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    Fabrication of self-organised highly ordered titanium oxide nanotube arrays by anodic oxidation and characterisation

    , Article International Journal of Nanomanufacturing ; Volume 5, Issue 3-4 , 2010 , Pages 297-309 ; 17469392 (ISSN) Mohammadpour, R ; Ahadian, M. M ; Iraji Zad, A ; Taghavinia, N ; Dolati, A. G ; Sharif University of Technology
    Self-organised and vertically oriented titanium oxide nanotube array (TNTA) has been synthesised by potentiostat anodisation of Ti foil in fluoride-based electrolyte. By varying the anodisation voltage from 8 V to 24 V it was possible to gradually change the topologies of nanotubes. The size of TNTAs was measured using SEM images and also determined based on a non-destructive optical method. In addition, photoelectrochemical properties of nanotubular TiO2/Ti electrodes were examined by anodic photocurrent response, potentiodynamic polarisation measurements and electrochemical impedance spectroscopy. A general equivalent circuit model was proposed for photoelectrochemical system consists of... 

    Exhaustive denitrification via chlorine oxide radical reactions for urea based on a novel photoelectrochemical cell

    , Article Water research ; Volume 170 , 2020 , Pages 115357- Shen, Z ; Zhang, Y ; Zhou, C ; Bai, J ; Chen, S ; Li, J ; Wang, J ; Guan, X ; Rahim, M ; Zhou, B ; Sharif University of Technology
    NLM (Medline)  2020
    Urea is a major source of nitrogen pollution in domestic sewage and its denitrification is difficult since it is very likely to be converted into ammonia or nitrate instead of expected N2. Herein, we propose an exhaustive denitrification method for urea via the oxidation of amine/ammonia-N with chlorine oxide radical, which induced from a bi-functional RuO2//WO3 anode, and the highly selective reduction of nitrate-N on cathode in photoelectrochemical cell (PEC). Under illumination, the WO3 photoanode side promotes the quantities hydroxyl and reactive chlorine radical, and these radicals are immediately combined to stronger chlorine oxide radical by RuO2 side, which obviously enhances the... 

    Characterization of porous poly-silicon impregnated with Pd as a hydrogen sensor

    , Article Journal of Physics D: Applied Physics ; Volume 38, Issue 1 , 2005 , Pages 36-40 ; 00223727 (ISSN) Rahimi, F ; Iraji Zad, A ; Razi, F ; Sharif University of Technology
    Porous poly-silicon (PPS) samples, obtained by electrochemical anodization of p-type poly-silicon wafers, were doped with Pd by the electroless process. Rutherford backscattering spectroscopy shows that Pd has diffused a few micrometres into the PPS layer. Scanning electron microscopy and energy dispersive x-ray analysis results demonstrate the presence of Pd as dispersed clusters on the surface. The variation of the electrical resistance in the presence of dry air diluted with hydrogen at room temperature shows that Pd/PPS samples have the ability to sense hydrogen at levels down to several thousands of ppm. This value is far below the flammability limit of hydrogen gas. It was found that... 

    Synthesis and Characterization of CdS Modified TiO2 Nanotubes for Studying of Photoelectrochemical (PEC) Properties

    , M.Sc. Thesis Sharif University of Technology Qorbani, Mohammad (Author) ; Moshfegh, Alireza (Supervisor) ; Azimirad, Rouhollah (Supervisor)
    In this research, first thin films with nanostructures of titanium nanotube arrays (TNAs) synthesized by anodization under different applied voltage (20- 60 V) and different reaction times (120 and 200 min). The electrolyte solution for synthesizing the samples contained 90% ethylene glycol (EG), 10% DI water, 0.1 M NHR4RF and a little HR3RPOR4R to reach the pH to 5.6. The synthesized samples crystallized under annealing treatment at 500 °C (with heating rate of 9.5 °CminP -1 P). The scanning electron microscopy (SEM) analysis was indicate that the length and the inner diameter of the nanotubes have increased from 1.6 μm and 67 nm (for 30 V anodization and for 2h) to 4.2 μm and 125 nm (for... 

