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Synthesis of sodium tungsten oxide nano-thick plates
, Article Materials Letters ; Volume 82 , September , 2012 , Pages 214-216 ; 0167577X (ISSN) ; Mahdavi, S. M ; Irajizad, A ; Ahadi, K ; Sharif University of Technology
Elsevier
2012
Abstract
In this letter a simple procedure to synthesize sodium tungsten oxide nano-thick plates from WO 3 films has been reported. WO 3 films were grown by pulsed-laser deposition method and then heat treated at temperatures up to 560 °C and times up to 120 min. Slide glass was used as both substrate and sodium source simultaneously. XRD analysis revealed presence of an amorphous structure for as-deposited WO 3 films. On the other hand, XRD showed formation of a monoclinic WO 3 structure with annealing in lower temperatures and a triclinic Na 0.5WO 3.25 structure with annealing at higher temperatures. Intensity of the triclinic phase peaks enhanced drastically by rising annealing temperature and...
Electronic structure and morphological study of BaTiO 3 film grown by pulsed-laser deposition
, Article Materials Letters ; Volume 72 , April , 2012 , Pages 107-109 ; 0167577X (ISSN) ; Mahdavi, S. M ; Nemati, A ; Tabesh, M ; Ranjbar, M ; Sharif University of Technology
Abstract
The morphological characteristics and electronic structure of the BaTiO 3 films grown by pulsed-laser deposition technique have been investigated. AFM and FE-SEM images reveal columnar growth characteristic of these films. Utilizing spectrophotometer, optical band gap of the films were reckoned to be about 3.76 eV. Both dα/dE and PL vs. E plots reveal numerous luminance states in the gap. Despite the presence of many luminance faults in the gap, cations manage to preserve their electronic states
Fabrication of HAp-8YSZ composite layer on Ti/TiO2 nanoporous substrate by EPD/MAO method
, Article Materials Letters ; Volume 65, Issue 23-24 , 2011 , Pages 3421-3423 ; 0167577X (ISSN) ; Moshayedi, Sh ; Ghaffari, S. A ; Rezaei, H. R ; Golestani Fard, F ; Sharif University of Technology
Abstract
Zirconia/Hydroxyapatite composites containing 20-50 wt.% 8YSZ were prepared on Ti/TiO2 substrates by electrophoretic deposition (EPD)/micro-arc oxidation (MAO) process. Titania, as an inner layer, was grown on the Ti plates using MAO treatment in order to form a strong join between substrate and HAp. These composites were produced by EPD in ethanol containing ZrO2/HAp particles at 50, 100 and 150 V in 1 min. Asprepared samples were sintered at 900, 1100 and 1300 °C. HAp, β-TCP, CaZrO3 phases were identified using X-ray diffractometry analysis (XRD). Scanning electron microscopy (SEM) utilized to study the surface morphology indicated a crack free microstructure at 1300 °C
Effects of native and non-native resins on asphaltene deposition and the change of surface topography at different pressures: an experimental investigation
, Article Energy and Fuels ; Volume 29, Issue 9 , July , 2015 , Pages 5487-5494 ; 08870624 (ISSN) ; Zolghadr, A ; Ayatollahi, S ; Sharif University of Technology
American Chemical Society
2015
Abstract
Asphaltene deposition during oil production and transportation causes extensive damage to reservoirs and wellhead equipment. In this study, the effects of native and non-native resins as well as those of their mixtures on the asphaltene deposition process are investigated. A novel pressure, volume, and temperature (PVT) visual cell is used to check the effect of resin on asphaltene deposition at different pressures and reservoir temperatures. Two Iranian crude oil samples with different potentials of asphaltene deposition (low and high) were used in these tests. During depressurizing in the presence of native and non-native resins, the amount of asphaltene deposited was measured. To monitor...
