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Electrophoretic encapsulation for slow release of vancomycin from perpendicular TiO2 nanotubes grown on Ti6Al4V electrodes
, Article Materials Research Express ; Volume 6, Issue 12 , 2019 ; 20531591 (ISSN) ; https://iopscience.iop.org/article/10.1088/2053-1591/ab6c98 ; Ahmadi Seyedkhani, S ; Sadrnezhaad, S. K ; Sharif University of Technology
Institute of Physics Publishing
2019
Abstract
Ordered perpendicular TiO2 nanotubes (TNT) with 405 to 952 nm length and 60 to 90 nm diameter were grown via 40 to 120 min anodization of Ti6Al4V flat substrates. The samples were called TNT-40, -60, -80, -100, and -120. Vancomycin was loaded on the bare and anodized electrodes by separate immersion and electrophoretic (EP) deposition procedures. EP loading resulted in storage capacity of 5221.86 μg cm-2 for TNT-80 which was much higher than 1036.75 μg cm-2 of immersed sample. Drug release comprised of three stages: (i) burst release (78% for the bare, and 23% for the TNT-80 sample), (ii) gradual transport (21% for the bare, and 64% for the TNT-80 sample), and (iii) equilibrium. Transfer...
Electrophoretic encapsulation for slow release of vancomycin from perpendicular TiO2 nanotubes grown on Ti6Al4V electrodes
, Article Materials Research Express ; Volume 6, Issue 12 , 2019 ; 20531591 (ISSN) ; Ahmadi Seyedkhani, S ; Sadrnezhaad, S. K ; Sharif University of Technology
Institute of Physics Publishing
2019
Abstract
Ordered perpendicular TiO2 nanotubes (TNT) with 405 to 952 nm length and 60 to 90 nm diameter were grown via 40 to 120 min anodization of Ti6Al4V flat substrates. The samples were called TNT-40, -60, -80, -100, and -120. Vancomycin was loaded on the bare and anodized electrodes by separate immersion and electrophoretic (EP) deposition procedures. EP loading resulted in storage capacity of 5221.86 μg cm-2 for TNT-80 which was much higher than 1036.75 μg cm-2 of immersed sample. Drug release comprised of three stages: (i) burst release (78% for the bare, and 23% for the TNT-80 sample), (ii) gradual transport (21% for the bare, and 64% for the TNT-80 sample), and (iii) equilibrium. Transfer...
Study the failure of casted copper anode: The formation of bumps defects on the surface of the anode during casting
, Article Engineering Failure Analysis ; Volume 138 , 2022 ; 13506307 (ISSN) ; Reza Khayati, G ; Javad Khorasani, S. M ; Assadat Yaghubi, N ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Copper anode (∼98%) is widely used to produce the cathode (99.995 wt%) in electrorefining process. These anodes sometimes become problematic from the production line due to the presence of bumps/holes on their surface. To find the reason of this defect, chemical composition of the three casted anodes was determined by the quantmeter analysis. Also, the microscopic and phase analysis were done by FESEM, EDS, XRD, and XRF for three types of anodes bump. The chemical analysis of anodes confirmed a high level of sulfur and oxygen, which have a key role in the formation of bumps. The results confirmed the presence of impurities including Cu2S, BaSO4, CaCO3 and MgCO3, which cause the formation of...
Facile synthesis of petal-like NiCo/NiO-CoO/nanoporous carbon composite based on mixed-metallic MOFs and their application for electrocatalytic oxidation of methanol
, Article Applied Catalysis B: Environmental ; Volume 244 , 2019 , Pages 802-813 ; 09263373 (ISSN) ; Shahrokhian, S ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Porous carbon template decorated with mixed transition metals/metal oxides with tunable architecture is becoming increasingly important and attractive as a kind of novel electrode materials. In this way, mixed-metallic metal-organic frameworks (MOFs) provide an opportunity for fabrication of homogeneous mixed metals/metal oxides distribution in the porous carbon frame without any carbon precursor additive. Also, structures, dimensions and electrochemical performance of MOFs can be readily manipulated by simply tuning the metals molar ratio. In this study, we demonstrate the design and fabrication of petal-like NiCo/NiO-CoO metal/metal oxides with a rational composition embedded in 3D...
Nickel-doped monoclinic WO3 as high performance anode material for rechargeable lithium ion battery
, Article Journal of Electroanalytical Chemistry ; Volume 894 , 2021 ; 15726657 (ISSN) ; Javanbakht, M ; Omidvar, H ; Hooshyari, K ; Salarizadeh, P ; Askari, M. B ; Sharif University of Technology
Elsevier B.V
2021
Abstract
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...
