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 Paknahad, Pouyan (Author) ; 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 Paknahad, Pouyan (Author) ; 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 Paknahad, P ; 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 CuCo2O4 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) Paknahad, P ; Askari, M ; Ghorbanzadeh, M ; Sharif University of Technology

Springer Verlag 2015

Abstract

CuCo2O4 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 CuCo2O4 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) Paknahad, P ; 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 Paknahad, P ; 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....

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) Paknahad, P ; 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...

Secrecy capacity scaling in large cooperative wireless networks

, Article IEEE Transactions on Information Theory ; Volume 63, Issue 3 , 2017 , Pages 1923-1939 ; 00189448 (ISSN) Mirmohseni, M ; Papadimitratos, P. P ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2017

Abstract

We investigate large wireless networks subject to security constraints. In contrast to point-to-point, interferencelimited communications considered in prior works, we propose active cooperative relaying-based schemes. We consider a network with nl legitimate nodes, ne eavesdroppers, and path loss exponent α ≥ 2. As long as n2e (log(ne))γ = o(nl ), for some positive γ , we show that one can obtain unbounded secure aggregate rate. This means zero-cost secure communication, given fixed total power constraint for the entire network. We achieve this result through: 1) the source using Wyner randomized encoder and a serial (multi-stage) block Markov scheme, to cooperate with the relays and 2) the...

Fast estimation of connectivity in fractured reservoirs using percolation theory

, Article SPE Journal ; Volume 12, Issue 2 , 2007 , Pages 167-178 ; 1086055X (ISSN) Masihi, M ; King, P. R ; Nuratza, P ; Sharif University of Technology

Society of Petroleum Engineers (SPE) 2007

Abstract

Investigating the impact of geological uncertainty (i.e., spatial distribution of fractures) on reservoir performance may aid management decisions. The conventional approach to address this is to build a number of possible reservoir models, upscale them, and then run flow simulations. The problem with this approach is that it is computationally very expensive. In this study, we use another approach based on the permeability contrasts that control the flow, called percolation approach. This assumes that the permeability disorder of a rock can be simplified to either permeable or impermeable. The advantage is that by using some universal laws from percolation theory, the effect of the complex...

A new decoding scheme for errorless codes for overloaded CDMA with active user detection

, Article 2011 18th International Conference on Telecommunications, ICT 2011, Ayia Napa, 8 May 2011 through 11 May 2011 ; 2011 , Pages 201-205 ; 9781457700248 (ISBN) Mousavi, A ; Pad, P ; Delgosha, P ; Marvasti, F ; Sharif University of Technology

2011

Abstract

Recently, a new class of binary codes for overloaded CDMA systems are proposed that not only has the ability of errorless communication but also suitable for detecting active users. These codes are called COWDA. In [1], a Maximum Likelihood (ML) decoder is proposed for this class of codes. Although the proposed scheme for coding/decoding shows impressive performance, the decoder can be significantly improved. In this paper, by assuming practical conditions for the traffic in the system, we suggest and prove an algorithm that increases the performance of the decoder several orders of magnitude (the Bit-Error-Rate (BER) is divided by a factor of about 400 in some E b/N0's). The algorithm...

Estimation of the Effective Permeability of Heterogeneous Porous Media by Using Percolation Concepts

, Article Transport in Porous Media ; Volume 114, Issue 1 , 2016 , Pages 169-199 ; 01693913 (ISSN) Masihi, M ; Gago, P. A ; King, P. R ; Sharif University of Technology

Springer Netherlands 2016

Abstract

In this paper we present new methods to estimate the effective permeability (keff) of heterogeneous porous media with a wide distribution of permeabilities and various underlying structures, using percolation concepts. We first set a threshold permeability (kth) on the permeability density function and use standard algorithms from percolation theory to check whether the high permeable grid blocks (i.e., those with permeability higher than kth) with occupied fraction of “p” first forms a cluster connecting two opposite sides of the system in the direction of the flow (high permeability flow pathway). Then we estimate the effective permeability of the heterogeneous porous media in different...

