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    Optimized nanoporous alumina coating on AA3003-H14 aluminum alloy with enhanced tribo-corrosion performance in palm oil

    , Article Ceramics International ; Volume 46, Issue 6 , 2020 , Pages 7306-7323 Sarraf, M ; Nasiri Tabrizi, B ; Dabbagh, A ; Basirun, W. J ; Sukiman, N. L ; Sharif University of Technology
    Elsevier Ltd  2020
    This study aimed to prepare nanoporous anodic alumina on AA3003-H14 aluminum alloy using a mild anodization process with minimal working voltage and treatment time. The microstructural features, mechanical properties, and tribocorrosion behavior of the coatings were assessed to determine the optimum conditions for the fabrication of nanoporous anodic alumina on AA3003-H14 alloy. The microstructural analysis showed both uniform and nonuniform pore nucleations during anodization in H2SO4/C2H2O4, H2SO4/H2CrO4, and EG/H2O/NH4F electrolytes, where the optimal nanoporous structure with an average thickness, porosity, pore diameter, and interpore distance of 382 nm, 19%, 16 nm, and 35 nm,... 

    Study and full simulation of ten different gases on sealed Multi-Wire Proportional Counter (MWPC) by using Garfield and Maxwell codes

    , Article Applied Radiation and Isotopes ; Volume 115 , 2016 , Pages 289-294 ; 09698043 (ISSN) Ebrahimi Shohani, M ; Golgoun, S. M ; Aminipour, M ; Shabani, A ; Mazoochi, A. R ; Maghsoudi Akbari, A ; Mohammadzadeh, M ; Davarpanah, M. R ; Sardari, D ; Sadeghi, M ; Babapour Mofrad, F ; Jafari, A ; Sharif University of Technology
    Elsevier Ltd 
    In this research gas sealed Multi-Wire Proportional Counter (MWPC) including blades between anode wires and beta particles of 90Sr with 196 keV mean energy were considered. Ten different gases such as Noble gases mixtures with methane and several other pure gases were studied. In this type of detector, by using Garfield and Maxwell codes and for each of the gases, variation of different parameters such as first Townsend, electron attachment coefficients with variable electric field and their effects on pulse height or collected charge and in turn on Signal to Noise Ratio (SNR) were studied. Also the effect of anode voltage and its diameter and the pressure of gas on the pulse height were... 

    A theory for coupled lithium insertion and viscoplastic flow in amorphous anode materials for Li-ion batteries

    , Article Mechanics of Materials ; Volume 152 , 2021 ; 01676636 (ISSN) Bagheri, A ; Arghavani, J ; Naghdabadi, R ; Brassart, L ; Sharif University of Technology
    Elsevier B.V  2021
    Amorphous lithium metal alloys (LixM, with M=Si, Ge, Sn, …) are attractive anode materials for lithium-ion batteries owing to their high energy-storage capacity and safety characteristics. However, repeated insertion of lithium often leads to chemo-mechanical degradation of the alloy, which can severely reduce the battery capacity and cycle life. Better understanding of the chemo-mechanical response of lithium alloys is needed to guide the design of damage-resistant anode microstructures. In this work, we propose a constitutive theory that couples large, viscoplastic deformations to the insertion and extraction of lithium in amorphous electrode materials. The theory relies on the concept of... 

    Nickel-doped monoclinic WO3 as high performance anode material for rechargeable lithium ion battery

    , Article Journal of Electroanalytical Chemistry ; Volume 894 , 2021 ; 15726657 (ISSN) Rastgoo Deylami, M ; Javanbakht, M ; Omidvar, H ; Hooshyari, K ; Salarizadeh, P ; Askari, M. B ; Sharif University of Technology
    Elsevier B.V  2021
    The anode materials are one of the critical components in rechargeable lithium ion batteries (LIBs). The monoclinic tungsten trioxide (mWO3) is introduced as interesting anode electrode for LIBs due to its good structure for intercalation and de-intercalation of lithium ions, high abundance and various oxidation state of tungsten and etc. In this study, we prepare and investigate the effect of various amounts of nickel dopant on characteristics and electrochemical properties of the mWO3 as the anode electrode in a rechargeable LIB. The experimental investigations confirm that the number of nickel atoms has a remarkable effect on controlling spherical particle diameter, crystallite size, and... 

