Search for: titanium
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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  

    The change in the chemical composition and toughness of API 5L-X70 welds by addition of titanium

    , Article International Journal of Modern Physics B ; Volume 23, Issue 6-7 , 2009 , Pages 1209-1216 ; 02179792 (ISSN) Beidokhti, B ; Koukabi, A. H ; Dolati, A ; He, P ; Sharif University of Technology
    The objective of this work was to study the influence of titanium variations on the API 5L-X70 steel weld metal properties. The relationship between microstructure and toughness of the weld deposit was studied by means of full metallographic, longitudinal tensile and Charpy-V notch tests on the specimens cut transversely to the weld beads. The best combination of microstructure and impact properties was obtained in the range of 0.02-0.05% titanium. By further increasing of titanium content, the microstructure was changed from a mixture of acicular ferrite, grain-boundary ferrite, Widmanstätten ferrite to a mixture of acicular ferrite, grain-boundary ferrite, bainite and ferrite with M/A... 

    Evaluation of electrical breakdown of anodic films on titanium in phosphate-base solutions

    , Article Surface and Coatings Technology ; Volume 186, Issue 3 , 2004 , Pages 398-404 ; 02578972 (ISSN) Afshar, A ; Vaezi, M. R ; Sharif University of Technology
    Titanium is a highly reactive metal, so that whenever it is exposed to air or other environments containing available oxygen, a thin layer of oxide is formed on the surface. This layer increases the corrosion resistance of titanium. The formation of the oxide film can be electrochemically performed by anodizing. In this research, anodizing of titanium was performed in phosphate-base solutions such as H3PO4, NaH2PO 4·2H2O and Na2HPO4 at 9.75 mA/cm2 and 35 °C under galvanostatic conditions. The potential-time curves in the above mentioned solutions show that the anodic films formed on Ti are compact and their thickness depends on the solution type and concentration. The SEM and XRD studies... 

    Anodizing of titanium in NaOH solution and its corrosion resistance in PBS physiologic solution

    , Article Scientia Iranica ; Volume 10, Issue 3 , 2003 , Pages 361-366 ; 10263098 (ISSN) Afshar, A ; Vaezi, M. R ; Sharif University of Technology
    Sharif University of Technology  2003
    Titanium is a highly reactive metal with an inclination to compose with oxygen. In order to increase its corrosion resistance and application, therefore, a thin layer of titanium oxide is produced on the surface by chemical and electrochemical methods. In the present research, titanium has been anodized in 20 M of NaOH solution under potentiostatic conditions at constant voltages of 25 and 35 V. The microstructure of the anodic layers has been studied by the use of a Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD). The results indicated that the structure of the anodic layers is amorphous with low porosity and that thickness increases with an increase in anodizing voltage. The... 

    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... 

    Synthesis of TiO2 nano powder by the sol-gel method and its use as a photocatalyst

    , Article Journal of the Iranian Chemical Society ; Volume 7, Issue SUPPL. 1 , 2010 , Pages S154-S160 ; 1735207X (ISSN) Karami, A ; Sharif University of Technology
    In this work the titanium dioxide powder was prepared by the optimized and simple Sol-Gel method and then characterized. The gelling pH was set to values of 3 (TiO2-A), 7 (TiO2-N) and 9 (TiO2-B) to observe the effect on the properties of the material. In these three cases nanoparticulated materials were obtained with particle sizes between 10nm and 20nm. The larger surface areas were obtained at pH 3, which is several times larger than the others. Furthermore, with the gelling condition pH 3, it was possible to synthesize pure anatase phase titania. Some preliminary results on the test of the photocatalytic activity of the synthesized materials in the reduction of nitric oxide are presented.... 