    Strength assessment and bonding study of aluminum short fiber-reinforced gypsum composites

    , Article International Journal of Damage Mechanics ; Volume 21, Issue 1 , January , 2012 , Pages 129-149 ; 10567895 (ISSN) Mohandesi, J. A ; Sangghaleh, A ; Nazari, A ; Sharif University of Technology
    In this study, tensile strength of gypsum-based composite with aluminum fibers up to 15 vol.% was studied. To increase the interfacial bond strength between fibers and matrix, aluminum fibers were anodized under different conditions. Single fiber pull-out tests were carried out to investigate the bond strength. The interface was examined by scanning electron microscope. The ability of the composites to withstand longitudinal tensile load was also studied by tensile tests of dog bone-shaped, randomly oriented fiber-reinforced gypsum. By the introduction of aluminum fibers in gypsum as a randomly oriented composite, considerable increment in the strength is achieved and the toughness of the... 

    Hierarchical Co3O4/Co(OH)2 nanoflakes as a supercapacitor electrode: experimental and semi-empirical model

    , Article ACS Applied Materials and Interfaces ; Volume 7, Issue 21 , 2015 , Pages 11172-11179 ; 19448244 (ISSN) Qorbani, M ; Naseri, N ; Moshfegh, A. Z ; Sharif University of Technology
    American Chemical Society  2015
    In this research, facile and low cost synthesis methods, electrodeposition at constant current density and anodization at various applied voltages, were used to produce hierarchical cobalt oxide/hydroxide nanoflakes on top of porous anodized cobalt layer. The maximum electrochemical capacitance of 601 mF cm-2 at scan rate of 2 mV s-1 was achieved for 30 V optimized anodization applied voltage with high stability. Morphology and surface chemical composition were determined by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analysis. The size, thickness, and density of nanoflakes, as well as length of the porous anodized Co layer were measured about 460 ± 45 nm,... 

    Modification of nanostructured anodized aluminum coatings by pulse current mode

    , Article Surface and Coatings Technology ; Volume 278 , 2015 , Pages 48-55 ; 02578972 (ISSN) Mohammadi, I ; Afshar, A ; Sharif University of Technology
    Elsevier  2015
    In this study, the effects of pulse current mode on corrosion resistance and mechanical properties of anodized coatings were explored. Thickness and hardness measurements, polarization and electrochemical impedance spectroscopy were employed to take mechanical and corrosion behaviors of the anodized coatings into consideration. Also, field-emission scanning electron microscopy (FE-SEM) was utilized to characterize the surface morphology of the coatings. It was shown that in short anodizing times, coating thickness is controlled by the heat concentrated on coating. Although at prolonged anodizing times, the coating thickness is affected by average current density. Hardness measurements showed... 

    Self-organized titanium oxide nanotubes prepared in phosphate electrolytes: Effect of voltage and fluorine concentration

    , Article ECS Transactions, 25 April 2010 through 30 April 2010 ; Volume 28, Issue 7 , April , 2010 , Pages 67-74 ; 19385862 (ISSN) ; 9781607681830 (ISBN) Mahshid, S ; Dolati, A ; Goodarzi, M ; Askari, M ; Ghahramaninezhad, A ; ECS All Divisions ; Sharif University of Technology
    TiO2 a nanotube array was prepared using an anodization process. The process proceeded in a two-electrode cell containing of platinum sheet as the cathode electrode. Two phosphate-base electrolyte solutions containing different amounts of HF and NH4F were prepared. Different concentration of fluorine ions were examined in respected electrolytes. Current transient techniques were used to produce the TiO2 nanotubes at constant voltage of 18-25V. It was revealed that anodization at 18-22V, in so-called electrolytes would end up to nano-tubular structure. However the tubular structure prepared at 20V and from phosphate electrolyte containing of 0.5 wt% NH4F as well as 0.5 wt% HF, was recognized... 

