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Application of Sol-Gel Technique to Synthesis of (Cu,Co)3O4 Spinel on Ferritic Stainless Steel used for Solid Oxide Fuel Cell Interconnects
, M.Sc. Thesis Sharif University of Technology ; Askari, Masoud (Supervisor)
Abstract
Due to recent progresses in lowering the temperature of SOFC, using metallic interconnects instead of ceramic interconnects was possible. Among the alloys used for interconnects, ferritic stainless steels (FSS) due to thermal expansion coefficient compatible with other cell components and cheap fabrication, have become the most widely used material for interconnects. Because of improvement of oxidation resistance of these FSSs, many studies have been made on coating of oxides on FSSs and results show that the spinel oxides have the best performance. In this study, the CuCo2O4 performance as coating in SOFC's interconnects was investigated. Coating process used was sol-gel dip coating and raw...
“Cold Briquetted Iron and Carbon (CBIC)”, Investigation of Oxidation Behavior in Environmental Conditions and Steelmaking Performance
,
Ph.D. Dissertation
Sharif University of Technology
;
Askari, Masoud
(Supervisor)
Abstract
Cold Briquetted Iron and Carbon (CBIC) is a new product in Direct Reduced Iron (DRI) family that aims to produce a reliable product from Cold Direct Reduced Iron (CDRI) with the ability of low risk, high efficient storage and handling. In this study, a comprehensive investigation was carried out on the effects of environmental condition on physical and chemical properties of CBIC, CDRI and Hot Briquetted Iron (HBI) in the first step and then, the steelmaking performance of this new product was compared to the other DRI products in the second step. The changes of microstructure, specific surface area, metallization degree and mechanical strength of different products with time in dry and...
Application of sol-gel technique to synthesis of copper-cobalt spinel on the ferritic stainless steel used for solid oxide fuel cell interconnects
, Article Journal of Power Sources ; Vol. 266, issue , 2014 , pp. 79-87 ; ISSN: 03787753 ; Askari, M ; Ghorbanzadeh, M ; Sharif University of Technology
2014
Abstract
The conductive CuCo2O4 spinel coating is applied on the surface of the AISI 430 ferritic stainless steel by the dip-coating sol-gel process and it is evaluated in terms of the microstructure, oxidation resistance and electrical conductivity. The results show that the CuCO2O 4 coating forms a double-layer scale consisting of a Cr, Fe-rich subscale and Cu-Co spinel top layer after 500 h in air at 800 °C. This scale is protective, acts as an effective barrier against Cr migration into the outer oxide layer and alleviates the cathode Cr-poisoning. The oxidation resistance is significantly enhanced by the protective coating with a parabolic rate constant of 5.8 × 10-13 gr2 cm-4 s -1, meanwhile...
Characterization of nanocrystalline CuCo2 O4 spinel prepared by sol–gel technique applicable to the SOFC interconnect coating
,
Article
Applied Physics A: Materials Science and Processing
;
Volume 119, Issue 2
,
May
,
2015
,
Pages 727-734
;
09478396 (ISSN)
; Askari, M
; Ghorbanzadeh, M
;
Sharif University of Technology
Springer Verlag
2015
Abstract
CuCo2 O4 spinel nanopowders were synthesized by sol–gel method. The optimal values of pH and molar ratio of citric acid to metal ions (RC), and the influence of the calcination temperature and time were investigated. As-prepared materials were characterized by XRD, TGA, DSC, FE-SEM and electrical and coefficient of thermal expansion (CTE) measurements. It was found that pH = 4.5 and RC = 1 are the optimum conditions to produce pure CuCo2 O4 nanopowders. The electrical conductivity was increased remarkably from 15.2 to 27.5 S cm−1 with an increase in temperature from 500 to 800 °C. Over the temperature range of 25–800 °C, the CTE of...
Cold-Briquetted iron and carbon (CBIC): investigation of the influence of environmental condition on its chemical and physical properties
, Article Journal of Sustainable Metallurgy ; Volume 5, Issue 4 , 2019 , Pages 497-509 ; 21993823 (ISSN) ; Askari, M ; Shahahmadi, S. A ; Sharif University of Technology
Springer
2019
Abstract
In this study, a comprehensive investigation was carried out on the effects of environmental condition on physical and chemical properties of Cold-Briquetted Iron and Carbon (CBIC), Cold Direct Reduced Iron (CDRI), and Hot-Briquetted Iron (HBI). The results showed that cold briquetting of CDRI decreases its specific surface area by 51%, which has a significant effect on its oxidation resistance and mechanical strength. Microscopic observations revealed that the oxidation products are formed in near-surface porosities during aging, which protects the fresh material underneath from environmental oxidants, resulting in retarding further oxidation. The oxidation behavior of the samples showed...
Cold-Briquetted Iron and Carbon (CBIC), investigation of steelmaking behavior
, Article Journal of Materials Research and Technology ; Volume 9, Issue 3 , 2020 , Pages 6655-6664 ; Askari, M ; Shahahmadi, S. A ; Sharif University of Technology
Elsevier Editora Ltda
2020
Abstract
In the present paper, the effects of charging of Cold-Briquetted Iron and Carbon (CBIC) into the electric furnace on the steelmaking operating parameters was investigated and compared to the performance of Cold Direct Reduced Iron (CDRI) and Hot-Briquetted Iron (HBI) as the other products of Direct Reduced Iron (DRI) family. The efficiency of the carbon charged through CBIC compared to free-charged carbon into the steelmaking furnace was also evaluated. The results revealed that although the energy consumption of CDRI is somewhat lower than CBIC, the Fe yield content of CBIC is higher and its tap time is lower than CDRI which may improve the productivity of industrial steelmaking plant....