Percolation-based effective permeability estimation in real heterogeneous porous media

, Article 15th European Conference on the Mathematics of Oil Recovery, 29 August 2016 through 1 September 2016 ; 2016 ; 9462821933 (ISBN); 9789462821934 (ISBN) Masihi, M ; Gago, P ; King, P ; DCSE; Schlumberger; Shell ; Sharif University of Technology

European Association of Geoscientists and Engineers 2016

Abstract

It has long been understood that flow behavior in heterogeneous porous media is largely controlled by the continuity of permeability contrasts. With this in mind, we are looking in new methods for a fast estimation of the effective permeability which concentrates on the properties of the percolating cluster. From percolation concepts we use a threshold permeability value (Kth) by which the gridblocks with the highest permeability values connect two opposite side of the system in the direction of the flow. Those methods can be applied to heterogeneous media of a range of permeabilities distribution and various underlying structures. We use power law relations and weighted power averages that...

Optimization of sputtering parameters for the deposition of low resistivity indium tin oxide thin films

, Article Acta Metallurgica Sinica (English Letters) ; Vol. 27, issue. 2 , Apr , 2014 , p. 324-330 Yasrebi, N ; Bagheri, B ; Yazdanfar, P ; Rashidian, B ; Sasanpour, P ; Sharif University of Technology

2014

Abstract

Indium tin oxide (ITO) thin films have been deposited using RF sputtering technique at different pressures, RF powers, and substrate temperatures. Variations in surface morphology, optical properties, and film resistances were measured and analyzed. It is shown that a very low value of sheet resistance (1.96 ω/sq.) can be achieved with suitable arrangement of the deposition experiments. First, at constant RF power, deposition at different pressure values is done, and the condition for achieving minimum sheet resistance (26.43 ω/sq.) is found. In the next step, different values of RF powers are tried, while keeping the pressure fixed on the previously found minimum point (1-2 Pa). Finally,...

Comparative assessment of gasification based coal power plants with various CO2 capture technologies producing electricity and hydrogen

, Article Energy and Fuels ; Volume 28, Issue 2 , 20 February , 2014 , Pages 1028-1040 ; ISSN: 08870624 Mukherjee, S ; Kumar, P ; Hosseini, A ; Yang, A ; Fennell, P ; Sharif University of Technology

2014

Abstract

Seven different types of gasification-based coal conversion processes for producing mainly electricity and in some cases hydrogen (H2), with and without carbon dioxide (CO2) capture, were compared on a consistent basis through simulation studies. The flowsheet for each process was developed in a chemical process simulation tool "Aspen Plus". The pressure swing adsorption (PSA), physical absorption (Selexol), and chemical looping combustion (CLC) technologies were separately analyzed for processes with CO2 capture. The performances of the above three capture technologies were compared with respect to energetic and exergetic efficiencies, and the level of CO2 emission. The effect of air...

Synthesis of nanosize single-crystal hydroxyapatite via mechanochemical method

, Article Materials Letters ; Volume 63, Issue 5 , 2009 , Pages 543-546 ; 0167577X (ISSN) Nasiri Tabrizi, B ; Honarmandi, P ; Ebrahimi Kahrizsangi, R ; Honarmandi, P ; Sharif University of Technology

2009

Abstract

Single-crystal hydroxyapatite (HAp) nanorods and nanogranules have been synthesized successfully by a mechanochemical process using two distinct experimental procedures. The experimental outcomes are characterized by transmission electron microscopy (TEM), and powder X-ray diffraction (XRD) techniques. In this work, the feasibility of using polymeric milling media to prepare hydroxyapatite nanoparticles is described. The resulting hydroxyapatite powder exhibits an average size of about 20 to 23 nm. Final results indicate that the proposed synthesis strategy provides a facile pathway to obtain single-crystal HAp with high quality and suitable morphology. © 2008 Elsevier B.V. All rights...