Voltammetric monitoring of Cd (II) by nano-TiO2 modified carbon paste electrode sensitized using 1,2-bis-[o-aminophenyl thio] ethane as a new ion receptor
, Article Sensors and Actuators, B: Chemical ; Vol. 192 , 2014 , pp. 648-657 ; ISSN: 09254005 ; Ghobadi, M ; Bideh, B. N ; Sharif University of Technology
Abstract
The objective of the work ahead is presentation of a new carbon paste electrode (CPE) modified by TiO2 nanoparticles (TiO2NPs) and 1,2-bis-[o-aminophenyl thio] ethane (APTE) ligand as a selective cation receptor for determination of the Cd (II) ions using differential pulse anodic stripping voltammetry (DPASV). The electrode shows an excellent tendency to Cd (II) ions in presence of some interfering species. Under the optimum conditions, a linear calibration curve was obtained in the concentration range of 2.9 nM to 4.6 μM with a correlation coefficient of 0.9969 in the anodic potential of 0.54 (V vs. Ag/AgCl). The metal detection limit was 2.0 nM after 10 min preconcentration (S/N = 3). The...
Bioinspired multifunctional TiO2 hierarchical micro/nanostructures with tunable improved bone cell growth and inhibited bacteria adhesion
, Article Ceramics International ; Volume 46, Issue 7 , 2020 , Pages 9669-9679 ; Bagheri, R ; Vossoughi, M ; Ahmadi Seyedkhani, S ; Samadikuchaksaraei, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Two main origins of failure for hard tissue replacements are structural loosening and prosthetic implant infections (PIIs). Bioinspired multifunctional TiO2 hierarchical micro/nanostructures of conical-shaped TiO2 (CTO), regular TiO2 nanotubes (RTO) and irregular TiO2 nanotubes (ITO) with tunable improved cell growth and inhibited bacteria adhesion were synthesized. CTO and ITO samples indicated superhydrophilicity with contact angles of less than 5°. The MTT assay demonstrated excellent biological performance for RTO and CTO sample with 98.1% and 103.1% of cell viability, respectively. The bridging force for osteoblast cell attachment onto the synthesized porous coatings was presented as a...
Bioinspired TiO2/chitosan/HA coatings on Ti surfaces: Biomedical improvement by intermediate hierarchical films
, Article Biomedical Materials (Bristol) ; Volume 17, Issue 3 , 2022 ; 17486041 (ISSN) ; Ahmadi Seyedkhani, S ; Eslami Saed, A ; Sadrnezhaad, S. K ; Seza, A ; Sharif University of Technology
Institute of Physics
2022
Abstract
The most common reasons for hard-tissue implant failure are structural loosening and prosthetic infections. Hence, in this study, to overcome the first problem, different bioinspired coatings, including dual acid-etched, anodic TiO2 nanotubes array, anodic hierarchical titanium oxide (HO), micro- and nanostructured hydroxyapatite (HA) layers, and HA/chitosan (HA/CS) nanocomposite, were applied to the titanium alloy surfaces. X-ray diffraction and FTIR analysis demonstrated that the in situ HA/CS nanocomposite formed successfully. The MTT assay showed that all samples had excellent cell viability, with cell proliferation rates ranging from 120% to 150% after 10 days. The HO coating...
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) ; Iraji Zad, A ; Razi, F ; Sharif University of Technology
2005
Abstract
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...
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) ; Naseri, N ; Moshfegh, A. Z ; Sharif University of Technology
American Chemical Society
2015
Abstract
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,...
Ti-rich TiO2 tubular nanolettuces by electrochemical anodization for all-solid-state high-rate supercapacitor devices
, Article ChemSusChem ; Volume 12, Issue 17 , 2019 , Pages 4064-4073 ; 18645631 (ISSN) ; Khajehdehi, O ; Sabbah, A ; Naseri, N ; Sharif University of Technology
Wiley-VCH Verlag
2019
Abstract
Supercapacitors store charge by ion adsorption or fast redox reactions on the surface of porous materials. One of the bottlenecks in this field is the development of biocompatible and high-rate supercapacitor devices by scalable fabrication processes. Herein, a Ti-rich anatase TiO2 material that addresses the above-mentioned challenges is reported. Tubular nanolettuces were fabricated by a cost-effective and fast anodization process of Ti foil. They attained a large potential window of 2.5 V in a neutral electrolyte owing to the high activation energy for water splitting of the (1 0 1) facet. Aqueous and all-solid-state devices showed diffusion time constants of 46 and 1700 ms, as well as...
New protein-based hydrogel with superabsorbing properties: Effect of monomer ratio on swelling behavior and kinetics
, Article Industrial and Engineering Chemistry Research ; Volume 47, Issue 23 , 2008 , Pages 9206-9213 ; 08885885 (ISSN) ; Salimi, H ; Sharif University of Technology
2008
Abstract
In this paper we report an efficient synthesis of hydrolyzed collagen-g-poly(sodium acrylate-co-2-hydroxyethyl aery late) hydrogel through chemical cross-linking by graft copolymerization of these two monomers onto the protein backbone in the presence of a cross-linker. Infrared spectroscopy and thermogravimetric analysis (TGA) were carried out to confirm the chemical structure of the hydrogel. Moreover, morphology of the samples was examined by scanning electron microscopy (SEM). To investigate the effect of monomer ratio on swelling behavior in various media three hydrogels with different acrylic acid/2-hydroxyethyl acrylate (AA/HEA) weight ratios were synthesized and swelling capacity was...
