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    Kinetic measurements for pseudomonas aeruginosa mr01 during biosurfactant production in two-phase system and developing a double-exponential model for viable cell profile

    , Article World Applied Sciences Journal ; Volume 22, Issue 6 , 2013 , Pages 809-816 ; 18184952 (ISSN) Bagheri Lotfabad, T ; Tayyebi, S ; Roostaazad, R ; Sharif University of Technology
    Biosurfactants are microbial substances which influence interfacial tension. The kinetic study was carried out for Pseudomonas aeruginosa MR01 during biosurfactant production in a two-phase liquid-liquid batch fermentation system. The maximum rhamnolipid concentration (Pmax) and the yield of biosurfactant per 1 biomass (YP/X) in a 5-L bioreactor containing soybean oil medium were found to be approximately 20.9 g.L and 3.1 g.g-1, respectively. Previously reported kinetic models in aqueous systems, three-parameter Gompertz, 2 Luedeking-Piret and Mercier equations, demonstrated adequate goodness-of-fit (r >0.9) to kinetic data recorded for biomass growth, nitrate consumption and rhamnolipid... 

    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) Hajjar, Z ; Kazemeini, M ; Rashidi, A ; Tayyebi, S ; Sharif University of Technology
    Taylor and Francis Ltd  2016
    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... 

    Desulfurization of high sulfur petroleum coke by molten caustic leaching

    , Article Egyptian Journal of Petroleum ; Volume 28, Issue 2 , 2019 , Pages 225-231 ; 11100621 (ISSN) Askari, H ; Khorasheh, F ; Soltanali, S ; Tayyebi, S ; Sharif University of Technology
    Egyptian Petroleum Research Institute  2019
    Desulfurization by molten caustic leaching (MCL) at 400–500 °C has been investigated in order to reduce the sulfur content of petroleum coke. Effective parameters on desulfurization of petroleum coke, other than temperature, include alkali to feed (petroleum coke) mass ratio, time and mesh size in the ranges of 0.5–1.5, 1–3 h and 200–600 µm, respectively. In this work, petroleum coke desulfurization conditions using solid KOH have been studied. Maximum petroleum coke desulfurization by MCL method has been obtained by Taguchi L9 design using alkali to feed mass ratio of 1, temperature of 600 °C, time of 2 h and mesh size of 200 µm. The changes in the main groups on the coke surface have been... 

    Management of soybean oil refinery wastes through recycling them for producing biosurfactant using Pseudomonas aeruginosa MR01

    , Article World Journal of Microbiology and Biotechnology ; Volume 29, Issue 6 , June , 2013 , Pages 1039-1047 ; 09593993 (ISSN) Partovi, M ; Lotfabad, T. B ; Roostaazad, R ; Bahmaei, M ; Tayyebi, S ; Sharif University of Technology
    Biosurfactant production through a fermentation process involving the biodegradation of soybean oil refining wastes was studied. Pseudomonas aeruginosa MR01 was able to produce extracellular biosurfactant when it was cultured in three soybean oil refinement wastes; acid oil, deodorizer distillate and soapstock, at different carbon to nitrogen ratios. Subsequent fermentation kinetics in the three types of waste culture were also investigated and compared with kinetic behavior in soybean oil medium. Biodegradation of wastes, biosurfactant production, biomass growth, nitrate consumption and the number of colony forming units were detected in four proposed media, at specified time intervals.... 

    A new insight into implementing Mamdani fuzzy inference system for dynamic process modeling: Application on flash separator fuzzy dynamic modeling

    , Article Engineering Applications of Artificial Intelligence ; Volume 90 , 2020 Eghbal Ahmadi, M. H ; Royaee, S. J ; Tayyebi, S ; Bozorgmehry Boozarjomehry, R ; Sharif University of Technology
    Elsevier Ltd  2020
    In this work, a novel approach to model the dynamic behavior of the flash separation process (as a main building block of non-reacting stage-wise operations) based on Mamdani Fuzzy Inference Systems is proposed. This model surmounts the need to solve various types of mathematical equations governing the system and does not require thermodynamic properties which are either not available or computationally demanding. Hence it can be easily used in dynamic simulation of multi-phase flow in distributed systems. In the proposed approach the overall model is broken into several simple sub-models based on intuitive analysis of an expert. Moreover, a new fuzzy concept, named “Linguistic Composition...