    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... 

    Design and Manufacture of Nanostructured Hydroxyapatite coated Foamy core@compact Shell Ti-6Al-4V Nanocomposite

    , M.Sc. Thesis Sharif University of Technology Ahmadi Seyedkhani, Shahab (Author) ; Sadrnezhad, Khatiboleslam (Supervisor)
    The main purpose of this research is design and manufacture of nanostructured hydroxyapatite-coated foamy core@compact shell Ti-6Al-4V bone-like composites for utilization as substitutive implant for cortical bone having porous core. The production procedure consist of two steps; (a) fabrication of foamy core@compact shell Ti-6Al-4V alloy using powder metallurgy-space holder technique, (b) precipitation of hydroxyapatite on the Ti-6Al-4V alloy specimens via pulse electrodeposition process. The bone-like structures were designed to reduce the stress shielding which ensures long-term stabilization of implants. It is while that, the hydroxyapatite coating improve the biological response of... 

    Using the Engineered Surface to Reduce the Adhesion Force of Ice to the Surface and Increase the Freezing Time of Water on the Surface

    , M.Sc. Thesis Sharif University of Technology Talebi Chavan, Reza (Author) ; Moosavi, Ali (Supervisor) ; Hosseini, Vahid (Supervisor)
    Ice formation upon various surfaces could lead to many industry problems and result in unpleasant accidents. For instance, the formation of ice on wind turbine blades or airplanes/helicopter wings could cause catastrophic disasters. The methods used to address this problem usually require exogenous energy consumption or anti-ice ingredients. The energy or anti-ice ingredients usage has adverse environmental effects and should be replaced with better approaches. One of these approaches is utilizing modified anti-ice surfaces. In this method, by modifying surface features, such as physical asperities and surface energy, the icing time of the surface could be prolonged. These surfaces are... 

    SnO2@a-Si core-shell nanowires on free-standing CNT paper as a thin and flexible Li-ion battery anode with high areal capacity

    , Article Nanotechnology ; Volume 28, Issue 25 , 2017 ; 09574484 (ISSN) Abnavi, A ; Sadati Faramarzi, M ; Abdollahi, A ; Ramzani, R ; Ghasemi, S ; Sanaee, Z ; Sharif University of Technology
    Institute of Physics Publishing  2017
    Here, we report 3D hierarchical SnO2 nanowire (NW) core-amorphous silicon shell on free-standing carbon nanotube paper (SnO2@a-Si/CNT paper) as an effective anode for flexible lithium-ion battery (LIB) application. This binder-free electrode exhibits a high initial discharge capacity of 3020 mAh g-1 with a large reversible charge capacity of 1250 mAh g-1 at a current density of 250 mA g-1. Compared to other SnO2 NW or its core-shell nanostructured anodes, the fabricated SnO2@a-Si/CNT structure demonstrates an outstanding performance with high mass loading (∼5.9 mg cm-2), high areal capacity (∼5.2 mAh cm-2), and large volumetric capacity (∼1750 mAh cm-3) after 25 cycles. Due to the... 

    On the growth sequence of highly ordered nanoporous anodic aluminium oxide

    , Article Materials and Design ; Volume 27, Issue 10 , 2006 , Pages 983-988 ; 02613069 (ISSN) Ghorbani, M ; Nasirpouri, F ; Iraji zad, A ; Saedi, A ; Sharif University of Technology
    Elsevier Ltd  2006
    Anodic aluminium oxide films were fabricated by well known two-step anodizing process in oxalic acid electrolyte. The ordering characteristics (ordered pore domains, average pore diameter size and through-pore arrangement) of anodic aluminium oxide films, obtained in different growth sequences, were identified by microscopic analysis such as ex situ contact-mode atomic force microcopy and scanning electron microscopy. Flattened areas in which some pits are seen mostly cover the electropolished surface of aluminium. Single anodizing of aluminium produces a broad distribution of nanopore size, whereas induces a highly ordered hemispherical pattern, which plays the ordered nucleation sites for... 

