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Experimental investigation on the thermal performance of ultra-stable kerosene-based MWCNTs and Graphene nanofluids
, Article International Communications in Heat and Mass Transfer ; Volume 108 , 2019 ; 07351933 (ISSN) ; Rashidi, A ; Koolivand, H ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
A simple chemisorption method was used to graft on the surface of MWCNTs and Graphene nanoparticles to prepare stable kerosene-based MWCNTs and Graphene nanofluids. The prepared nanofluids remained stable for more than five months and no sedimentation was observed. Regarding the effect of temperature on thermo-physical properties, it was observed that although increasing nanoparticle concentration led to an increase in the fluid viscosity, it was negligible enough at lower nanoparticle loading. Moreover, adding nanoparticles to the base fluid did not have any noticeable impact on the fluid density which was negligible even at high concentrations. The thermal conductivity improvement was...
Developing a metamodel based upon the DOE approach for investigating the overall performance of microchannel heat sinks utilizing a variety of internal fins
, Article International Journal of Heat and Mass Transfer ; Volume 149 , 2020 ; Kazemeini, M ; Rashidi, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In this study, the effects of geometry and operating conditions upon the thermal and hydraulic performance of Finned Microchannel Heat Sink (FMCHS) were investigated. Water and aluminum were considered as fluid and solid for the computational domain (30 mm × 0.8 mm × 0.8 mm). The Microchannel (MC) was supposed to have 0.65 mm height with an aspect ratio of 0.5. CFD analysis was applied for the assessments of four-types of micro-fins (i.e., conical, pyramidal, cylindrical and cubical). In order to evaluate the effects of height, diameter, the spacing of fins and Reynolds number on the overall performance of FMCHS, central composite design at five levels was used to generate design points....
Modeling and preparation of activated carbon for methane storage II. neural network modeling and experimental studies of the activated carbon preparation
, Article Energy Conversion and Management ; Volume 49, Issue 9 , September , 2008 , Pages 2478-2482 ; 01968904 (ISSN) ; Soltanieh, M ; Rashidi, A ; Sharif University of Technology
2008
Abstract
This study describes the activated carbon (AC) preparation for methane storage. Due to the need for the introduction of a model, correlating the effective preparation parameters with the characteristic parameters of the activated carbon, a model was developed by neural networks. In a previous study [Namvar-Asl M, Soltanieh M, Rashidi A, Irandoukht A. Modeling and preparation of activated carbon for methane storage: (I) modeling of activated carbon characteristics with neural networks and response surface method. Proceedings of CESEP07, Krakow, Poland; 2007.], the model was designed with the MATLAB toolboxes providing the best response for the correlation of the characteristics parameters and...
An investigation of the oxidative dehydrogenation of propane kinetics over a vanadium-graphene catalyst aiming at minimizing of the COx species
, Article Chemical Engineering Journal ; Vol. 250 , 2014 , Pages 14-24 ; ISSN: 13858947 ; Kazemeini, M ; Khorasheh, F ; Rashidi, A ; Sharif University of Technology
Abstract
Application of the DOE with the ANN in kinetic study of the ODHP was investigated.•The catalyst of vanadium/graphene synthesized through the hydrothermal technique.•The ANN and RSM's simulations were utilized to generate the extra data points.•Power law models and corresponding parameters determined to describe the reactions.•The optimization conducted in order to minimize the COx production. In the current investigation, an application of the design of experiments (DOE) along with the artificial neural networks (ANN) in a kinetic study of oxidative dehydrogenation of propane (ODHP) reaction over a synthesized vanadium-graphene catalyst at 400-500. °C presented aiming at minimizing the CO. x...
Kinetic modeling of oxidative dehydrogenation of propane (ODHP) over a vanadium-graphene catalyst: Application of the DOE and ANN methodologies
, Article Journal of Industrial and Engineering Chemistry ; Vol. 20, issue. 4 , July , 2014 , p. 2236-2247 ; ISSN: 1226086X ; Kazemeini, M ; Khorasheh, F ; Rashidi, A ; Sharif University of Technology
Abstract
In this research the application of design of experiment (DOE) coupled with the artificial neural networks (ANN) in kinetic study of oxidative dehydrogenation of propane (ODHP) over a vanadium-graphene catalyst at 400-500 °C and a method of data collection/fitting for the experiments were presented. The proposed reaction network composed of consecutive and simultaneous reactions with kinetics expressed by simple power law equations involving a total of 20 unknown parameters (10 reaction orders and 5 rate constants each expressed in terms of a pre-exponential factors and activation energies) determined through non-linear regression analysis. Because of the complex nature of the system, neural...