Studies on the catalyst preparation methods and kinetic behavior of supported cobalt catalysts for the complete oxidation of cyclohexane
, Article Reaction Kinetics, Mechanisms and Catalysis ; Volume 114, Issue 2 , Jan , 2015 , Pages 611-628 ; 18785190 (ISSN) ; Khorasheh, F ; Shayegan, J ; Sharif University of Technology
Springer Netherlands
2015
Abstract
Low cost dispersed supported cobalt oxide nanocatalysts on activated carbon (AC) were prepared by two different methods: (1) combined impregnation and deposition–precipitation (IMP-DP) and (2) heterogeneous deposition–precipitation (HDP). XRD, TEM, FESEM, BET and Boehm techniques were used for the characterization of the support and the catalysts. Characterization analyses indicated the negative effect of the wet impregnation method on the IMP-DP technique for the preparation of catalysts for the total oxidation of cyclohexane in air. The catalysts prepared by HDP and IMP-DP methods were found to have significant differences in oxidation activity, morphology, particle size, and shape of...
Comparison of synthesis and purification of carbon nanotubes by thermal chemical vapor deposition on the nickel-based catalysts: NiSio2 and 304-type stainless steel
, Article Journal of Applied Sciences ; Volume 10, Issue 9 , 2010 , Pages 716-723 ; 18125654 (ISSN) ; Jafari, A ; Fekri, S ; Shafikhani, A ; Vesaghi, M ; Behzadi, G ; Sharif University of Technology
2010
Abstract
In this study by Thermal Chemical Vapor Deposition (TCVD) method, the synthesis of carbon nanotubes (CNTs) and temperature affects on the grown CNTs on the NiSio2 catalyst and 304-type stainless steel was investigated. The purification of the grown CNTs on the 304-type stainless steel was also investigated in this study. The synthesis and purification of the samples were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), termogravimetric analysis (TGA) and Raman spectroscopy. Our obtained result by SEM and TEM shows that densities of CNTs growth on the 304-type stainless steel are more than the CNTs growth on the NiSio2 catalyst and both of them have...
One-step fabrication of electrochemically reduced graphene oxide/nickel oxide composite for binder-free supercapacitors
, Article International Journal of Hydrogen Energy ; Volume 41, Issue 39 , 2016 , Pages 17496-17505 ; 03603199 (ISSN) ; Mohammadi, R ; Asadian, E ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
A three-dimensional (3D) graphene/Nickel oxide (ERGO/NiO) composite electrode have been fabricated directly on a Nickel foam substrate via a one-step electrochemical co-deposition in an aqueous solution containing Nickel nitrate and GO. By using this simple and one-step electrochemical deposition, it is possible to produce binder-free composite electrodes with improved electrochemical properties using a low-cost, facile and scalable technique. It is observed from FE-SEM images that graphene oxide sheets affect the electrodeposition of nickel oxide. The optimized ErGO/NiO electrode developed in this work exhibits high charge storage capacity with a specific capacitance of 1715.5 F g−1 at...
Fabrication and surface stochastic analysis of enhanced photoelectrochemical activity of a tuneable MoS2-CdS thin film heterojunction
, Article RSC Advances ; Volume 6, Issue 20 , 2016 , Pages 16711-16719 ; 20462069 (ISSN) ; Ebrahimi, M ; Zhao, M ; Moradlou, O ; Samadi, M ; Bayat, A ; Zhang, H. L ; Moshfegh, A. Z ; Sharif University of Technology
Royal Society of Chemistry
2016
Abstract
A very simple and well-controlled procedure was employed to prepare CdS nanoparticle/few-layer MoS2 nanosheet/Indium tin oxide (ITO) thin film heterostructures. To tune and fabricate the CdS/MoS2(t)/ITO thin films with various surface topographies, first electrophoretic deposition (EPD) was used to deposit MoS2 nanosheets on the ITO substrate under an optimized applied potential difference (8 V) for different deposition times (t) of 30, 60, 120 and 240 s. Then, CdS nanoparticles were deposited via a successive ion layer adsorption and reaction (SILAR) technique. The highest photo-current density of 285 μA cm-2 was measured for the CdS/MoS2(60 s)/ITO sample, which was about 2.3 times higher...