An improved macro-model for simulation of single electron transistor (SET) using HSPICE
, Article TIC-STH'09: 2009 IEEE Toronto International Conference - Science and Technology for Humanity, 26 September 2009 through 27 September 2009, Toronto, ON ; 2009 , Pages 1000-1004 ; 9781424438785 (ISBN) ; Dousti, M ; Pouyan, M ; Faez, R ; Sharif University of Technology
2009
Abstract
To get a more accurate model for simulation of single electron transistors (SETs), we have proposed a new macromodel that includes the ability of electron tunneling time calculation. In our proposed model, we have modified the previous models and applied some basic corrections to their formulas. In addition, we have added a switched capacitor circuit, as a quantizer, to calculate the electron tunneling time. We used HSPICE for high-speed simulation and observed that the simulation results obtained from our model matched more closely with that of SIMON 2.0. We also could evaluate the time of electron tunneling through the barrier by using the quantizer. Clearly, our macro-model gives more...
A New SPICE macro-model for the simulation of single electron circuits
, Article Journal of the Korean Physical Society ; Volume 56, Issue 4 , 2010 , Pages 1202-1207 ; 03744884 (ISSN) ; Dousti, M ; Pouyan, M ; Faez, R ; Sharif University of Technology
2010
Abstract
To get a more accurate model for the simulation of single electron transistors (SETs), we propose a new macro-model that includes an electron tunneling time calculation. In our proposed model, we have modified the previous models and have applied some basic corrections to the formulas. In addition, we have added a switched capacitor circuit, as a quantizer, to calculate the electron tunneling time. We used HSPICE for a high-speed simulation and observed that the simulation results obtained from our model match more closely with that of SIMON 2.0. We also could evaluate the time of electron tunneling through the barrier by using the quantizer. Clearly, our macro-model gives more accurate...
Improving the electrochemical performance of lithium-rich cathode materials by vanadium and titanium co-doping using solution combustion synthesis
, Article Journal of Electrochemical Energy Conversion and Storage ; Volume 20, Issue 1 , 2023 ; 23816872 (ISSN) ; Abasi, A. A ; Glenn, M ; Ghorbanzadeh, M ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2023
Abstract
A lithium-rich layered oxide cathode material (Li1.2[Mn0.54Ni0.13Co0.13]O2) was synthesized using solution combustion synthesis, and the electrochemical effects of co-doping with vanadium and titanium were studied. Materials analysis showed that layered oxides with an α-NaFeO2structure, spherical morphology, and particle size distribution between 0.4 and 1 μm were synthesized. Electrochemical experiments (charge-discharge tests) also indicated that the presence of vanadium in the cathode structure increases its specific capacity to 257.6 mAh/g and improves rate capability and cyclic performance. Increasing the amount of titanium in the cathode improves cyclability; however, it also decreases...
A novel fuzzy genetic annealing classification approach
, Article EMS 2009 - UKSim 3rd European Modelling Symposium on Computer Modelling and Simulation, 25 November 2009 through 27 November 2009, Athens ; 2009 , Pages 87-91 ; 9780769538860 (ISBN) ; Mohamadi, H ; Saniee Abadeh, M ; Foroughifar, A ; Sharif University of Technology
2009
Abstract
In this paper, a novel classification approach is presented. This approach uses fuzzy if-then rules for classification task and employs a hybrid optimization method to improve the accuracy and comprehensibility of obtained outcome. The mentioned optimization method has been formulated by simulated annealing and genetic algorithm. In fact, the genetic operators have been used as perturb functions at the core of simulated annealing heuristic. Results of proposed approach have been compared with several well-known methods such as Naïve Bayes, Support Vector Machine, Decision Tree, k-NN, and GBML, and show that our method performs the classification task as well as other famous algorithms. ©...
Misuse detection via a novel hybrid system
, Article EMS 2009 - UKSim 3rd European Modelling Symposium on Computer Modelling and Simulation, 25 November 2009 through 27 November 2009, Athens ; 2009 , Pages 11-16 ; 9780769538860 (ISBN) ; Abadeh, M. S ; Momenzadeh, A ; Pouyan, M. B ; Sharif University of Technology
2009
Abstract
Intrusion detection systems (IDS) are tools located inside computer networks that analyze the network traffics. In this paper, a novel fuzzy-evolutionary system is presented to effectively detect the intrusion in computer networks. This system utilizes a hybridization of simulated annealing heuristic and tabu search algorithm to improve the accuracy of fuzzy if-then rules as intrusion detectors. Each of these algorithms has its advantageous and disadvantageous. Using the hybrid model of both algorithms, the proposed system employs the good features of them to improve the accuracy of obtained rules. Evaluation of the proposed system is done on the KDDCup99 Dataset which has information about...
The Effect of Type, Size and Morphology of Nanoparticles on the Hydrodynamics of Rising Bubble Motion
, M.Sc. Thesis Sharif University of Technology ; Bastani, Dariush (Supervisor) ; Feizi, Pouyan (Co-Supervisor)
Abstract
The motion of gas bubbles in the bulk of a fluid can be one of the most widely used industrial phenomena. Various factors such as the size and shape of the bubbles, the physical properties of the liquid phase such as density and viscosity, method of gas injection, the presence of impurities, etc. affect this phenomenon. Some of the most important industrial processes that include the motion of bubbles in the liquid phase bulk are gas adsorption, distillation and froth flotation. According to the results of previous studies, the hydrodynamics of bubble motion in the bulk of a liquid fluid depends on the presence of impurities such as surfactants, proteins and colloidal particles. In many...