Two-stage fungal leaching of vanadium from uranium ore residue of the leaching stage using statistical experimental design
, Article Annals of Nuclear Energy ; Volume 56 , 2013 , Pages 48-52 ; 03064549 (ISSN) ; Safdari, J ; Roostaazad, R ; Rashidi, A ; Sharif University of Technology
2013
Abstract
In this investigation, bioleaching of vanadium from uranium ore residue of the leaching stage was studied by Aspergillus niger in a two-step process at 30 °C and 150 rpm. The first step was initiated by growth of fungi in the absence of mine waste. Using response surface methodology, three factors were surveyed for fungal growth: initial pH, sucrose concentration and spore population. Also concentrations of oxalic, citric, and gluconic acids were measured as response in this step. During 30 days, maximum productions of these acids were 3265, 11578, and 7988 mg/l, respectively. Initial pH and sucrose concentration were significant factors for oxalic and citric acid production; however, for...
A high performance multi-walled carbon nanotube-supported palladium catalyst in selective hydrogenation of acetylene-ethylene mixtures
, Article Applied Catalysis A: General ; Volume 399, Issue 1-2 , May , 2011 , Pages 184-190 ; 0926860X (ISSN) ; Kazemeini, M ; Rashidi, A. M ; Sharif University of Technology
2011
Abstract
In this research, a palladium nanocatalyst was synthesised over a multi-walled carbon nanotube (MWCNT) support and then applied for selective hydrogenation of acetylene in an ethylene-richflow stream. This material displayed a very promising selectivity toward ethylene production with increasing temperature, and also suppressed oligomer formation during acetylene hydrogenation. New operating conditions for selective hydrogenation of acetylene in an ethylene-richflow were introduced. This nanocatalyst gave a considerably higher yield, as high as 93%, than that previously obtained for ethylene production. It was postulated that the governing mechanism for acetylene hydrogenation over 0.5 wt.%...
Thermal, mechanical and acoustic damping properties of flexible open-cell polyurethane/multi-walled carbon nanotube foams: Effect of surface functionality of nanotubes
, Article Polymer International ; Volume 60, Issue 3 , NOV , 2011 , Pages 475-482 ; 09598103 (ISSN) ; Shojaei, A ; Rashidi, A. M ; Sharif University of Technology
Abstract
This article demonstrates the properties of open-cell flexible polyurethane foams incorporating multi-walled carbon nanotubes. Three different types of highly functionalized nanotubes having carboxyl, hydroxyl and amide functional groups were synthesized. Neat polyurethane foam and three nanocomposite foams filled with 0.1 wt% of treated nanotubes were prepared. It was found that thermal stability, mechanical properties and acoustic damping were improved significantly by incorporation of small amounts of nanotubes. The nanotubes modified with carboxyl groups were found to have much more influence compared to the other two functional groups, possibly due to better interfacial interaction and...
In situ and simultaneous synthesis of a novel graphene-based catalyst for deep hydrodesulfurization of naphtha
, Article Catalysis Letters ; Volume 145, Issue 9 , September , 2015 , Pages 1660-1672 ; 1011372X (ISSN) ; Kazemeini, M ; Rashidi, A ; Bazmi, M ; Sharif University of Technology
Kluwer Academic Publishers
2015
Abstract
In this research, a novel graphene-supported catalyst was prepared through which, a simultaneous chemical exfoliation of graphite and MoS2 powder performed preparing a new composite species and evaluated for the hydrodesulfurization reaction of naphtha and no sulfidation pretreatment was performed upon the catalyst. Also, the influences of the operating parameters such as temperature, and liquid hourly space velocity on HDS conversion evaluated. (Chemical Equation Presented)
Effects of functionalization and catalyst treatments on selective behavior of multi-walled carbon nanotube-supported palladium catalysts in hydrogenation of acetylene
, Article Research on Chemical Intermediates ; Volume 41, Issue 2 , 2015 , Pages 1023-1034 ; 09226168 (ISSN) ; Kazemeini, M ; Rashidi, A. M ; Sharif University of Technology
Kluwer Academic Publishers
2015
Abstract
Two nanocatalysts of palladium over multi-walled carbon nanotubes (MWCNT) were synthesized and their catalytic properties evaluated in selective hydrogenation of acetylene. Different procedures were applied to synthesize catalysts which resulted in two distinct average particle sizes of palladium (Pd) over the MWCNT. The resulting catalysts displayed dissimilar NH3-TPD behaviors as well as different selectivity performances at lower temperatures. While enhancement of the hydrogen transfer mechanism occurred upon the temperature increase, similar behaviors for the aforementioned materials were obtained. Furthermore, it was revealed that the catalytic performance at higher temperatures did not...