    Preparation and Characterization of Ternary Mixed Oxide Containing IrO2,RuO2,TiO2 on Platinum Coated Titanium Anode

    , M.Sc. Thesis Sharif University of Technology Ali Asghari, Sepideh (Author) ; Ghorbani, Mohammad (Supervisor) ; Davami, Parviz (Supervisor)
    Ruthenium based-oxide coatings on Titanium anodes are widely used as DSA (Dimensionally Stable Anode) for chlorine and chlorate production. Coatings consisting of composition of highly conductive oxide of noble metals (Ru, Ir and Pt) make them as long lasting anodes in chlor-alkali technology.In this work, a newly anode by a ternary coating of IrO2, RuO2, and TiO2 on the Pt-coated Ti was developed through thermal decomposition of iridium and titanium and ruthenium inorganic salts dissolved in n-pentane. The effect of deposition parameters such as current density, time, different condition of baking, heating, mole ratio and pulling up the samples was investigated to find out reasonable... 

    Highly efficient hydroxyapatite/TiO2 composites covered by silver halides as E. coli disinfectant under visible light and dark media

    , Article Photochemical and Photobiological Sciences ; Volume 12, Issue 10 , October , 2013 , Pages 1787-1794 Azimzadehirani, M ; Elahifard, M ; Haghighi, S ; Gholami, M. R. (Mohammad Reza) ; Sharif University of Technology
    TiO2-based photocatalysts are seen as the most common agents for the photodegradation of bacteria. In this study, AgCl/TiO2, hydroxyapatite(Hp)/AgCl/TiO2, AgI/TiO2, and Hp/AgI/TiO2 were prepared by the deposition-precipitation method on P25 TiO2 nanoparticles and were characterized by XRD, SEM, FT-IR, EDX and BET methods. The prepared composites showed high efficiency for the inactivation of Escherichia coli (E. coli) bacteria under visible light and in dark media with different catalyst amounts of 12 and 24 mg, respectively. In less than 30 min, AgI/TiO2, prepared by the combination of cationic surfactant and PVPI2, disinfected 1 × 10(7) colony-forming units of E. coli completely. However,... 

    Comparison of the corrosion resistance of alkaline- and acid-anodized titanium

    , Article Materials Performance ; Volume 54, Issue 1 , 2015 , Pages 51-55 ; 00941492 (ISSN) Karambakhsh, A ; Ghahramani, S ; Afshar, A ; Malekinejad, P ; Sharif University of Technology
    National Assoc. of Corrosion Engineers International  2015
    The process of self-color anodizing of titanium is done in acidic and alkaline solutions, and anodic films of different colors are formed. Results of this work show that the corrosion rate of titanium decreased after the application of an anodizing layer  

    Evaluation of the photo-catalytic degradation of pyrene using fe-doped tio2 in presence of UV

    , Article Desalination and Water Treatment ; Volume 169 , 2019 , Pages 232-240 ; 19443994 (ISSN) Khodadadi Saloot, M ; Borghei, S. M ; Haji Seyed Mohammad Shirazi, R ; Sharif University of Technology
    Desalination Publications  2019
    The oil-based compounds are widely used in modern human life, and the accidental release or leakage of these compounds is led to water and soil pollution and creates many problems for the environment. The purpose of this study was to determine the efficiency of photo-catalytic degradation of pyrene using Fe-doped TiO2 in the presence of UV. This experimental study was carried out at laboratory scale in a 2 L pilot reactor. The nanoparticle was synthesized by the sol-gel method. Pyrene degradation was investigated under different conditions of pH, reaction time, nanoparticle concentration and pollutant concentration. For the statistical analysis, SPSS V.16 software and one-way analysis of... 

    Investigation of the Antibacterial Property of TiO2/Ag Nanotubes

    , M.Sc. Thesis Sharif University of Technology Esfandiari, Naeemeh (Author) ; Simchi, Abdolreza (Supervisor) ; Bagheri, Reza (Supervisor)
    This study was performed to synthesize Ag-doped TiO2 nanotubes and investigate the antibacterial property of the nanostructure. In the first step, self-organized TiO2 nanotubes were fabricated through anodizing in an electrolyte containing 0٫3 Wt% NH4F, 0٫2٪V DI water and ethylene glycol. Anodizing was performed in 30 and 60V for 2hrs in order to have different nanotube diameters. In the second step, photoreduction process was done on the way to dope Ag nanoparticles on the nanotubes. Herein, AgNO3 solution concentration, time period of TiO2 nanotubes soaking in the solution, time period of UV irradiation and ethanol solution concentration were taken as factors to achieve Ag nanoparticles in... 