Filtration of aerosol particles by cylindrical fibers within a parallel and staggered array
, Article Microsystem Technologies ; Volume 22, Issue 5 , 2016 , Pages 965-977 ; 09467076 (ISSN) ; Moosavi, A ; Sadrhosseini, H ; Sharif University of Technology
Springer Verlag
2016
Abstract
The World Health Organization (WHO) in 2013 reported that more than seven million unexpected losses every year are credited to air contamination. Because of incredible adaptability and expense viability of fibrous filters, they are broadly used for removing particulates from gasses. The influence of appropriate parameters, e.g., the fiber arrangement, solid volume fraction (SVF or α), fluid flow face velocity (mean inlet velocity), and filter thickness (Ix), on pressure drop and deposition efficiency are researched. Furthermore, to study the effects of variation of the laminar flow regime and fiber’s cross-sectional shape on the deposition of particles, only a single square fiber has been...
Investigation of CeO2 buffer layer effects on the voltage response of YBCO transition-edge bolometers
, Article IEEE Transactions on Applied Superconductivity ; Volume 26, Issue 3 , 2016 ; 10518223 (ISSN) ; Nazifi, R ; Wulff, A. C ; Vesaghi, M. A ; Grivel, J. C ; Fardmanesh, M ; Sharif University of Technology
Abstract
The effect on the thermal parameters of superconducting transition-edge bolometers produced on a single crystalline SrTiO3 (STO) substrate with and without a CeO2 buffer layer was investigated. Metal-organic deposition was used to deposit the 20-nm CeO2 buffer layer, whereas RF magnetron sputtering was applied to fabricate 150-nm-thick superconducting YBa2Cu3O7-δ (YBCO) thin film. The critical transition temperature for both of the YBCO films was 90 K, and the transition width was ∼1.9 K. The bolometers fabricated from these samples were characterized with respect to the voltage phase and amplitude responses, and the results were compared with that of simulations conducted by applying a...
Surface modifications of titanium implants by multilayer bioactive coatings with drug delivery potential: antimicrobial, biological, and drug release studies
, Article JOM ; Volume 68, Issue 4 , 2016 , Pages 1100-1108 ; 10474838 (ISSN) ; Petrova Zustiak, S ; Simchi, A ; Sharif University of Technology
Abstract
Recent strategies to locally deliver antimicrobial agents to combat implant-associated infections—one of the most common complications in orthopedic surgery—are gaining interest. However, achieving a controlled release profile over a desired time frame remains a challenge. In this study, we present an innovative multifactorial approach to combat infections which comprises a multilayer chitosan/bioactive glass/vancomycin nanocomposite coating with an osteoblastic potential and a drug delivery capacity. The bioactive drug-eluting coating was prepared on the surface of titanium foils by a multistep electrophoretic deposition technique. The adopted deposition strategy allowed for a high...
Plasticity in polymeric honeycombs made by photo-polymerization and nozzle based 3D-printing
, Article Polymer Testing ; Volume 63 , 2017 , Pages 163-167 ; 01429418 (ISSN) ; Bagheri, R ; Avila Gray, L ; Altstädt, V ; Drechsler, K ; Sharif University of Technology
Abstract
Study of the plastic deformation in polymeric honeycombs can pave the way for understanding the deformation localization in more complex cellular structures, which have received progressive attention in the past few years. This study compares the strain localization in deforming honeycombs made by two cost-effective 3D-printing technologies. Hexagonal honeycombs and their unit cell models were 3D-printed by both PolyJet™, using a photo-crosslinkable polymer, and fused deposition modeling (FDM) using a thermoplastic material. The state of the art digital image correlation (DIC) technique was employed as the experimental route in order to calculate the strain field during the deformation of...
