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Design and Manufacture of Nanostructured Hydroxyapatite coated Foamy core@compact Shell Ti-6Al-4V Nanocomposite
, M.Sc. Thesis Sharif University of Technology ; Sadrnezhad, Khatiboleslam (Supervisor)
Abstract
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...
Electrochemical Behaviors of RuO2-TiO2 Mixed Metal Oxide Coated on Titanium Anodes in Chlor-Alkali Electrolysis
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
Titanium anodes activated by noble metal oxides under the trade name of dimensionally stable anodes (DSAs) are widely used in the electrolytic industry, particularly in chlor – alkali electrolysis. Over 20 years of use, the fundamental aspects of their long – lasting performance are not fully understand and the corrosion mechanisms are still the subject of many investigations. RuO2 – TiO2 coatings on titanium substrate, due to proper electrochemical characteristics and good corrosion resistance, is most applicable as an anode in chlor – alkali systems. In the present investigation, the first layer of Pt – Ir coating is applied via electrodeposition method on the pretreated titanium substrate...
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) ; Tavakoli, M. M ; Gu, L ; Hussain, S ; Zhang, D ; Poddar, S ; Wang, Z ; Zhang, R ; Fan, Z ; Sharif University of Technology
Abstract
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...
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) ; Sadati Faramarzi, M ; Abdollahi, A ; Ramzani, R ; Ghasemi, S ; Sanaee, Z ; Sharif University of Technology
Institute of Physics Publishing
2017
Abstract
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...
Improving transparency in dye-sensitized nanostructured solar cells by optimizing nano-porous titanium dioxide photo-electrode
, Article Journal of Materials Science: Materials in Electronics ; Volume 28, Issue 11 , 2017 , Pages 7811-7818 ; 09574522 (ISSN) ; Mohammadpour, R ; Kasaeian, A ; Zebhi, Z ; Sharif University of Technology
Springer New York LLC
2017
Abstract
Today’s the technology based on dye-sensitized solar cells (DSSCs) has an important role in all photovoltaic system technologies. DSSCs can generate electricity with various degrees of transparency; this makes it suitable for use in various industries, especially in construction industry as smart windows. In fact DSSC can produce electricity and having natural light, simultaneously. It is obvious that DSSCs need to absorb solar radiation as much as possible. Since, the effective use of all incident lights leads to an increase in cell efficiency and this increase in efficiency is related to the amount of dye adsorbed on the surface of nanostructured electrode, so higher amount of dye for...
A non-catalytic vapor growth regime for organohalide perovskite nanowires using anodic aluminum oxide templates
, Article Nanoscale ; Volume 9, Issue 18 , 2017 , Pages 5828-5834 ; 20403364 (ISSN) ; Waleed, A ; Gu, L ; Zhang, D ; Tavakoli, R ; Lei, B ; Su, W ; Fang, F ; Fan, Z ; Sharif University of Technology
Royal Society of Chemistry
2017
Abstract
In this work, a novel and facile synthesis process to fabricate single crystalline organometal halide perovskite nanowires has been successfully developed. Nanowires were grown in a high density ordered array from metal nanoclusters inside anodic aluminum oxide templates using a non-catalytic chemical vapor deposition method. Specifically, perovskite NWs were grown as a result of the reaction between methylammonium iodide (MAI) and the Pb/Sn (Pb or Sn) metal in anodic aluminum oxide templates under optimal conditions. The characterization results show that there is a reaction zone at the interface between the perovskite material and metal, at the bottom of the anodic aluminum oxide...
Organic halides and nanocone plastic structures enhance the energy conversion efficiency and self-cleaning ability of colloidal quantum dot photovoltaic devices
, Article Journal of Physical Chemistry C ; Volume 121, Issue 18 , 2017 , Pages 9757-9765 ; 19327447 (ISSN) ; Simchi, A ; Tavakoli, R ; Fan, Z ; Sharif University of Technology
American Chemical Society
2017
Abstract
This paper presents solid-state ligand exchange of spin-coated colloidal lead sulfide quantum dot (PbS QD) films by methylammonium iodide (MAI) and integration of them in depleted heterojunction solar (DHS) devices having an antireflecting (AR) nanocone plastic structure. Time-resolved photoluminescence measurements determine a shorter lifetime of the charge carries on a semiconductor (TiO2) electron transfer layer for the MAI-passivated QD films as compared with those with long-chain aliphatic or short thiol ligands. Consequently, the DHS device yields improved power conversion efficiency (>125%) relative to oleic-acid-passivated PbS QD films. Using anodized aluminum oxide templates, an...