    Diffusion-controlled growth model for electrodeposited cobalt nanowires in highly ordered aluminum oxide membrane

    , Article ECS Transactions, 25 April 2010 through 30 April 2010, Vancouver, BC ; Volume 28, Issue 17 , 2010 , Pages 13-25 ; 19385862 (ISSN) ; 9781607681939 (ISBN) Ghahremaninezhad, A ; Dolati, A ; Sharif University of Technology
    This work studies the electrochemical growth behavior of cobalt nanowires in highly ordered aluminum oxide membrane. Considering the electrodeposition of metallic nanowires, cation concentration profile in each nano pore was calculated. With assumption of linear diffusion zone on the growing surface of nanowires, a modified Cottrell equation was evaluated. To confirm the model, the Co nanowires were electrodeposited into porous anodic aluminum oxide (AAO) templates and the mechanism of deposition was studied. Comparing the results of model and the experiments has proved the accuracy of the model. Also, it was observed that the growth of the Co nanowires was controlled mainly by diffusion... 

    Electrochemical oxidation of saccharose on copper (hydr)oxide-modified electrode in alkaline media

    , Article Cuihua Xuebao/Chinese Journal of Catalysis ; Volume 31, Issue 11 , 2010 , Pages 1351-1357 ; 02539837 (ISSN) Jafarian, M ; Rashvand Avei, M ; Danaee, I ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
    A stable copper (hydr)oxide-modified electrode was prepared in 0.5 mol/L NaOH solution by cyclic voltammetry in the range of -250 to 1000 mV. It can be used for electrochemical studies in the range of -250 to 1000 mV without interfering peaks because there is no oxidation of copper. During an anodic potential sweep, the electro-oxidation of saccharose on Cu occurred by the formation of CuIII and this reaction also occurred in the early stages of the reversed cycle until it is stopped by the negative potentials. A mechanism based on the electro-chemical generation of CuIII active sites and their subsequent consumption by saccharose was proposed, and the rate law and kinetic parameters were... 

    Selective voltammetric determination of d-penicillamine in the presence of tryptophan at a modified carbon paste electrode incorporating TiO2 nanoparticles and quinizarine

    , Article Journal of Electroanalytical Chemistry ; Volume 644, Issue 1 , Jan , 2010 , Pages 1-6 ; 15726657 (ISSN) Mazloum Ardakani, M ; Beitollahi, H ; Taleat, Z ; Naeimi, H ; Taghavinia, N ; Sharif University of Technology
    A carbon paste electrode (CPE) chemically modified with TiO2 nanoparticles and quinizarine (QZ) was used as a selective electrochemical sensor for the simultaneous determination of minor amounts of d-penicillamine (D-PA) and tryptophan (Trp). This modified electrode showed very efficient electrocatalytic activity for anodic oxidation of both d-PA and Trp. Substantial decreases of anodic overpotentials for both compounds made this analysis possible. Results of square wave voltammetry (SWV) using this modified electrode showed two well-resolved anodic waves for the oxidation of d-PA and Trp, which makes the simultaneous determination of both compounds possible. The peak potential for the... 

    Facile synthesis of titanium nitride-graphene nanocomposite and its improved rate-dependent electroactivity with respect to lithium storage

    , Article Materials Research Bulletin ; Volume 84 , 2016 , Pages 388-396 ; 00255408 (ISSN) Yousefi, E ; Ghorbani, M ; Dolati, A ; Yashiro, H ; Sharif University of Technology
    Elsevier Ltd 
    Titanium nitride/graphene nanocomposite as an anode material of lithium ion batteries has been fabricated through the reaction of TiCl4 and NaN3 in supercritical benzene medium followed by ammonia treating at 1000 °C for 10 h. The synthesized TiN/G nanocomposite depicts rate-dependent behavior in such a way that it shows specific capacity of 115 mAh g−1 when is cycled at higher rate (1.6 C) while it shows 76 mAh g−1 when is cycled initially at lower rate (0.2 C) and is subsequently subjected to higher rate (1.6 C). Moreover, TiN/G anode demonstrates capacity retention of 112%, 100%, and 70% after 250 cycles at charge/discharge rates of 1.6, 0.7, and 0.2 C, respectively. This unusual behavior... 