    Room temperature selective sensing of aligned Ni nanowires using impedance spectroscopy

    , Article Materials Research Express ; Volume 7, Issue 2 , 24 February , 2020 Mohammadi, M ; Fardindoost, S ; Iraji Zad, A ; Almasi Kashi, M ; Sharif University of Technology
    Institute of Physics Publishing  2020
    Room temperature gas sensing behavior of arrayed one-dimensional (1D) nickel nanowires (Ni NWs) are investigated using impedance spectroscopy. Ni nanowires synthesized via electrochemical deposition method based on anodic aluminum oxide (AAO) templates. Their structural characterization verified by scanning electron microscopy (SEM), x-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) analysis. Impedance spectroscopy as an essential technique utilized to understand the mechanism of gas interaction with the wires through the changes in their electronic behavior. Bode and Nyquist plots with the real and imaginary impedances are plotted versus frequency range of 500 Hz... 

    Experimental Studies for Construction of a Microbial Fuel Cell (MFC) in Continuous Flow Mode

    , M.Sc. Thesis Sharif University of Technology Sadeghi Haskoo, Mohammad Amin (Author) ; Vossoughi, Manoochehr (Supervisor) ; Aalemzadeh, Iran (Supervisor)
    In this research performance of microbial fuel cells (MFCs) in continuous flow mode was studied. Different anodic chambers were tested and it was found that granular activated carbons (GACs) produced the highest power density (1228 mW/m3) in comparison with multiple anodes (731 mW/m3), single anode (294 mW/m3) and polymeric packings (40 mW/m3). It was also shown that in a plug-anodic chamber (PAC) the power output is reduced by reducing agitation of anodic volume. Adding more GACs to anodic chamber results in power increase, however by increasing occupied volume from 80% to 100% the power increase was negligible in result of cathodic reactions limitations. Feed flowrate was increased from... 

    Effect of Solidification Rate of Copper Anodes on the Chemical and Electrochemical Dissolution during Electrorefining

    , M.Sc. Thesis Sharif University of Technology bagheri, Reza (Author) ; Yoozbashizadeh, Hossein (Supervisor)
    In the present work,the effect of solidification rate on the electrochemical behavior of copperanodes of Sarcheshmeh copper complex has been studied.Inthis regard, three cylindrical coppers pecimens with different solidificationrates casted into water-cooled metal mold (A specimen), metal mold (B specimen) and sand mold (C specimen). Cylinders for microstructural and electrochemical investigation, alongthickness dividedinto several specimens. To investigate themicrostructure of the specimens, opticalmicroscopyand scanning electron microscopy(SEM)were used. ICP testhasbeen usedforelemental analysis of each specimen; and eventuallytoinvestigate theelectrochemical behavior ofeach 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.... 

    Fabrication of Dental Implant from Ti-6Al-4V With Nanostructured Hydroxyapatite Coating

    , M.Sc. Thesis Sharif University of Technology Rahnamaee, Yahya (Author) ; Sadrnezhad, Khatiboleslam (Supervisor)
    The use of dental implants has grown considerably in recent years in Iran but this piece is the industrial imported parts that are not yet produced in Iran. So the main purpose of this research was to fabricate a dental implant from Ti-6Al-4V alloy by CNC machining techniques. On the other hand, the poor bonding strength of bioactive coatings and low cell growth on the surface of uncoated implants are the common problems in the use of dental implants. So another aim of this study was to investigate the effect of Nanoscale surface topography and nanostructured coatings on the surface modification of titanium implant in order to improve Osseointegration and the bonding strength of bioactive... 