TiO2–BaTiO3 nanocomposite for electron capture in dye-sensitized solar cells
, Article Journal of the American Ceramic Society ; Volume 100, Issue 5 , 2017 , Pages 2144-2153 ; 00027820 (ISSN) ; Mohammadi, M. R ; Sharif University of Technology
Blackwell Publishing Inc
2017
Abstract
Different compositions of TiO2–BaTiO3 nanocomposites are synthesized with various weight ratios for dye-sensitized solar cell (DSSC) applications. TiO2 and BaTiO3 nanoparticles (NPs) are synthesized by sol-gel and solvothermal methods, respectively and are employed as the photoanode electrodes. BaTiO3 NPs have pure cubic perovskite crystal structure with an average size of 20-40 nm, while TiO2 NPs show pure anatase phase with 15-30 nm size. The power conversion efficiency (PCE) enhancement of the cells is first attained by controlling the thickness of the films for light harvesting improvement. The fabricated DSSC composed of pure BaTiO3 NPs with an optimal thickness of 25 μm shows...
Desulfurization of Petroleum Coke in Aluminium Industry
, M.Sc. Thesis Sharif University of Technology ; Khorasheh, Farhad (Supervisor) ; Soltanali, Saeed (Supervisor) ; Baghalha, Morteza (Co-Advisor) ; Tayebi, Shokufeh (Co-Advisor)
Abstract
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...
Long term performance degradation analysis and optimization of anode supported solid oxide fuel cell stacks
, Article Energy Conversion and Management ; Volume 133 , 2017 , Pages 20-30 ; 01968904 (ISSN) ; Roshandel, R ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
The main objective of this work is minimizing the cost of electricity of solid oxide fuel cell stacks by decelerating degradation mechanisms rate in long term operation for stationary power generation applications. The degradation mechanisms in solid oxide fuel cells are caused by microstructural changes, reactions between lanthanum strontium manganite and electrolyte, poisoning by chromium, carburization on nickel particles, formation of nickel sulfide, nickel coarsening, nickel oxidation, loss of conductivity and crack formation in the electrolyte. The rate of degradation mechanisms depends on the cell operating conditions (cell voltage and fuel utilization). In this study, the degradation...
Photoresponse enhancing in nanostructured WO3films by slight change in heating ambient
, Article Journal of Alloys and Compounds ; Volume 693 , 2017 , Pages 871-875 ; 09258388 (ISSN) ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
Providing solar hydrogen as a clean energy resource is one of the human challenges for future. Controlling oxygen vacancies as well as surface morphology in metal oxide semiconductors enables developing PEC H2production in some understood ways. Here, the influence of simple change in annealing atmosphere, air and pure oxygen, on photoresponse of nanocrystalline WO3has been studied completely. Results revealed that such slight change in annealing procedure increases effective surface interface and donor density by 77 and 72%, respectively. These effects and also retarding recombination of photogenerated electro-hole pair resulted in photocurrent enhancement under solar like illumination more...
Study on the morphology and photocatalytic activity of TiO2 nanotube arrays produced by anodizing in organic electrolyte with Ni, Na, and C as dopants
, Article Journal of Solid State Electrochemistry ; Volume 22, Issue 12 , 2018 , Pages 3883-3893 ; 14328488 (ISSN) ; Yoozbashizadeh, H ; Sharif University of Technology
Abstract
The main purpose of this research work is to investigate the effect of nickel as metal dopant on the morphology and photocatalytic activity of TiO2 nanotube arrays synthesized in the organic electrolyte by anodizing process containing sodium carbonate as an additive (TNAS). In order to characterize the synthesized nanotubes, various analyses such as FESEM, XRD, FTIR, XPS, DRS, and EIS were applied. The results of XPS and FTIR tests evaluate the participation of sodium (Na), nickel (Ni), and carbon (C) in the lattice of nanotubes as dopants. According to the DRS and UV-visible tests results, the band gap energy of TiO2 nanotube arrays decreases from 3.20 to ~ 2.64 eV as well as the absorption...
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) ; 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
Abstract
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...
Loading drug on nanostructured Ti6Al4V-HA for implant applications
, Article International Journal of Engineering, Transactions B: Applications ; Volume 31, Issue 8 , 2018 , Pages 1159-1165 ; 1728144X (ISSN) ; Sadrnezhaad, S. K ; Sharif University of Technology
Materials and Energy Research Center
2018
Abstract
Arrayed Ti6Al4V nanotubes (TNT) coated with hydroxyapatite (HA) were synthesized via electrochemical anodization method. Paracetamol was loaded onto TNT-HA electrode. Effects of anodization, nanotube formation and hydroxyapatite deposition on sorption and release of the drug were investigated. Saturation time of paracetamol on the anodized samples was 30% shorter than the hydroxyapatite-coated samples. Release behavior of the loaded drug was studied by (a) plunging the probe into phosphate buffered saline (PBS), (b) sampling the drug-loaded PBS at different times and (c) analyzing the solution via ultraviolet-visible (UV-vis) spectroscopy. Results showed that HA electrodes hold higher...
