS) technology is considered the most promising one. This is because LISs are excellent adsorbents with high lithium uptake... 

    Enhancement of Water Splitting Efficiency of TiO2 Nanotube Arrays by Nanostructured Cobalt Oxide Electrocatalyst

    , M.Sc. Thesis Sharif University of Technology Qarechalloo, Shervin (Author) ; Naseri, Naimeh (Supervisor)
    The 21st century is facing two major obstacles on the way of accessing clean and renewable energies: first, the rapidly increasing need to the energy resources; and second, the limitations - as well as side-effects - of the conventional fossil fuels. Meanwhile, the production of the solar hydrogen, through water splitting, has been proposed as a promising solution to find a clean and effective source of energy. This process occurs in photo-electro-chemical systems with the activation energy that lies within the range of visible light. One approach that herewith comes to mind, is to start the process by utilizing semiconductors to absorb the sunlight. In order to overcome the overpotential... 

    Production of Al-TiO2 composite layer by friction stirs processing

    , M.Sc. Thesis Sharif University of Technology Nami, Hamid (Author) ; Kokabi, Amir Hossein (Supervisor) ; Maddah Hosseini (Co-Advisor)
    In this study, Al-TiO2 composites layer were produced on Al 1100 substrate using friction stir processing technique. The variation of process parameters such as tool rotational and substrate advancing speed as well as number of FSP passes were adjusted to achieve quite uniform dispersion of Nano-particles in the Al matrix of the fabricated surface layer. Microstructural observations were carried out using optical and scanning electron microscopes. By increasing the FSP passes, uniform distribution of TiO2 particles in the matrix improved. Surface composition layer exhibited a micro-hardness value of 49 HV which was around twice of the as-received substrate. In addition wear resistance of... 

    Investigation of Vanadium Dopant and SiO2 Prelayer on the Self-Cleaning Property of TiO2 Coatings by Sol-Gel Dip Coating Method

    , M.Sc. Thesis Sharif University of Technology Namkhah, Yalda (Author) ; Faghihi Sani, Mohammad Ali (Supervisor)
    Because of limitation of titania coating that can act as self-cleaning surface under UV light irradiation, introduction of transition metal ions into titania lattice can decrease band gap energy of titania in order to activate the coating under visible light irradiation. In this research, by using vanadium element and silica prelayer, a titania coating was deposited on the soda-lime glass substarte to produce self-cleaning surface. The scope of coating was to increase the photocatalytic activity and hydrophilicity of vanadium doped titania coating on the soda-lime glass and silica coated glass by sol-gel dip coating method. XRD and FTIR analysis were done on the powders with different... 

    Synthesis of Anti-reflection and Self-cleaning Coating on Glass Substrate Using Sol-gel Method

    , M.Sc. Thesis Sharif University of Technology Sharifi Rad, Alireza (Author) ; Afshar, Abdollah (Supervisor)
    Using of solar spectrum because of its potential for producing green energy is the topic of interest in Current decade. The goal of current research is increment of efficiency by using of a single layer and double layer semiconductor TiO2 – ZnO coating that has been synthesized by sol-gel process, which have anti-reflation and self-cleaning properties that in short time and long time for durability of solar systems can be useful. In first step of this research the single layer TiO2 (by 85nm thickness, measured by FE-SEM) and ZnO (by 65nm thickness) coating with different concentrations of pore forming agents ( plironic f127 for TiO2 and CTAB for ZnO) in coating sol examined and observed... 

    Synthesis of ZnO and ZnO-TiO2 Nanocoatings by Sol-Gel Methode and Study in Their Antibacterial and Photocatalyst Properties

    , M.Sc. Thesis Sharif University of Technology Nournia, Shayan (Author) ; Dolati, Abolghasem (Supervisor)
    The goal of this study is synthesis of nanocoating on basis of ZnO by Sol-Gel method and evaluation of their antibacterial and photocatalyst properties changes by different values of TiO2. For this purpose in both method of synthesis contents of TiO2 hase been changed from 0-25 molar percent. Dip coat method has been used for coating from sol with 1.4 mm/s withdrawal speed and 2 minute immersion time. After each step of coating samples has been dried at 150oC for 10 minute and for increasing thickness this process has been repeated 4 times. In first method zinc acetate dihydrate in 0.1 M final concentration and titanium tetraisopropoxide are sol precursors at in situ way of synthesis. In... 

    Microemulsion Synthesize of Fe3O4/TiO2 Core-Shell Nanoparticles

    , M.Sc. Thesis Sharif University of Technology Sonbolestan, Hosein (Author) ; Madaah Hoseini, Hamid Reza (Supervisor)
    In this study magnetite nanoparticles were synthesized by microemulsion and were coated with TiO2 by a precipitation technique. The synthesize process were done under fixed molar ratio of various constituents of microemulsion and molar ratio of water to oil. Results of X-ray diffraction spectroscopy (XRD) showed that the uncoated nanoparticles were consisted of magnetite as the major phase and no other detectable phases such as pure iron or hematite were found. Field emission scanning electron microscopy (FE-SEM) results showed that the synthesized nanoparticles small size and narrow particle size distribution. For TiO2 coating process the effect of TBOT concentration, water concentration,... 

    Study on Nucleation and Growth of Titanium Dioxide Nano Particles via Gel-Sol Method

    , M.Sc. Thesis Sharif University of Technology Shahini, Sharif (Author) ; Askari, Masoud (Supervisor)
    Nanotechnology is an efficient method suitable for fabrication and production of minimal single dimensional nanometric structures. Such materials and systems can be logically designed that lead to new and optimized biological, chemical and physical properties and characteristics due to their size. Nucleation and growth –appearance of a new phase out of an old phase – is a ubiquitous phenomenon in nature. Fundamental understanding of nanoparticles nucleation and growth mechanism allows more control on form, size and composition and allows tuning of the above said properties easily with use of different reactive conditions as a result of this ability . Nanoparticles of titania are one of... 