Fabrication of self-organized precisely tunable plasmonic SERS substrates via glancing angle deposition
, Article Physica Status Solidi (A) Applications and Materials Science ; Volume 214, Issue 9 , 2017 ; 18626300 (ISSN) ; Ualibek, O ; Bulfin, B ; Sugurbekova, G ; Duesberg, G. S ; Shvets, I ; Sharif University of Technology
Abstract
Plasmonic nanostructures offer great enhancement of the Raman signal due to the strong confinement of the electromagnetic field. Thus, they are considered as suitable candidates for surface enhanced Raman spectroscopy (SERS). In this work, we present an alternative fabrication route, called the glancing angle deposition (GLAD), for tunable fabrication of plasmonic self-organized Ag nanoparticle arrays aimed at SERS. Using the GLAD technique, the inter-particle distance within the arrays can be made as small as 1 nm. Moreover, the plasmonic resonance can be precisely tuned over the whole visible range. The GLAD method can be up-scaled; and when a transparent substrate is used, it enables...
Dispersion and deposition of nanoparticles in microchannels with arrays of obstacles
, Article Microfluidics and Nanofluidics ; Volume 21, Issue 4 , 2017 ; 16134982 (ISSN) ; Moosavi, A ; Sadrhosseini, H ; Sharif University of Technology
Springer Verlag
2017
Abstract
Air pollutants are among the hazardous materials for human health. Therefore, many scientists are interested in removing particles from the carrier gas. In this study, flow of air and airborne particles through the virtual multi-fibrous filters that consist of different fiber cross-sectional shapes and arrangements is simulated where particle deposition and filtration performance are studied. Regular and irregular arrangements of fibers with the circular, elliptical, and equilateral triangular cross sections have been considered. Effects of important parameters such as solid volume fraction, internal structure, and filter thickness on particle collection efficiency and pressure drop are...
Facile synthesis of CuO@PbS core/shell nanowire arrays
, Article Materials Letters ; Volume 193 , 2017 , Pages 259-262 ; 0167577X (ISSN) ; Youzbashi, A. A ; Heidari Saani, M ; Rashidi, A ; Kazemzadeh, A ; Kiani, F ; Sharif University of Technology
Abstract
Nanowire arrays of copper oxide were first grown vertically using simple and cost effective thermal oxidation method on a copper foil. Subsequently, in order to deposit and grow PbS nanocyrstalline thin films on CuO NWs by utilizing the chemical bath deposition technique, these arrays were immersed as the substrate in the reaction solution consisting of Pb(NO3)2, (NH2)2CS and NaOH. The final products were characterized in detail by which the formation of uniform, unique arrays of CuO@PbS core–shell NWs was confirmed. Due to the nature of methods employed in synthesis of this hetero structure, the tuning of core and shell size and consequently properties of the novel structure is easily...
New two-dimensional particle-scale model to simulate asphaltene deposition in wellbores and pipelines
, Article Energy and Fuels ; Volume 32, Issue 3 , 2018 , Pages 2661-2672 ; 08870624 (ISSN) ; Joonaki, E ; Taghikhani, V ; Bozorgmehry Boozarjomehry, R ; Chapoy, A ; Tohidi, B ; Sharif University of Technology
American Chemical Society
2018
Abstract
A new two-dimensional dynamic model was developed to simulate asphaltene precipitation, aggregation, and deposition at isothermal and non-isothermal conditions. The perturbed-chain statistical associating fluid theory equation of state was used to model the asphaltene precipitation. Also, novel kinetic models were used to account for the aggregation and deposition of asphaltene particles. The effect of the aggregate size on the rate of aggregation and deposition was studied, and it was concluded that the rate of asphaltene deposition increases, while the concentration of nanoaggregates increases in the well column. The tendency of smaller aggregates to deposit on the surface could be...
