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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...
Flexible free-standing vertically aligned carbon nanotube on activated reduced graphene oxide paper as a high performance lithium ion battery anode and supercapacitor
, Article Electrochimica Acta ; Volume 320 , 2019 ; 00134686 (ISSN) ; Abnavi, A ; Ghasemi, S ; Mohajerzadeh, S ; Sanaee, Z ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Here, controlled growth of vertically aligned carbon nanotubes (VACNTs) on free-standing porous activated reduced graphene oxide (a-rGO) paper was fabricated using plasma-enhanced chemical vapor deposition method. The electrochemical performance of prepared film was investigated to provide effective electrode for 3D flexible high-performance lithium-ion batteries (LIBs) and supercapacitors. The results revealed that the prepared electrode exhibited a high specific capacitance of 347 F/g at 0.5 A/g in 1 M KOH electrolyte, 60% more than non-activated rGO-paper (218 F/g). The VACNTs on a-rGO have increased the accessible surface area and acted as efficient electrical conducting paths, which...
Facile synthesis and simulation of MnO2 nanoflakes on vertically aligned carbon nanotubes, as a high-performance electrode for Li-ion battery and supercapacitor
, Article Electrochimica Acta ; Volume 390 , 2021 ; 00134686 (ISSN) ; Abnavi, A ; Ghasemi, F ; Ghasemi, S ; Sanaee, Z ; Mohajerzadeh, S ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
This study reports the successful fabrication of high-performance flexible binder-free lithium-ion battery anode and supercapacitor based on the synthesis of 3D hierarchical MnO2 nanoflakes (NFs) on vertically aligned carbon nanotubes (VACNTs) grown upon stainless steel (SS). The experimental results revealed that the prepared electrodes were well served as supercapacitors with a tremendous specific capacitance of MnO2 NFs VACNT/SS 1131 F/g at 0.25 A/g in 0.5 mol.L−1 Na2SO4, 518.8% more than VACNT/SS (218 F/g). Compared to other MnO2 NFs/CNT composites, as-fabricated binder-free MnO2 NFs/VACNTs electrode achieves outstanding performance with high initial discharge and charge capacities of...
Facile synthesis and simulation of MnO2 nanoflakes on vertically aligned carbon nanotubes, as a high-performance electrode for Li-ion battery and supercapacitor
, Article Electrochimica Acta ; Volume 390 , 2021 ; 00134686 (ISSN) ; Abnavi, A ; Ghasemi, F ; Ghasemi, S ; Sanaee, Z ; Mohajerzadeh, S ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
This study reports the successful fabrication of high-performance flexible binder-free lithium-ion battery anode and supercapacitor based on the synthesis of 3D hierarchical MnO2 nanoflakes (NFs) on vertically aligned carbon nanotubes (VACNTs) grown upon stainless steel (SS). The experimental results revealed that the prepared electrodes were well served as supercapacitors with a tremendous specific capacitance of MnO2 NFs VACNT/SS 1131 F/g at 0.25 A/g in 0.5 mol.L−1 Na2SO4, 518.8% more than VACNT/SS (218 F/g). Compared to other MnO2 NFs/CNT composites, as-fabricated binder-free MnO2 NFs/VACNTs electrode achieves outstanding performance with high initial discharge and charge capacities of...
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...
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...
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) ; Vaezi, M. R ; Sharif University of Technology
2004
Abstract
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) ; Vaezi, M. R ; Sharif University of Technology
Sharif University of Technology
2003
Abstract
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...
A novel and cost-effective method for fabrication of a durable superhydrophobic aluminum surface with self-cleaning properties
, Article Nanotechnology ; Volume 31, Issue 46 , 2020 ; Taghvaei, E ; Moosavi, A ; Sharif University of Technology
IOP Publishing Ltd
2020
Abstract
A hierarchical superhydrophobic surface is prepared via a two-step boiling water immersion process and anodization of the treated aluminum substrate in a novel hydrophobic electrolyte of aluminum nitrate and stearic acid mixture at room temperature. The immersion time in boiling water had a significant influence on the morphology and durability of the sample. A pseudoboehmite coating is created on the aluminum surface during the boiling process, as revealed by the field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared (FTIR) spectrophotometer results. The energy-dispersive x-ray spectroscopy analysis confirmed the formation of hydrophobic coating surface after...