    Horseradish peroxidase immobilization on amine functionalized carbon nanotubes: direct electrochemistry and bioelectrocatalysis

    , Article Progress in Reaction Kinetics and Mechanism ; Volume 37, Number 2 , 2012 , pp. 161-172 Tasviri, M. (Mahboubeh) ; Ghourchian, H. (Hedayatollah) ; Gholami, M. R. (Mohammad Reza) ; Rafieepour, H. A. (Hossain Ali) ; Sharif University of Technology
    Horseradish peroxidase (HRP) was successfully immobilized on amine functionalized TiO2-coated multiwalled carbon nanotubes (NH2 – TiO2 – CNTs) by a convenient and efficient method. Electrochemical impedance spectroscopy, cyclic voltammetry and amperometry were applied to characterize the HRP/NH2 – TiO2 – CNT nano-composite. These techniques showed that the NH2 – TiO2 – CNTs greatly enhance the electron transfer between HRP and the modified electrode. Owing to the redox reaction of the electroactive centre of HRP, the HRP = NH2 – TiO2 – CNTs modified electrode exhibited a pair of quasi-reversible peaks with a peak-to-peak separation (ΔEp) of 70.6 mV and a formal potential (E 0′) of 367.65 mV... 

    Aluminothermic-carbothermal reduction synthesis of nano crystalline Al2O3-Ti(C,N) composite with different bed types

    , Article Iranian Journal of Materials Science and Engineering ; Volume 12, Issue 1 , 2015 , Pages 66-75 ; 17350808 (ISSN) Heydari Nasab, M ; Naghizadeh, R ; Samadi, H ; Nemati, A ; Sharif University of Technology
    Iran University of Science and Technology  2015
    Ceramic-matrix composites containing TiC-TiN have been used in a variety of application because of their superior properties such as high hardness, good wear resistance and high chemical stability. In this research, effect of coke and coke/calcium beds in synthesis of Al2O3-Ti(C, N) composites using alumino-carbothermic reduction ofTiO2 has been investigated. Al, TiO2 and active carbon with additives of extra carbon and NaCl and without additives, in separate procedures, have been mixed. Afterwards, mixtures were pressed and synthesized in 1200°C for 4hrs, in coke and coke/calcium beds, separately. Al2O3-Ti(C,N) composite was synthesized in ternary system of Al-TiO2-C with excess carbon and... 

    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  

    Modification of fretting fatigue behavior of AL7075-T6 alloy by the application of titanium coating using IBED technique and shot peening

    , Article Tribology International ; Volume 42, Issue 1 , 2009 , Pages 121-129 ; 0301679X (ISSN) Majzoobi, G. H ; Nemati, J ; Novin Rooz, A. J ; Farrahi, G. H ; Sharif University of Technology
    In this work, improvement in fretting fatigue life of AL7075-T6 has been investigated by titanium surface coating using ion-beam-enhanced deposition (IBED) technique and shot peening. From the experiments, the following conclusions were derived: (i) Shot peening increased the fretting fatigue life up to 350%. (ii) Titanium coating increased the fatigue life up to 100% with respect to virgin specimens for low working stresses, while it reduced the fatigue life at higher working stresses significantly. (iii) Titanium coating+shot peening increased the fatigue life up to 130% with respect to the virgin specimens for low working stresses, while it reduced the fatigue life at higher working... 

    Computational investigation of gas detection and selectivity on TiS3 nanoflakes supported by experimental evidence

    , Article Physical Chemistry Chemical Physics ; Volume 20, Issue 39 , 2018 , Pages 25458-25466 ; 14639076 (ISSN) Aryanpour, M ; Rafiefard, N ; Hosseini Shokouh, H ; Fardindoost, S ; Iraji Zad, A ; Sharif University of Technology
    Royal Society of Chemistry  2018
    Titanium trisulfide (TiS3), a transition metal chalcogenide, bears the potential to replace silicon, when taking the form of nanoflakes, due to its favorable band gap and optical response. In this paper, we investigate the response of TiS3 nanoflakes to gas detection through a careful quantum computational approach and a few succinct measurements. The computations are benchmarked and compared with a relevant experiment at each step, where their results/conclusions are discussed. The most stable surface of TiS3 particles is determined as (001), in agreement with the literature. The adsorption of 5 gas molecules is characterized through formulating and estimating their adsorption intensity... 