    Hydroxyapatite based and anodic titania nanotube biocomposite coatings: fabrication, characterization and electrochemical behavior

    , Article Surface and Coatings Technology ; Volume 287 , 2016 , Pages 67-75 ; 02578972 (ISSN) Ahmadi, S ; Mohammadi, I ; Sadrnezhaad, S. K ; Sharif University of Technology
    Elsevier  2016
    The main challenges of biological implants are suitable strength, adhesion, biocompatibility and corrosion resistance. This paper discusses fabrication, characterization and electrochemical investigation of anodized Ti6Al4V without and with a hydroxyapatite (HA) layer, HA/TiO2 nanoparticles (NPs) and HA/TiO2 nanotubes (HA/anodized). X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS) were used to characterize and compare properties of different samples. Dense HA with uniform distribution and 12.8 ± 2 MPa adhesive strength enhanced to 19.2 ± 4 MPa by the addition of TiO2 nanoparticles and enhanced to 23.1 ± 4 MPa by the... 

    All inorganic cesium lead iodide perovskite nanowires with stabilized cubic phase at room temperature and nanowire array-based photodetectors

    , Article Nano Letters ; Volume 17, Issue 8 , 2017 , Pages 4951-4957 ; 15306984 (ISSN) Waleed, A ; Tavakoli, M. M ; Gu, L ; Hussain, S ; Zhang, D ; Poddar, S ; Wang, Z ; Zhang, R ; Fan, Z ; Sharif University of Technology
    Alluring optical and electronic properties have made organometallic halide perovskites attractive candidates for optoelectronics. Among all perovskite materials, inorganic CsPbX3 (X is halide) in black cubic phase has triggered enormous attention recently owing to its comparable photovoltaic performance and high stability as compared to organic and hybrid perovskites. However, cubic phase stabilization at room temperature for CsPbI3 still survives as a challenge. Herein we report all inorganic three-dimensional vertical CsPbI3 perovskite nanowires (NWs) synthesized inside anodic alumina membrane (AAM) by chemical vapor deposition (CVD) method. It was discovered that the as-grown NWs have... 

    Highly-ordered TiO2 nanotubes decorated with Ag2O nanoparticles for improved biofunctionality of Ti6Al4V

    , Article Surface and Coatings Technology ; Volume 349 , 2018 , Pages 1008-1017 ; 02578972 (ISSN) Sarraf, M ; Dabbagh, A ; Abdul Razak, B ; Mahmoodian, R ; Nasiri Tabrizi, B ; Madaah Hosseini, H. R ; Saber Samandari, S ; Abu Kasim, N. H ; Abdullah, H ; Sukiman, N. L ; Sharif University of Technology
    Elsevier B.V  2018
    The nanotubular arrays of titanium dioxide (TiO2 NTs) have recently received considerable interest for fabrication of dental and orthopedic implants. However, their antibacterial activity requires substantial improvement for the potential infections minimization, without compromise of their biocompatibility. In this work, TiO2 NTs were developed on Ti6Al4V substrates via anodization at a constant potential of 60 V for 60 min, followed by heat treatment at 500 °C for 90 min. Physical vapor deposition (PVD) was further employed to decorate silver oxide nanoparticles (Ag2O NPs) on the nanotubular edges. The results indicated that the highly-ordered TiO2 NTs with decorated Ag2O NPs could promote... 

    Degradation based operational optimization model to improve the productivity of energy systems, case study: Solid oxide fuel cell stacks

    , Article Energy Conversion and Management ; Volume 158 , 2018 , Pages 81-91 ; 01968904 (ISSN) Parhizkar, T ; Hafeznezami, S ; Sharif University of Technology
    Elsevier Ltd  2018
    In the present study a comprehensive thermodynamic model and degradation based optimization framework for energy management of anode supported solid oxide fuel cell (SOFC) stacks are carried out. The optimization framework determines optimum operating conditions to maximize system productivity (energy generation over system lifetime) considering degradation mechanisms. The main degradation mechanisms in anode supported SOFCs are nickel coarsening and oxidation. In this study, the optimum operating conditions regarding these degradation mechanisms to achieve maximum productivity at different target lifetimes are derived. The results show that target lifetime has a significant impact on system... 