Influence of vanadium, cobalt-codoping on electrochemical performance of titanium dioxide bronze nanobelts used as lithium ion battery anodes
, Article Journal of Materials Science: Materials in Electronics ; 2018 , Pages 1-9 ; 09574522 (ISSN) ; Askari, M ; Sharif University of Technology
Springer New York LLC
2018
Abstract
In this work, V, Co-codoped TiO2(B) samples are synthesized through a hydrothermal method, and used as negative electrode materials for lithium ion batteries. The amount of dopants is varied in order to investigate their influence on electrochemical properties. The formation of V, Co-codoped TiO2(B) nanobelts with widths of 20 and 60 nm is demonstrated using X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma–optical emission spectrometry and field-emission scanning electron microscopy analyses. In addition, the electrochemical properties of the samples are tested by cyclic voltammetry, charging/discharging, and cyclic performance techniques. Compared to other...
SnO2 nanowires on carbon nanotube film as a high performance anode material for flexible Li-ion batteries
, Article Journal of Nanostructures ; Volume 8, Issue 3 , 2018 , Pages 288-293 ; 22517871 (ISSN) ; Faramarzi, M. S ; Sanaee, Z ; Ghasemi, S ; Sharif University of Technology
University of Kashan
2018
Abstract
Today, Li-ion batteries (LIBs) are the most common rechargeable batteries used in electronic devices. SnO2 with theoretical specific capacity of 782 mAh/g is among the best anode materials for LIBs. In this report, Threedimensional SnO2 nanowires (NWs) on carbon nanotube (CNT) thin film (SnO2 / CNT) is fabricated using a combination of vacuum filtration and thermal evaporation techniques. The resulting 3D heterostructure SnO2/CNT was characterized by X-ray diffraction, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). This fabricated SnO2/CNT electrode has been tested as a flexible and binderfree anode for LIB, which exhibits high initial discharge/charge...
An electrochemical synthesis of reduced graphene oxide/zinc nanocomposite coating through pulse-potential electrodeposition technique and the consequent corrosion resistance
, Article International Journal of Corrosion ; Volume 2018 , 2018 ; 16879325 (ISSN) ; Afshar, A ; Yaghoubinezhad, Y ; Sharif University of Technology
Hindawi Limited
2018
Abstract
Pulse-potential coelectrodeposition of reduced graphene oxide/zinc (rGO-Zn) nanocomposite coating is directly controlled upon a steel substrate from a one-pot aqueous mixture containing [GO-/Zn2+]δ+ nanoclusters. GO nanosheets are synthesized by modified Hummer's approach while Zn cations are produced in the solution and deposited on GO nanosheets using anodic dissolution technique. Eventually, nanoclusters are reduced to rGO-Zn film through an electrochemical process. Chemical composition, surface morphology, and corrosion resistance of the thin film are characterized. Results show that the corrosion resistance of rGO-Zn coating is approximately 10 times more than the bare steel. © 2018 S....
Nanotextured spikes of α-Fe2O3/NiFe2O4 composite for efficient photoelectrochemical oxidation of water
, Article Langmuir ; Volume 34, Issue 12 , 2018 , Pages 3555-3564 ; 07437463 (ISSN) ; Tavakoli, M. M ; Waleed, A ; Virk, U. S ; Yang, S ; Waseem, A ; Fan, Z ; Nadeem, M. A ; Sharif University of Technology
American Chemical Society
2018
Abstract
We demonstrate for the first time the application of p-NiFe2O4/n-Fe2O3 composite thin films as anode materials for light-assisted electrolysis of water. The p-NiFe2O4/n-Fe2O3 composite thin films were deposited on planar fluorinated tin oxide (FTO)-coated glass as well as on 3D array of nanospike (NSP) substrates. The effect of substrate (planar FTO and 3D-NSP) and percentage change of each component (i.e., NiFe2O4 and Fe2O3) of composite was studied on photoelectrochemical (PEC) water oxidation reaction. This work also includes the performance comparison of p-NiFe2O4/n-Fe2O3 composite (planar and NSP) devices with pure hematite for PEC water oxidation. Overall, the nanostructured...
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) ; Hafeznezami, S ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
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...
Alumina feeding system changes in aluminum electrochemical cell with d18 technology for energy efficiency (Case study: Almahdi-hormozal aluminum smelter)
, Article 147th Annual Meeting and Exhibition of the Minerals, Metals and Materials Society, TMS 2018, 11 March 2018 through 15 March 2018 ; Volume Part F12 , 2018 , Pages 721-728 ; 23671181 (ISSN); 9783319725253 (ISBN) ; Samimi, A ; Baharvand, B ; Sharif University of Technology
Springer International Publishing
2018
Abstract
Aluminum reduction cells have benefited from point feeding technology for a long time, but there are still smelters which are using the old technology of center break and center feed system. Due to several factors this system is no longer approved and there have been a few attempts worldwide to upgrade these cells so as to implement the newer technology by applying mechanical and automation changes. In this paper we will present an attempt which was made in order to retrofit a so-called center break cell to point feeder cell. The results show that this project has decreased the energy consumption and anode effect frequency. Furthermore, there has been a significant increase in current...