Numerical modeling and simulation of drilling cutting transport in horizontal wells
, Article Journal of Petroleum Exploration and Production Technology ; Volume 8, Issue 2 , 2018 , Pages 455-474 ; 21900558 (ISSN) ; Sarafraz, S ; Tabzar, A ; Hemmati, N ; Shadizadeh, S. R ; Sharif University of Technology
Springer Verlag
2018
Abstract
Cutting transport is an important goal in drilling operation especially in horizontal and deviated wells since it can cause problems such as stuck pipe, circulation loss and high torque and drag. To this end, this article focused on the affecting parameters on the cutting transport by computational fluid dynamic (CFD) modeling and real operational data. The effect of drilling fluid and cutting density on the pressure drop, deposit ratio and string stress on the cutting transport has been investigated. A systematic validation study is presented by comparing the simulation results against published experimental database. The results showed that by increasing two times of drilling fluid...
Additive manufacturing of Ti–6Al–4V parts through laser metal deposition (LMD): Process, microstructure, and mechanical properties
, Article Journal of Alloys and Compounds ; Volume 804 , 2019 , Pages 163-191 ; 09258388 (ISSN) ; Colera, X. G ; Mirzaali, M. J ; Sovizi, S ; Bartolomeu, F ; St Weglowski, M. K ; Wits, W. W ; Yap, C. Y ; Ahn, J ; Miranda, G ; Silva, F. S ; Madaah Hosseini, H. R ; Ramakrishna, S ; Zadpoor, A. A ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
As one of the most important additive manufacturing (AM) techniques, laser metal deposition (LMD) has been extensively studied specially during the last few years. Similar to other AM techniques, the quality of LMD parts is highly dependent on the processing parameters that need to be optimized so as to obtain geometrically accurate parts as well as favorable microstructures and, thus, mechanical properties. The present review paper therefore aims to present a critical analysis and overview of the relationship between processing parameters, microstructure, and mechanical properties of LMD components made from the Ti–6Al–4V alloy. Moreover, we discuss the applications of LMD parts in the...
Photovoltaic performance improvement in vacuum-assisted meniscus printed triple-cation mixed-halide perovskite films by surfactant engineering
, Article ACS Applied Energy Materials ; Volume 2, Issue 9 , 2019 , Pages 6209-6217 ; 25740962 (ISSN) ; Abdollah Zadeh, A ; Dehghani, M ; Taghavinia, N ; Sharif University of Technology
American Chemical Society
2019
Abstract
Scalable coating methods have recently emerged as practical alternative deposition techniques to the conventional spin-coating despite their lower yielding power conversion efficiencies (PCEs). The most important barrier acting against the use of scalable deposition methods to get a highly absorbing (>95%) film with controlled morphology in the high crystallinity of perovskite particles is the impossibility of antisolvent dripping during the deposition. Here, we demonstrate the positive role of both the surfactant-engineering and the vacuum-annealing (<100 Pa) process in improving the device performance to overcome this limit. A detailed optimization of the vacuum-assisted meniscus printing...
Composites of reduced graphene oxide/nickel submicrorods for non-enzymatic electrochemical biosensing: application to amperometric glucose detection
, Article Journal of the Electrochemical Society ; Volume 167, Issue 8 , 2020 ; Mazaheri, M ; Sedighian, A ; Ghanbari, H ; Simchi, A ; Sharif University of Technology
Institute of Physics Publishing
2020
Abstract
For the rapid detection of hyperglycemia in human blood, we adopted a facile and two-step electrochemical procedure to prepare nickel/reduced graphene oxide (rGO) hybrid electrodes in the framework of a three-dimensional (3D) nanostructure. High-density and vertically-aligned nickel submicrorods with an average diameter of 155 ± 15 nm and a length of 7 ± 1 μm (an aspect ratio of about 40-50) were prepared by template-mediated electrochemical deposition techniques. Networks of rGO nanosheets between the rod-shaped arrays were formed by the cathodic electrophoretic deposition method. The synergistic effect of nickel morphology (planar and high-density rod-shaped arrays) and graphene oxide...