Numerical study of forced convective heat transfer of nanofluids: comparison of different approaches
, Article International Communications in Heat and Mass Transfer ; Volume 37, Issue 1 , 2010 , Pages 74-78 ; 07351933 (ISSN) ; Saboohi, Y ; Rashidi, A. M ; Sharif University of Technology
Abstract
Forced convective of a nanofluid that consists of water and Al2O3 in horizontal tubes has been studied numerically. Computed results were validated with existing well established correlation. Two-phase Eulerian model has been implemented for the first time to study such a flow field. A single-phase model and two-phase mixture model formulations were also used for comparison. The comparison of calculated results with experimental values shows that the mixture model is more precise. It is illustrated that the single-phase model and the two-phase Eulerian model underestimates the Nusselt number. Effects of nanoparticles concentration on the thermal parameters are also discussed
Experimental assessment of convective heat transfer coefficient enhancement of nanofluids prepared from high surface area nanoporous graphene
, Article International Communications in Heat and Mass Transfer ; Volume 78 , 2016 , Pages 127-134 ; 07351933 (ISSN) ; Sattari, S ; Rashidi, A. M ; Sharif University of Technology
Elsevier Ltd
Abstract
In this research convective heat transfer coefficient enhancement of nanofluids prepared from high surface area graphene has been investigated in laminar flow in the developing region. The nanofluid has been prepared from nanoporous graphene with high surface area and with concentration of 0.025 to 0.1 wt.%. Deionized water has been used as the base fluid and a type of Ter-Polymer has been utilized as the surfactant. The results indicate that thermal conductivity of nanofluid with concentration of 0.1 wt.% remains quite constant, with only 3.8% enhancement, while convective heat transfer coefficient improves significantly, with 34% enhancement. The behavior of this enhancement related to the...
Graphene based catalysts for deep hydrodesulfurization of naphtha and diesel fuels: A physiochemical study
, Article Fuel ; Volume 165 , 2016 , Pages 468-476 ; 00162361 (ISSN) ; Kazemeini, M ; Rashidi, A ; Bazmi, M ; Sharif University of Technology
Elsevier Ltd
Abstract
In this study, graphene materials have been synthesized with solid camphor (C10H16O) and methane gas as carbon precursors using atmospheric pressure chemical vapor deposition (CVD) technique at a temperature range of 900-1000 °C for a period of 45 min over copper nanoparticles. Influence of the carbon precursors upon the shape, number of layers and yield of the synthesized graphene samples has been investigated. In this venue, the compounds synthesized were functionalized with oxygen groups and impregnated by cobalt and molybdenum active phases. Moreover, the total metal loading and Co/Mo weight ratio of prepared compounds were adjusted to their industrial nominal values of 10% and 0.33,...
Artificial intelligence techniques for modeling and optimization of the HDS process over a new graphene based catalyst
, Article Phosphorus, Sulfur and Silicon and the Related Elements ; Volume 191, Issue 9 , 2016 , Pages 1256-1261 ; 10426507 (ISSN) ; Kazemeini, M ; Rashidi, A ; Tayyebi, S ; Sharif University of Technology
Taylor and Francis Ltd
2016
Abstract
A Co-Mo/graphene oxide (GO) catalyst has been synthesized for the first time for application in a defined hydrodesulfurization (HDS) process to produce sulfur free naphtha. An intelligent model based upon the neural network technique has then been developed to estimate the total sulfur output of this process. Process operating variables include temperature, pressure, LHSV and H2/feed volume ratio. The three-layer, feed-forward neural network developed consists of five neurons in a hidden layer, trained with Levenberg–Marquardt, back-propagation gradient algorithm. The predicted amount of residual total sulfur is in very good agreement with the corresponding experimental values revealing a...
Optimizing parameters affecting synthesis of a novel Co–Mo/GO catalyst in a Naphtha HDS reaction utilizing D-optimal experimental design method
, Article Journal of the Taiwan Institute of Chemical Engineers ; Volume 78 , 2017 , Pages 566-575 ; 18761070 (ISSN) ; Kazemeini, M ; Rashidi, A ; Soltanali, S ; Sharif University of Technology
Abstract
In this research effects of important synthesis parameters upon catalytic performance of a novel graphene based catalyst for an HDS reaction were investigated. The graphene oxide (GO) used as a support was initially prepared through chemical exfoliation of graphite via modified Hummers method. In this venue the impregnation method, promoter/main metallic spices ratio, total metal loading of the active phase and amount of chelating agent were systematically understudied. Thus, GO was impregnated with active metallic phases through the hydrothermal and modified incipient wetness impregnation techniques. In both procedures, 1:2, 1:3 and 1:4 weight ratios of Co/Mo with the percentages of the...