    Electrophoretic deposition of titanium dioxide nano-powders films in isopropanol as a solvent

    , Article International Journal of Modern Physics B ; Volume 22, Issue 18-19 , 2008 , Pages 2989-2994 ; 02179792 (ISSN) Ghorbani, M ; Roushan Afshar, M ; Sharif University of Technology
    World Scientific Publishing Co. Pte Ltd  2008
    In this study, titanium dioxide nano powders were electrophoretically deposited on the stainless steel in Isopropanol and Triethanolamine as a solvent and dispersant, respectively. The effects of deposition parameters including deposition voltage (5 to 20 V) and deposition time (5 to 60 s) on the microstructure and surface topography were examined by scanning electron microscope (SEM) and scanning probe microscope (SPM), respectively. In addition, the effects of these deposition parameters on packing density were investigated. This research revealed that substrate surface is fully covered with increasing deposition voltage and deposition time. Therefore packing density of deposited films is... 

    Growth of TiO2 nanoparticles by pulsed laser ablation (PLA) in liquid media and study of photocatalytic properties

    , Article International Journal of Modern Physics B ; Volume 22, Issue 18-19 , 2008 , Pages 3193-3200 ; 02179792 (ISSN) Shadmehr, S ; Mahdavi, S. M ; Taghavinia, N ; Azarian, A ; Sharif University of Technology
    World Scientific Publishing Co. Pte Ltd  2008
    We synthesized TiO2 nanoparticles by pulsed laser ablation of titanium target immersed in an aqueous solution of surfactant sodium dodecyl sulfate (SDS) or deionized water. The surfactant concentration dependence on size of TiO2 nanoparticles was investigated. The maximum amount of nanoparticles (with mean size of 40 nm in diameter) was obtained in an aqueous solution of 0.001 M SDS. We have also studied the effect of laser wavelength on growth of TiO2 nanoparticles. UV/visible spectroscopy and Scanning Electron Microscopy observations were employed for characterization of optical properties and particle sizes respectively. As TiO2 is a famous photocatalyst, we have also done photocatalytic... 

    Synthesis of Titanium Nanoparticles from Titanium Tetrachloride and Potassium Vapors Via Chemical Vapor Condensation Process

    , M.Sc. Thesis Sharif University of Technology Kookhaee, Hamed (Author) ; Halali, Mohammad (Supervisor)
    Titanium nanoparticles were synthesized by chemical vapor condensation (CVC) process. Titanium tetrachloride (TiCl4) as titanium’s precursor reacted with potassium as reductant, in vapor phase and the products were titanium nanoparticles encapsulated in potassium chloride. Dried Argon gas was employed as carrier gas. Resulting powders gathered in ethanol bath. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and atomic adsorption spectroscopy (AAS) analysis were used to characterizing the products. The effect of Argon gas flow on nanoparticles size was investigated in this research. The particle size decreases with increasing Argon gas flow. The size of nanoparticles was under... 

    Preparation and Characterization of Sol-Gel Derived Mesoporous TiO2 Nanostructured by Copolymer Templated

    , M.Sc. Thesis Sharif University of Technology Mozaffari, Naeimeh (Author) ; Mohammadi, Mohammad Reza (Supervisor) ; Faghihi Sani, Mohammad Ali (Supervisor)
    In recent years, mesoporous nanocrystalline TiO2 films have been regarded extensively. This kind of materials due to having unique surface area, structural and bulk properties, is used in many technological applications. In this work, a stable TiO2 sol was prepared using F127 Copolymer template and evaporation induced self-assembly method (EISA). The mesoporous TiO2 powders and thin films were then prepared. The as-deposited thin films were aged under five different conditions for 72h. Finally the samples were heat treated at 350°C, 400°C and 450°C. N2 adsorption/desorption results verified formation of mesoporous structure. Moreover, x-Ray diffraction patterns exhibited that the synthesized...