    Nano Structure TiO2 Films by Hybrid PEO-Hydrothermal Method for Dye Sensitised Solar Cell Applications

    , M.Sc. Thesis Sharif University of Technology Shakoorian, Sheida (Author) ; Faghihi-Sani, Mohammad Ali (Supervisor) ; Mohammadpour, R (Co-Advisor)
    This thesis demonstrate a new hybrid Plasma Electrolytic Oxidation (PEO)-Hydrothermal method to produce a nano-structured TiO2 layer over a titanium substrate. Microstructural characterization was carried out by using a FE-SEM to explore nano scale structural changes due to hydrothermal treatment. More over EDS was used to analyse elements of the coating. The FE-SEM images confirmed formation of a 3D network consisting “nano flakes+nano fibers”after 6 or 12 hours and a ”sea urchin like nanostructure+nano fibers” after 24 hour. To improve the performance of nano-structured photoelectrodes, different electrolytes were studied to achieve maximum amount of anatase phase. the best results was... 

    Photoactive TiO2–SiO2 Thin Films on 316L Stainless Steel for Self-Cleaning Application, Tribological Properties and Corrosion Protection

    , Ph.D. Dissertation Sharif University of Technology Shayegh Boroujeny, Behrooz (Author) ; Afshar, Abdollah (Supervisor) ; Dolati, Abolghasem (Supervisor)
    In this study, TiO2-SiO2 nanocomposite films with different amount of SiO2 were prepared by sol-gel process and were coated onto stainless steel 316L. The effect of addition of various amounts of SiO2 in the precursor solution on the structure, morphology, photocatalysis, photo-generated hydrophilicity, self-cleaning property and mechanical properties of TiO2 thin films and corrosion behavior of AISI 316L stainless steel substrate, was investigated. For this purpose, X-ray diffraction, Fourier transform infrared spectroscopy, water contact angle measurements, UV spectroscopy, field-emission scanning electron microscopy, atomic force microscopy, depth-sensing indentation technique supporting... 

    Synthesis of Doped Titania Nanotube Arrays by Anodizing of Titanium and Surveying of their band Gap

    , M.Sc. Thesis Sharif University of Technology Meftahi, Mohammad (Author) ; Ghorbani, Mohammad (Supervisor)
    In recent decade, photocatalystic properties of titania nanotube and its mechanisms has been considered greatly in many researches. One of the major ways to increase photocatalystic properties and extending the usage of TNTs is doping them with various elements and modifying their band structure. In present research doped TNTs were prepared by doping of Molybdenum, Nitrogen, and Carbon elements by anodizing method in about of 35 degrees of centigrade and constant voltage of 20V on the surface of titanium sheet. Structural and photocatalystic properties of as-prepared TNTs were studied using field emission scanning electron microscope (FESEM), x-ray diffraction (XRD), energy dispersive... 

    Enhanced Photocatalytic Activity of Nano-scaled TiO2 Co-doped with N and Ag by Sol-gel Method

    , M.Sc. Thesis Sharif University of Technology Azimi, Zahra (Author) ; Dolati, Abolghasem (Supervisor)
    Transparent coatings with self-cleaning property in visible light spectrum, UV radiation resistance and antimicrobial are highly desirable. Titanium dioxide (TiO2) is used in this research has been widely studied as an efficient photocatalyst by researchers. In this research enhanced visible-light photocatalytic activity is gained with N and Ag co-doped titania. All samples were annealed at 450℃. Finally AgI was loaded TiO2 coating and the results were investigated. Peaks of XRD pattern wereattributed to different diffraction planes of anatase TiO2. Morphology of coatings were analyzed with using FE-SEM. Nano granis size of TiO2 and AgI loaded TiO2 were observed in FE-SEMimages. Nitrogen... 

    The Effect of Porosity on Photocatalytic Properties of TiO2 Nanocoating Fabricated By Sol-Gel

    , M.Sc. Thesis Sharif University of Technology Mehmandoust, Ehsan (Author) ; Ghorbani, Mohammad (Supervisor)
    This thesis is concerned with the synthesis and characterization of high porous Ti based on thin films and the effect of polymer agents on their photocatalytic properties. Ti films can demonstrate different properties like self -cleaning and treatment of broad range of aqueous pollutants when it is exposed to light of wavelength less than 400 nm. This is due to photocatalytic reaction occurring on film surface which results in film superhydrophilicity and the active oxygen species production. This active sites and radicals will cause oxidize organic pollutants and microbe adherent to the material surface.
    In this study Ti thin films have been prepared by the sol-gel method from... 

    Nanostructural study of NiTi–TiO2–C core–shell nanoparticles generated by spark discharge method

    , Article Applied Physics A: Materials Science and Processing ; Volume 124, Issue 9 , 2018 ; 09478396 (ISSN) Arzi, M ; Sabzehparvar, M ; Sadrnezhaad, S. K ; Amin, M. H ; Sharif University of Technology
    Springer Verlag  2018
    Abstract: Nickel–titanium (NiTi) nanoparticles are ultrafine smart materials manifesting shape memory effect at very small scales. We have produced NiTi nanoparticles surrounded by an amorphous carbon shell using an innovative spark discharge system. The resulting nanoparticles were studied using various characterization methods to systematically study their size, morphology, size distribution, composition, structure, and thermal behavior. Field-emission scanning electron microscopy and dynamic light-scattering results indicated that the average size of the produced nanoparticles was about 13 nm. High-resolution transmission electron microscopy, energy-dispersive spectroscopy (EDS), and...