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) ; Mohammadi, I ; Sadrnezhaad, S. K ; Sharif University of Technology
Elsevier
2016
Abstract
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...
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) ; Skeldon, P ; Zhou, X ; Ghorbani, M ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
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) ; Skeldon, P ; Zhou, X ; Hashimoto, T ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
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...
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...
Meta-analysis of bioenergy recovery and anaerobic digestion in integrated systems of anaerobic digestion and microbial electrolysis cell
, Article Biochemical Engineering Journal ; Volume 178 , 2022 ; 1369703X (ISSN) ; Arvin, A ; Feizi, A ; Dehdashti, B ; Torkian, A ; Sharif University of Technology
Elsevier B.V
2022
Abstract
In current study, a meta-analysis approach was used to identify and evaluate the impact of various factors on the performance of integrated systems of anaerobic digestion with microbial electrolysis cell. In this study, related articles on the topic were systematically identified and collected according to the considered criteria, and the effect size that refers to the value of the difference between variables mean (total chemical oxygen demand (TCOD) removal rate and CH4 yield) was estimated. According to the meta-analysis, fed-batch operation mode, the range of 20< temperature ≤30 °C, metal cathodes, the range of 500< anode surface area ≤5000 cm2, HRT (hydraulic retention time) >20 days,...
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...
Hydrothermal synthesis of TiO2 nanocrystals in different basic pHs and their applications in dye sensitized solar cells
, Article Physica E: Low-Dimensional Systems and Nanostructures ; Volume 70 , June , 2015 , Pages 113-120 ; 13869477 (ISSN) ; Marandi, M ; Taghavinia, N ; Sharif University of Technology
Elsevier
2015
Abstract
In this research TiO2 nanocrystals with sizes about 11-70 nm were grown by hydrothermal method. The process was performed in basic autoclaving pH in the range of 8.0-12.0. The synthesized anatase phase TiO2 nanocrystals were then applied in the phtoanode of the dye sensitized solar cells. It was shown that the final average size of the nanocrystals was larger when the growth was carried out in higher autoclaving pHs. The photoanodes made of TiO2 nanocrystals prepared in the pHs of 8.0 and 9.0 represented low amounts of dye adsorption and light scattering. The performance of the corresponding dye sensitized solar cells was also not acceptable. Nevertheless, the energy conversion efficiency...
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...
Effect of operating conditions on the performance of a PEM fuel cell
, Article International Journal of Heat and Mass Transfer ; Volume 144 , 2019 ; 00179310 (ISSN) ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In this study, a two-phase flow model based on species transport, energy, and electrochemical equations was developed for polymer electrolyte membrane fuel cell (PEMFC). The influences of heat sources and sinks, and water transport inside the fuel cell were also taken into account. In this regard, the effect of the operating conditions including cell temperature and pressure, anode and cathode inlet humidity, and anode and cathode stoichiometric ratios on the fuel cell performance was investigated. The simulation results show that inlet humidity and stoichiometric ratio of the anode side, cell pressure and temperature, and distribution of the heat sources and sinks are crucial factors...
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) ; Arghavani, J ; Naghdabadi, R ; Brassart, L ; Sharif University of Technology
Elsevier B.V
2021
Abstract
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...
Simulation analysis of inverted organic solar cells with grating structure: undesirable effects of high absorption near grating anode
, Article Optik ; Volume 154 , February , 2018 , Pages 453-458 ; 00304026 (ISSN) ; Faez, R ; Sharif University of Technology
Elsevier GmbH
2018
Abstract
An inverted organic solar cell (IOSC) with nanograting array as anode of the cell has been simulated and analyzed using a combined electrical and optical approach. We have used finite difference time domain (FDTD) method for optimizing device structure. We have compared the characteristics of the IOSC with grating structure with a reference IOSC without grating structure. As a result, an improvement of 11% and 26% in power conversion efficiency (PCE) and short circuit current (JSC) compared to the reference structure was achieved. An analysis is provided on the origin of reduced fill factor (FF) in the IOSC with grating structure. We also have discussed about disadvantage of using optical...