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Enhancing the formation of tetragonal phase in perovskite nanocrystals using an ultrasound assisted wet chemical method
, Article Ultrasonics Sonochemistry ; Volume 33 , 2016 , Pages 141-149 ; 13504177 (ISSN) ; Ashiri, R ; Sharif University of Technology
Elsevier
2016
Abstract
Synthesis of highly-pure tetragonal perovskite nanocrystals is the key challenge facing the development of new electronic devices. Our results have indicated that ultrasonication is able in enhancing the formation of tetragonal phase in perovskite nanocrystals. In the current research, multicationic oxide perovskite (ATiO3; A: Ba, Sr, Ba0.6Sr0.4) nanopowders are synthesized successfully by a general methodology without a calcination step. The method is able to synthesize high-purity nanoscale ATiO3 (BaTiO3, SrTiO3, Ba0.6Sr0.4TiO3) with tetragonal symmetry at a lower temperature and in a shorter time span in contrast to the literature. To reach an in-depth understanding of the scientific...
Design and Manufactur, Medical Stent at Stainless Steel 316L
, M.Sc. Thesis Sharif University of Technology ; Akbarzadeh, Abbas (Supervisor)
Abstract
Due to increased mortality from Coronary Heart Disease, it is important to work on ways to treat this disease. An effective method of treatment on this disease is the coronary stent implantation. There are nearly two decades passed since implanting the first heart stent. The main objective of this research is design and manufacturing of the medical stents of stainless steel 316 L. Stent materials should have excellent corrosion resistance and biocompatibility. Various materials such as stainless steel 316 L, platinum alloys, niobium alloys, cobalt alloys are used for manufacturing the stents. In this project, at the first stage seam tube was prodected with laser welding of a tube with...
Capacity Optimization of the Pride Engine Assembly Line
,
M.Sc. Thesis
Sharif University of Technology
;
Esharagh Niaye Jahromi, Abdolmajid
(Supervisor)
Abstract
In this project optimization of the assembly line balancing of Pride Motor is considered. The technical specification and limitizations as well as the production process of the product of this line is studied and documented through opc-fpc diagram, and assembly charts. Differential time study procedures are studied and the stop watch approach is selected to calculate the normal time of each operation. Through evaluation of line bottle necks the most important stations are reconsidered and have been pointed out.Considering operations procedure, priorities of the operations in the line, number of operations in each station, and requirements of investments for the changes, a solution for...
Sonochemical Synthesis of SrTiO3 Nanocrystals at Low Temperature
, Article International Journal of Applied Ceramic Technology ; Volume 12, Issue S2 , 2014 , pp. E202-E206 ; Ajami, R ; Moghtada, A ; Sharif University of Technology
2014
Abstract
This work aims to develop an innovative low-temperature sonochemical synthesis pathway for synthesizing the carbonate-free SrTiO3 nanocrystals with tailored morphology. Ultrasonication causes the formation of stoichiometric SrTiO3 nanocrystals and accelerates their formation. Moreover, SrTiO3 nanocrystals are synthesized at low temperature. The methodology described here is simple, fast, cost-effective, and useful for large-scale production purposes
Facile synthesis of NiTiO3 yellow nano-pigments with enhanced solar radiation reflection efficiency by an innovative one-step method at low temperature
,
Article
Dyes and Pigments
;
Volume 123
,
2015
,
Pages 92-99
;
01437208 (ISSN)
; Shahrouzianfar, A
; Ashiri, R
;
Sharif University of Technology
Elsevier Ltd
2015
Abstract
Abstract Inorganic NiTiO3 nano-pigments have received recent attentions as possible candidates for cool pigment materials to be used in building roofs and facades. In this paper, we have attempted to develop an innovative low temperature (50 °C) synthesis pathway for obtaining NiTiO3 nanocrystals based on an ultrasound-assisted wet chemical processing method. The crystallite size, average particle size and band gap are found to be 11 nm, in the range of 10-20 nm and 3.72 eV, respectively. Ultraviolet-visible (UV-vis) reflectance spectra show that NiTiO3 nanoparticles have a high reflection peak at ∼580 nm, which is associated with the brilliant yellow color...
Sonochemical synthesis of SrTiO3 nanocrystals at low temperature
,
Article
International Journal of Applied Ceramic Technology
;
Volume 12, Issue S2
,
2015
,
Pages E202-E206
;
1546542X (ISSN)
; Ajami, R
; Moghtada, A
;
Sharif University of Technology
Blackwell Publishing Ltd
2015
Abstract
This work aims to develop an innovative low-temperature sonochemical synthesis pathway for synthesizing the carbonate-free SrTiO3 nanocrystals with tailored morphology. Ultrasonication causes the formation of stoichiometric SrTiO3 nanocrystals and accelerates their formation. Moreover, SrTiO3 nanocrystals are synthesized at low temperature. The methodology described here is simple, fast, cost-effective, and useful for large-scale production purposes
Facile synthesis of NiTiO3 yellow nano-pigments with enhanced solar radiation reflection efficiency by an innovative one-step method at low temperature
, Article Dyes and Pigments ; Volume 139 , 2017 , Pages 388-396 ; 01437208 (ISSN) ; Shahrouzianfar, A ; Ashiri, R ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
Inorganic NiTiO3 nano-pigments have received recent attentions as possible candidates for cool materials to be used in building roofs and facades. In this paper, we have attempted to develop an innovative low temperature pathway (processed at 50 °C) for obtaining NiTiO3 nanocrystals by an ultrasound-assisted wet chemical processing method. Different characterization techniques such as X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and diffuse reflectance spectroscopy (DRS) were used in order to characterize the size, morphology and optical responses of the obtained NiTiO3...
Low-temperature ultrasound synthesis of nanocrystals CoTiO3 without a calcination step: Effect of ultrasonic waves on formation of the crystal growth mechanism
, Article Advanced Powder Technology ; Volume 28, Issue 4 , 2017 , Pages 1109-1117 ; 09218831 (ISSN) ; Shahrouzianfar, A ; Ashiri, R ; Sharif University of Technology
Elsevier B.V
2017
Abstract
CoTiO3 nanocrystallites with an average diameter of 50 nm were synthesized successfully by the sonochemical method without a calcination step and using C10H16N2O8 (EDTA) as the chelating agent. To reach an in-depth understanding of the scientific basis of the proposed process, an in-detail analysis was carried out for characterization of nanoscale CoTiO3 particles via XRD, FTIR, FE-SEM and UV–vis diffuse reflectance spectroscopy (DRS). The crystallite size, average particle size and band gap are found to be 10.7 nm, in the range of 50 nm and 4.64 eV, respectively. The mechanism and the formation process of CoTiO3 in the sonochemical process were proposed. It was found that nanocrystals were...