    Comparison of various anodization and annealing conditions of titanium dioxide nanotubular film on MB degradation

    , Article EPJ Applied Physics ; Volume 47, Issue 1 , 2009 ; 12860042 (ISSN) Mohammadpour, R ; Iraji Zad, A ; Ahadian, M. M ; Taghavinia, N ; Dolati, A ; Sharif University of Technology
    In this study the influence of morphology of vertically oriented titanium oxide nanotube arrays (TNTAs) on their photocatalytic activities was investigated. To obtain nanotubes with different morphologies, they were prepared at different anodization voltages. The size of TNTAs were measured using SEM images and also determined based on a non-destructive optical method; We demonstrate how the tubular geometry of the TNTAs can be used to adjust the optical and also the wetting properties of them and how these properties affect the performance of the nanostructure in further applications as a photocatalyst. To investigate their potentials for environmental applications, the photocatalytic... 

    Synthesis of titanium oxide nanotubes and their decoration by MnO nanoparticles for biomedical applications

    , Article Ceramics International ; Volume 45, Issue 15 , 2019 , Pages 19275-19282 ; 02728842 (ISSN) Esmaeilnejad, A ; Mahmoudi, P ; Zamanian, A ; Mozafari, M ; Sharif University of Technology
    Elsevier Ltd  2019
    In this study, apatite formation ability on TiO2 nanotubes (TNTs) synthesized by anodizing process were compared with TNTs decorated by MnO nanoparticles. The MnO nanoparticles used for decoration process were fabricated via thermal decomposition method. At first, it was strived to find the optimal condition of anodizing process and the effect of applied voltages (15 V, 20 V, and 25 V) and process times (15 min, 20 min, and 25 min) on the diameter of the synthesized TNTs was investigated. Results of microscopic characterizations showed that the completely uniform structure of nanotubes with a diameter in the range of about 100–130 nm was achieved after 20 min of anodizing process at an... 

    Influence of PEO and mechanical keying on the strength of AA 5052 alloy/polypropylene friction stir spot welded joints

    , Article International Journal of Adhesion and Adhesives ; Volume 92 , 2019 , Pages 65-72 ; 01437496 (ISSN) Aliasghari, S ; Skeldon, P ; Zhou, X ; Ghorbani, M ; Sharif University of Technology
    Elsevier Ltd  2019
    A study has been carried out of the effect of plasma electrolytic oxidation (PEO)on the strength of AA 5052 alloy/polypropylene joints prepared using friction stir spot welding (FSSW). The joint strengths were determined using lap-shear tests and failure modes were investigated using scanning electron microscopy. Comparisons were made between control joints prepared with the alloy in the as-rolled condition or the as-rolled condition with a mechanical key and with PEO-treated alloy, with or without a mechanical key. Mechanical keying alone, provided by infiltration of polymer into holes of either 3 or 4.5 mm diameter drilled in the alloy, yielded enhancements of the joint strength by a... 

    Effect of an anodizing pre-treatment on AA 5052 alloy/polypropylene joining by friction stir spot welding

    , Article Materials Science and Engineering B: Solid-State Materials for Advanced Technology ; Volume 245 , 2019 , Pages 107-112 ; 09215107 (ISSN) Aliasghari, S ; Skeldon, P ; Zhou, X ; Hashimoto, T ; Sharif University of Technology
    Elsevier Ltd  2019
    A study has been carried out of the effect of an anodizing pre-treatment in a sulphuric acid electrolyte on the strength of AA 5052 alloy/polypropylene joints prepared using friction stir spot welding. Lap-shear tests were used to determine the joint strength. Comparisons were made with joints pre-treated using sand blasting. The failed specimens were examined by scanning and transmission electron microscopy. Anodizing improved the strength of the joints by a factor of about 6 compared with sandblasting. For the anodizing pre-treated joints, melted polymer infiltrated deeply within the nanoporous anodic film, forming a strong polymer-film bond. Joint failure occurred by ductile tearing of...