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rabbani-mehr--alireza
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Multiple-Model Predictive Control for a Fed-Batch Bioreactor of Ethanol Production
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
Bioethanol is an alcohol that is produced by microbial fermentation from carbohydrates produced in sugar-containing plants such as corn, sugarcane, or lignocellulosic biomass. Bioethanol is mostly used as an additive to gasoline. Cars can run on a 15% blend of bioethanol and gasoline and need to be modified to use pure bioethanol. Ethanol in vehicles is beneficial for the environment Because ethanol pollutants are cleaner than greenhouse gases. Ethanol is also used to produce ethyl acetate, which is a widely used solvent in the printing and packaging industries. In this research, fed-batch bioethanol reactor was investigated. First, the modeling of the bioreactor was done and the behavior of...
An automated simple algorithm for realistic pore network extraction from micro-tomography images
, Article Journal of Petroleum Science and Engineering ; Vol. 123, issue , 2014 , pp. 164-171 ; ISSN: 09204105 ; Jamshidi, S ; Salehi, S
2014
Abstract
Using 3-D scanned data to analyze and extract pore network plays a vital role in investigation of porous media's characteristics. In this paper, a new simple method is developed to detect pores and throats for analyzing the connectivity and permeability of the network. This automated method utilizes some of the common and well-known image processing functions which are widely accessible by researchers and this has led to an easy algorithm implementation. In this method, after polishing and quality control of images, using city-block distance function and watershed segmentation algorithm, pores and throats are detected and 3-D network is produced. This method can also be applied on 2-D images...
Specific surface and porosity relationship for sandstones for prediction of permeability
, Article International Journal of Rock Mechanics and Mining Sciences ; Vol. 71, issue , October , 2014 , p. 25-32 ; Jamshidi, S ; Sharif University of Technology
2014
Abstract
Porosity and specific surface are two prominent factors in describing the hydraulic properties of porous media. Determination of these two important parameters leads to identify the capability of porous media to conduct the fluids. In the present study, a new relationship between porosity and specific surface of sandstones has been developed. Micro-CT data from 10 types of sandstones has been utilized in order to present a porosity-specific surface correlation. This correlation also contains the average grain radius of each rock obtained by image processing algorithms. Finally, the correlation is tested on the provided data to evaluate its precision. The simplicity and applicability of the...
Probable thermal effects of plasma impulse action on reservoirs
, Article Saint Petersburg 2012 - Geosciences: Making the Most of the Earth's Resources, 2 April 2012 through 5 April 2012 ; April , 2012 ; Amani, S ; Sharif University of Technology
European Association of Geoscientists and Engineers, EAGE
2012
Abstract
Plasma impulse technology (PIT) is one of the most innovative methods among the oil recovery enhancement (EOR) jobs. Although the low cost and persistent effects of this method has attracted researchers attentions to its self, the governing mechanisms of reservoir remediation in this method are still shrouded in mystery. This study presents a brief discussion on probable thermal mechanisms which govern the interaction between reservoir formation and plasma impulse jet. Minerals dissociation, opening the fused pathway and organic deposits melting seem to be of the most important thermal effects
Probable pressure-based effects of plasma action on reservoirs
, Article Saint Petersburg 2012 - Geosciences: Making the Most of the Earth's Resources, 2 April 2012 through 5 April 2012 ; April , 2012 ; Amani, S ; Sharif University of Technology
European Association of Geoscientists and Engineers, EAGE
2012
Abstract
The applicability of Plasma Impulse Technology (PIT) in the enhancement of oil recovery has been proved in recent years. The priority of this environmental friendly treatment has been proved by the Russian operators which has applied this technology on many production and injection wells. This study presents a brief discussion on probable pressure based mechanisms which govern the interaction between reservoir formation and plasma impulse jet. High pressure of the ejected plasma may cause formation fracturing, damage removal due to pressure shocks and reservoir fluid resonance
Comparing three image processing algorithms to estimate the grain-size distribution of porous rocks from binary 2D images and sensitivity analysis of the grain overlapping degree
, Article Special Topics and Reviews in Porous Media ; Volume 6, Issue 1 , 2015 , Pages 71-89 ; 21514798 (ISSN) ; Ayatollahi, S ; Sharif University of Technology
Begell House Inc
2015
Abstract
The grain-size distribution (GSD) of porous rocks is important in order to better understand their hydrodynamic behavior. Clear and precise GSD data can be used to computationally reconstruct rock structure for further analysis. In this study, three main algorithms for image analysis have been examined to estimate the GSD of clastic rocks. The main challenge in GSD determination from images is in detecting overlapping grains and measuring their size separately. In this study, three previously developed image processing algorithms are implemented on two-dimensional (2D) binary images of rocks in order to compare the obtained GSD from each of the methods, i.e., the mean intercept length...