Migrating to Cloud-Native architectures using microservices: An experience report

, Article Workshops on CLIoT, WAS4FI, SeaClouds, CloudWay, IDEA, FedCloudNet 2015 held in conjunction with European Conference on Service-Oriented and Cloud Computing, ESOCC 2015, 15 September 2015 through 17 September 2015 ; Volume 567 , 2016 , Pages 201-215 ; 18650929 (ISSN); 9783319333120 (ISBN) Balalaie, A ; Heydarnoori, A ; Jamshidi, P ; Celesti A ; Leitner P ; Sharif University of Technology

Springer Verlag 2016

Abstract

Migration to the cloud has been a popular topic in industry and academia in recent years. Despite many benefits that the cloud presents, such as high availability and scalability, most of the on-premise application architectures are not ready to fully exploit the benefits of this environment, and adapting them to this environment is a non-trivial task. Microservices have appeared recently as novel architectural styles that are native to the cloud. These cloud-native architectures can facilitate migrating on-premise architectures to fully benefit from the cloud environments because non-functional attributes, like scalability, are inherent in this style. The existing approaches on cloud...

Study the effect of connectivity between two wells on secondary recovery efficiency using percolation approach

, Article 15th European Conference on the Mathematics of Oil Recovery, ECMOR 2016, 29 August 2016 through 1 September 2016 ; 2016 ; 9462821933 (ISBN); 9789462821934 (ISBN) Sadeghnejad, S ; Masihi, M ; King, P. R ; Gago, P. A ; Sharif University of Technology

European Association of Geoscientists and Engineers, EAGE 2016

Abstract

Estimating available hydrocarbon to be produced during secondary oil recovery is an ongoing activity in field development. The primary plan is normally scheduled during early stage of field's life through master development plan studies. During this period, due to the lake of certain data, estimation of the field efficiency is usually based on rules of thumb and not detailed field characterization. Hence, there is a great motivation to produce simpler physically-based methodologies. The minimum necessity inputs of percolation approach make it a useful tool for foration performance prediction. This approach enables us to attain a better assessment of the efficiency of secondary recovery...

Modeling of CO2-brine interfacial tension: Application to enhanced oil recovery

, Article Petroleum Science and Technology ; Volume 35, Issue 23 , 2017 , Pages 2179-2186 ; 10916466 (ISSN) Madani, M ; Abbasi, P ; Baghban, A ; Zargar, G ; Abbasi, P ; Sharif University of Technology

2017

Abstract

Development of reliable and accurate models to estimate carbon dioxide–brine interfacial tension (IFT) is necessary, since its experimental measurement is time-consuming and requires expensive experimental apparatus as well as complicated interpretation procedure. In the current study, feed forward artificial neural network is used for estimation of CO2–brine IFT based on data from published literature which consists of a number of carbon dioxide–brine interfacial tension data covering broad ranges of temperature, total salinity, mole fractions of impure components and pressure. Trial-and-error method is utilized to optimize the artificial neural network topology in order to enhance its...

Improved advection algorithm of computational modeling of free surface flow using structured grids

, Article Computer Methods in Applied Mechanics and Engineering ; Volume 195, Issue 7-8 , 2006 , Pages 775-795 ; 00457825 (ISSN) Babaei, R ; Abdollahi, J ; Homayonifar, P ; Varahram, N ; Davami, P ; Sharif University of Technology

2006

Abstract

In the present study a finite difference method has been developed to model the transient fluid flow and heat transfer. A single fluid has been selected for modeling of mold filling and The SOLA-VOF 3D technique was modified to increase the accuracy of simulation of filling phenomena for shape castings. The model was then evaluated with the experimental methods. Refereeing to the experimental and simulation results a good consistency and the accuracy of the suggested model are confirmed. © 2005 Published by Elsevier B.V

Modelling of air pressure effects in casting moulds

, Article Modelling and Simulation in Materials Science and Engineering ; Volume 13, Issue 6 , 2005 , Pages 903-917 ; 09650393 (ISSN) Attar, E ; Homayonifar, P ; Babaei, R ; Asgari, K ; Davami, P ; Sharif University of Technology

2005

Abstract

In the casting process, as a mould is filled with molten metal, air escapes through the vents. Air pressure in the mould cavity has serious effects upon the filling behaviour such as surface profile of the molten metal and filling time. In this project a computational model was developed for calculation of air pressure during the mould filling. A 3D single phase code based on the SOLA-VOF algorithm was used for the prediction of the fluid flow. The ideal gas assumption, conservation of mass equation and Bernoulli law were used for the calculation of air pressure. A new algorithm was developed to interpolate air pressure on the surface cells. The creation of air pressure was correlated with...