Nickel ion removal from aqueous solution using recyclable zeolitic imidazolate framework-8 (ZIF-8) nano adsorbent: A kinetic and equilibrium study
, Article Desalination and Water Treatment ; Volume 103 , 2018 , Pages 141-151 ; 19443994 (ISSN) ; Rashidi, A ; Borghei, S. M ; Sharif University of Technology
Desalination Publications
2018
Abstract
The adsorption of nickel ions in an aqueous solution system was measured using zeolitic imidazolate framework-8 (ZIF-8) nanoadsorbent. ZIF-8 crystals were synthesized using the hydrothermal method. Nanoadsorbent was characterized by FTIR, XRD, SEM and N2 adsorption analysis. ZIF-8 crystals showed a high surface area of 1303 m2/g and particle size 100–150 nm. The Langmuir and Freundlich isotherms model were used to analyze the data. The sufficiently high R2 value of 0.996 resulted from the Langmuir isotherm model demonstrated the perfect performance of this model. The kinetic data were analyzed using the pseudo-first-order and pseudo-second-order models of types 1–4. Kinetic studies of the...
N-doped CNT nanocatalyst prepared from camphor and urea for gas phase desulfurization: experimental and DFT study
, Article Journal of the Taiwan Institute of Chemical Engineers ; Volume 85 , April , 2018 , Pages 121-131 ; 18761070 (ISSN) ; Banna Motejadded, H ; Rashidi, A ; Hamzehlouyan, T ; Yousefian, Z
Taiwan Institute of Chemical Engineers
2018
Abstract
In the present work, mesoporous nitrogen-doped carbon nanotubes (N-CNTs) were synthesized by using a low-cost and unique set of precursors (camphor and urea). The CVD method at 1000 °C was used with different camphor/urea ratios, and Co-Mo/MgO nanocatalyst was utilized as growth catalyst. Application of mesoporous N-CNTs in selective oxidation of H2S was studied experimentally and N-CNTs interactions with H2S was also investigated using DFT calculations. The as-synthesized N-CNTs were characterized using FTIR, FE-SEM, elemental analysis, X-ray diffraction (XRD), XPS and nitrogen adsorption/desorption. The N-CNT2 sample with urea to camphor ratio (U/C) of 1 showed the highest sulfur yield at...
The oxidative desulfurization process performed upon a model fuel utilizing modified molybdenum based nanocatalysts: Experimental and density functional theory investigations under optimally prepared and operated conditions
, Article Applied Surface Science ; Volume 527 , 2020 ; Kazemeini, M ; Rashidi, A ; Seif, A ; Sharif University of Technology
Elsevier B.V
2020
Abstract
CoMo/reduced graphene oxide (rGO) catalyst was synthesized for the oxidative desulfurization process (ODS) of dibenzothiophene (DBT) in n-decane. Parameters including total metal (Co and Mo) loading, Co/Mo and CA (citric Acid)/Mo molar ratios were investigated toward achieving optimum conditions. The catalysts were characterized by the XRD, ICP, FTIR, Raman Spectroscopy, BET-BJH, NH3-TPD, XPS, and TEM methods. The product sulfur content was measured by the ICP-OES while the product was evaluated using FTIR and 1H NMR analyses. All experimental stages were designed using Design-Expert software. High BET area, acidity, uniform particle size, and Co-promoter played key roles in this...
Modeling and preparation of activated carbon for methane storage I. modeling of activated carbon characteristics with neural networks and response surface method
, Article Energy Conversion and Management ; Volume 49, Issue 9 , September , 2008 , Pages 2471-2477 ; 01968904 (ISSN) ; Soltanieh, M ; Rashidi, A ; Irandoukht, A ; Sharif University of Technology
2008
Abstract
Numerous methods have been proposed previously to describe the characterization of porous materials; however, no well-developed theory is still available. Three different modeling methods were employed in this study to explore the relationship between the characterization parameters of activated carbon (AC) and its methane uptake. The first and the second methods were based on the Radial Basis Function (R.B.F) neural networks. At the first R.B.F. modeling, the neural networks algorithm was designed using the Gaussian function. The collected data for modeling were divided into two parts; (i) the data used for training the network and (ii) the data used for testing the predicted network. At...
Design, manufacture and application of a microreactor for the decomposition of ethyl mercaptan on an H-ZSM-5 catalyst
, Article Journal of Cleaner Production ; Volume 292 , 2021 ; 09596526 (ISSN) ; Kazemeini, M ; Mohammadi, A ; Rashidi, A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Catalytic decomposition of the ethyl mercaptan over an H-ZSM-5 zeolite in a newly designed microreactor was undertaken in this study. A numerically developed distributor possessing superior flow distribution was amended to 24 parallel microchannels with 64 mm length, 700 μm width, and 600 μm depth. Ethyl mercaptan complete conversion required 350 °C through the developed microreactor while in a conventional fixed-bed-reactor 400 °C was needed. Higher selectivity towards the main products of this decomposition (hydrogen sulfide and ethylene) were observed in this microreactor in comparison to that of a fixed-bed-reactor. In addition, lower selectivity towards formation of byproducts was...