Dynamic modeling of the formation damage and mud cake deposition using filtration theories coupled with SEM image processing
, Article Journal of Natural Gas Science and Engineering ; Volume 42 , 2017 , Pages 157-168 ; 18755100 (ISSN) ; Salehi, S ; Sharif University of Technology
Elsevier B.V
2017
Abstract
In the present paper, a dynamic modeling is presented for deposition of the mud solid particles over and through the porous sandstones during permeability plugging experiments. Scanning electron microscopy (SEM) coupled with image processing are utilized to find the porosity and pore size distribution of the mud cake. The structure of the porous rock as well as the mud cake are modeled via bundle of the curved tubes approach and deposition probability of the solid particles has been taken into the account through filtration theories. Four different sandstones in addition to four mud samples were utilized to measure and predict the volume of the expelled fluid during the 30 min of filtration...
Modification of carbohydrate polymers via grafting in air. 1. Ceric-Induced synthesis of starch-g-polyacrylonitrile in presence and absence of oxygen [electronic resource]
, Article Starch - Starke ; Volume 54, Issue 3-4, pages 140–147, April 2002 ; Zohurian Mehr, Mohammad J
Abstract
Monomer grafting, a unique technique for polysaccharide modification, is always performed under inert (e.g., N2) atmosphere. This work is the first report related to evaluating the possibility and efficiency of the grafting of acrylonitrile (AN) onto starch in presence of oxygen. Thus, corn starch (in both granular and gelatinized states) as well as soluble starch were grafted by AN using a ceric-carbohydrate redox initiating system. Graft copolymerizations were performed under nitrogen, air, and oxygen atmospheres at similar conditions. Grafting occurrence was verified using chemical and spectral proofs. The polymerization mechanism and kinetics were investigated by recording the...
Modification of carbohydrate polymers via grafting in Air. 2. Ceric-Initiated graft copolymerization of acrylonitrile onto natural and modified polysaccharides [electronic resource]
, Article Starch - Stärke ; Volume 54, Issue 10, pages 482–488, October 2002 ; Zohuriaan-Mehr, Mohammad J
Abstract
Acrylonitrile (AN) was grafted onto various natural and modified polysaccharides (i.e., gum arabic, gum tragacanth, xanthan gum, sodium alginate, chitosan, sodium carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose) by using ceric-carbohydrate redox initiating system. After overcoming practical problems, mainly from the high viscosity of the aqueous solutions of the different substrates, the graft copolymerization reactions were run either in air or in N2 atmosphere under similar conditions. Grafting was confirmed using chemical and spectral (FTIR) proofs. The reactions were kinetically investigated using semi-empirical expressions and time-temperature profiles. An anomalous...
The Relationship between Employees’ Trust in Their Managers and Performance Management Effectiveness
, M.Sc. Thesis Sharif University of Technology ; Alavi, Babak (Supervisor)
Abstract
Several studies in the field of performance management have paid attention to the effect of systemic and instrumental factors on the effectiveness of performance management system. However, the impact of communication and relational factors has received less attention. Furthermore, it seems that similar approach has been used in organizations for considering systemic factors in designing performance management systems rather than human factors. The goal of this research was to study the relationship between employees' trust in their manager as an relational variable with the effectiveness of performance management system and to compare this relationship with the relationship between the...
A new comprehensive framework for ranking accepted orders and supplierselection in make-to-order environments
, Article 2009 International Conference on Computers and Industrial Engineering, CIE 2009, 6 July 2009 through 9 July 2009 ; 2009 , Pages 919-924 ; 9781424441365 (ISBN) ; Ahmadi, G ; Kian, R ; Sharif University of Technology
2009
Abstract
This paper presents a new decision making framework for supplier selectionin a make-to-order-system (MTO) while establishing an information loop between"sale"and"purchasing" functions which play important rolesin successful satisfying of customers. The order entry stage outputs, includingaccepted orders' requirements and their priorities are reflected into thesupplier selection phase; and in return, the outputs of the supplier selectionmodel are fed back into the sale department to revise the orders attributesaccording to the system's supplying capabilities. A ranking procedure usingFuzzy data-envelopment-analysis (DEA) and multi attribute utility model (i.e.similarity to ideal solution...
An efficient algorithm for solving bi-objective fuzzy job-shop scheduling problems by genetic algorithms and data mining
, Article Amirkabir (Journal of Science and Technology) ; Volume 15, Issue 58 D , 2004 , Pages 570-591 ; 10150951 (ISSN) ; Moghaddam, R. T ; Ranjbar, M ; Sharif University of Technology
2004
Abstract
This paper presents a meta-heuristic algorithm for solving bi-objective fuzzy job shop scheduling problems. These objectives are to minimize the makespan and minimize the early and late penalty. Processing time and due date are considered as fuzzy triangular numbers. This paper also introduces a novel use of data mining algorithm for solving of combinatorial optimization problems. The proposed algorithm combines genetic algorithms and an attribute-oriented induction algorithm, which is much quicker than previous methods providing the optimal solution. By considering the structure of proposed algorithm, the whole feasible solutions of a special job shop-scheduling problem are considered as a...