    Hydroxyapatite Coating on Nanotubes TiO2

    , M.Sc. Thesis Sharif University of Technology Goodarzi, Mena (Author) ; Afshar, Abdollah (Supervisor) ; Dolati, Abolghasem (Supervisor)
    There are many techniques that have been used to create hydroxyapatite nanoparticles coating on nanotubes. Electrophoretic deposition (EPD) is one of the methods that has advantages of short formation time, needs simple apparatus, little restriction of the shape of substrate, no requirement for binder burnout as the green coating contains few or no organics. In the research, first, titanium dioxide nanotubes were fabricated by anodic oxidation. Anodizing voltage effect on the morphology of nanotubes was evaluated. SEM images was shown that in the anodizing voltage 20V, nanotubes were the most regular. Then, Hydroxyapatite nanoparticles has been deposited onto nanotublar TiO2 by... 

    Desulfurization of Petroleum Coke in Aluminium Industry

    , M.Sc. Thesis Sharif University of Technology Askari, Hadis (Author) ; Khorasheh, Farhad (Supervisor) ; Soltanali, Saeed (Supervisor) ; Baghalha, Morteza (Co-Advisor) ; Tayebi, Shokufeh (Co-Advisor)
    In this study, desulfurization of petroleum coke has been investigated for use in aluminum industry. To reduce sulfur content in petroleum coke, desulfurization has been investigated by two methods of solvent extraction and molten caustic leaching. The method of molten caustic leaching at temperatures of 400-600 °C has been investigated. Other effective parameters on the desulfurization of petroleum coke are the mass ratio of alkali to feed (petroleum coke) in the range of 0.5-1.5 and the time of 1-3 hour and the mesh size of 200-600 micron. In this study, the conditions of desulfurization of petroleum coke using potassium hydroxide have been investigated. Results show that by using the... 

    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... 

    Optimization of Nanostructures for Electron Emission

    , Ph.D. Dissertation Sharif University of Technology Yasrebi, Navid (Author) ; Rashidian, Bizhan (Supervisor)
    The need for better characterization systems (electron microscopes) and high resolution lithography systems, have made electron beams systems an interesting choice for research and development. In fact, all of the above applications require ideal electron beams (beams with minimum energy spread, maximum current density, and minimum spotsize), and electron-optic lenses (simple lenses with minimum aberration). In this research, theoretical aspects of electron emission and lens systems are reviewed. Field emission array (FEA) electron guns are introduced as electron sources with minimum energy spread, and a new simulation method is presented in order to minimize the complexity, and reduce the... 

    Influence of Cobalt and Vanadium Dopants on the Performance of TiO2(B) Nanowires used as anode Materials in Lithium-ion Batteries

    , M.Sc. Thesis Sharif University of Technology Amirsalehi, Mahmoud (Author) ; Askari, Masoud (Supervisor)
    Li-ion batteries have been widely applied as power sources for portable electronic devices. Recently, Li-ion batteries are considered as the most promising energy storage technology for electric vehicle applications however, fundamental improvements are needed. TiO2 (B) is attractive candidate for anodes in rechargeable Li-ion batteries, due to their low cost, non-toxicity and favorable channel structure for fast lithium mobility. It is predicted that synthesis of doped nanostructure of this material, through reducing the diffusion pathway and formation of crystal defects, will increase the capacity of TiO2(B). In this investigation, Co and V doped TiO2(B) nanowires are synthesized by... 

    AC Anodizing of Pure Titanium Grade 2 with HA Nano Particle

    , M.Sc. Thesis Sharif University of Technology Chambary, Ehsan (Author) ; Ghorbani, Mohammad (Supervisor)
    In this study, biocompatible ceramic coating, containing hydroxyapatite particles (HA), was successfully created by AC anodizing, on the surface of commercially pure titanium grades 2. Coating process basically consisted of three methods. In Method 1, samples were anodized in a salty electrolyte containing calcium – phosphate base and in method 2 samples were anodized as initial process, following cathodic polarisation deposition of HA particles. Finally in method 3, samples were anodized in an electrolyte containing of HA particles suspension.Parameters such as current density and time of anodizing process, in first procedure, and time of cathodic deposition process in second procedure, and...