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...
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...
Effect of samarium oxide on the electrical conductivity of plasma-sprayed SOFC anodes
, Article JOM ; Volume 68, Issue 10 , 2016 , Pages 2569-2573 ; 10474838 (ISSN) ; Samadi, H ; Nemati, A ; Sharif University of Technology
Minerals, Metals and Materials Society
Abstract
Solid oxide fuel cells (SOFCs) are rapidly becoming recognized as a new alternative to traditional energy conversion systems because of their high energy efficiency. From an ecological perspective, this environmentally friendly technology, which produces clean energy, is likely to be implemented more frequently in the future. However, the current SOFC technology still cannot meet the demands of commercial applications due to temperature constraints and high cost. To develop a marketable SOFC, suppliers have tended to reduce the operating temperatures by a few hundred degrees. The overall trend for SOFC materials is to reduce their service temperature of electrolyte. Meanwhile, it is...
The effect of additives on anode passivation in electrorefining of copper
, Article Chemical Engineering and Processing: Process Intensification ; Volume 46, Issue 8 , 2007 , Pages 757-763 ; 02552701 (ISSN) ; Yoozbashizadeh, H ; Sadegh Safarzadeh, M ; Sharif University of Technology
2007
Abstract
In copper electrorefining process, some additives are added to the electrolyte to improve the morphology of cathode deposits as well as the quality of products. In the present investigation, the effects of thiourea, glue and chloride ions (as additives) on the passivation of industrial copper anodes under high current densities have been reported. Experiments were conducted at 65 °C; using a synthetic electrolyte containing 40 g/l Cu2+ and 160 g/l H2SO4. Results obtained from chronopotentiometry experiments showed that increasing the concentration of chloride ion leads to increase in passivation time. The results also indicated that from a certain level on, namely 2 ppm, the increase in...
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...
Adsorption of eco-friendly carthamus tinctorius on steel surface in saline solution: a combination of electrochemical and theoretical studies
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 601 , 20 September , 2020 ; Ramazani Saadat Abadi,A ; Mahdavian, M ; Bahlakeh, G ; Haddadi, S. A
Elsevier B.V
2020
Abstract
In this study, the different parts of carthamus tinctorius plant, including petal (SPE), leaf (SLE), and shoot (SSE), have been extracted. Adsorption of the extracts on mild steel in 3.5 wt. % NaCl solution was evaluated employing electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, and electrochemical noise measurements (EN). The field-emission scanning electron microscopy (FE-SEM) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) were employed to appraise the morphology of the samples surface subjected to the test solutions. According to the EIS results, the maximum adsorption efficiency belonged to the solution containing 1 g L−1 of...
Implementation of Ag nanoparticle incorporated WO3 thin film photoanode for hydrogen production
, Article International Journal of Hydrogen Energy ; Volume 38, Issue 5 , 2013 , Pages 2117-2125 ; 03603199 (ISSN) ; Kim, H ; Choi, W ; Moshfegh, A. Z ; Sharif University of Technology
2013
Abstract
WO3 thin film photoanodes containing different concentrations of Ag nanoparticles were synthesized by solegel method. Based on UV-visible spectra, presence of a surface plasmon resonance peak at 470 nm of wavelength indicated formation of silver nanoparticles in the WO3 films. According to atomic force microscopy (AFM) analysis, the highest value for surface roughness and the effective surface ratio was observed for the sample containing 2 mol% of Ag. X-ray diffraction (XRD) patterns revealed that WO 3 nanocrystalline structure was formed in the monoclinic phase with the average size of about 18.2 nm while Ag nanocrystals were determined in cubic phase. X-ray photoelectron spectroscopy (XPS)...
Visible light active Au:TiO2 nanocomposite photoanodes for water splitting: Sol-gel vs. sputtering
, Article Electrochimica Acta ; Volume 56, Issue 3 , January , 2011 , Pages 1150-1158 ; 00134686 (ISSN) ; Sangpour, P ; Moshfegh, A. Z ; Sharif University of Technology
2011
Abstract
In this study, pure TiO2 and Au:TiO2 nanocomposite thin films are both synthesized using sol-gel and RF reactive co-sputtering methods. Physical and photoelectrochemical properties of the thin films deposited by each method are compared. The optical density spectra and scanning electron microscopy images of the Au:TiO2 films reveal formation of gold nanoparticles in the all nanocomposite films synthesized by two methods. Moreover, the optical bandgap energy of the thin films decreases with addition of Au nanoparticles. X-ray photoelectron spectroscopy indicates that the presence of gold in metallic state and the formation of TiO2 is stoichiometric. The photoelectrochemical properties of the...