Temporal Congestion Games
, M.Sc. Thesis Sharif University of Technology ; Ghodsi, Mohammad (Supervisor)
Abstract
We consider a special class of Congestion Games enhanced with a notion of time.Network Routing problems, such as road traffic networks, computer neworks, and evacuation problems are some applications of this class of games. Two subclasses of these games, namely atomic and non-atomic is considered in this article, both of them introduced in 2009. Some of the existing results are Nash equilibria existence proof for “single-source single-sink” case, and a mechanism for improving price of anarchy in the non-atomic subclass. There are also some results in the atomic subclass of this game.We extend both models of atomic and non-atomic subclasses to “multi-source,multi-sink” configurations. We call...
Modified CMC: part 1- optimized synthesis of carboxymethylcellulose-g-polyacrylonitrile [electronic resource]
, Article Iranian Polymer Journal ; Vol. 14, No 2, 131-138, 2005 ; Pourjavadi, A ; Sadeghi, M
Abstract
As the first part of a continued research on conversion of carboxymethyl cellulosesodium salt (CMC) to useful biopolymer-based materials, large numbers of cyanide functional groups were introduced onto CMC by grafting with polyacrylonitrile (PAN). The graft copolymerization reactions were carried out under nitrogen atmosphere using ceric ammonium nitrate (CAN) as an initiator. Evidence of grafting was obtained by comparing FTIR spectra of CMC and the graft copolymer as well as solubility characteristics of the products. The synthetic conditions were systematically optimized through studying the effective factors including temperature and concentrations of initiator, acrylonitrile monomer,...
New polysaccharide-g-polyacrylonitrile copolymers: synthesis and thermal characterization [electronic resource]
, Article Polymers for Advanced Technologies ; Volume 14, Issue 7, pages 508–516, July 2003 ; Pourjavadi, Ali ; Sharif University of Technology
Abstract
Various natural and modified polysaccharides (i.e. arabic gum, tragacanth gum, xanthan gum, sodium alginate, chitosan, sodium carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose) were modified using ceric-initiated graft polymerization of acrylonitrile under inert atmosphere. Grafting was confirmed using spectral (FT-IR) proofs. The grafting parameters were determined by conventional methods. Thermal characteristics of the homopolymer-free copolymers were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) under nitrogen atmosphere. The major thermal transitions as well as the activation energy of the major decomposition stages were...
Modified Chitosan. 2. H-chitoPAN, a novel pH-responsive superabsorbent hydrogel [electronic resource]
, Article Journal of Applied Polymer Science ; Volume 90, Issue 11, pages 3115–3121, 9 December 2003 ; Mahdavinia, G. R ; Zohuriaan-Mehr, M. J
Abstract
Chitosan was modified with polyacrylonitrile (PAN) through ceric-initiated graft copolymerization. The chitosan-g-PAN product was saponified using sodium hydroxide aqueous solution to prepare a novel superabsorbent hydrogel, H-chitoPAN. Duration of completing the saponification reaction as well as the water absorbency capacity of the hydrogel was decreased with increasing the alkaline concentration. Either chitosan-g-PAN or H-chitoPAN was characterized by FTIR spectroscopy and DSC, TGA, and DTG thermal methods. According to FTIR, all the nitrile groups were converted to carboxylate and carboxamide groups. Both modified chitosans exhibited enhanced thermal stability over chitosan. The...
A second-order advantage achieved with the aid of gold nanoparticle catalytic activity. Determination of nitrophenol isomers in binary mixtures
, Article Analytical Methods ; Vol. 6, issue. 9 , Feb , 2014 , pp. 3056-3064 ; ISSN: 17599660 ; Abdollahi, H ; Hormozi-Nezhad, M. R ; Sharif University of Technology
2014
Abstract
A novel, simple and rapid spectrophotometric method for the determination of nitrophenol (NP) isomer mixtures based on the catalytic activity of gold nanoparticles is described. Gold nanoparticle (∼13 nm) solution was used to catalyze the reduction of NP isomers to aminophenols with an excess amount of NaBH4. The second-order data were obtained by spectrophotometrically monitoring the reduction process of NP isomers. So, multivariate curve resolution optimized by alternative least squares (MCR-ALS) was used to analyze such data. MCR-ALS, an appropriate second-order method, can exploit the so-called 'second order advantage' (the ability to determine in the presence of uncalibrated...
Useful multivariate kinetic analysis: Size determination based on cystein-induced aggregation of gold nanoparticles
, Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 115 , 2013 , Pages 588-594 ; 13861425 (ISSN) ; Nezhad, M. R. H ; Abdollahi, H ; Sharif University of Technology
2013
Abstract
This study describes spectrometric monitored kinetic processes to determine the size of citrate-capped Au nanoparticles (Au NPs) based on aggregation induced by L-cysteine (L-Cys) as a molecular linker. The Au NPs association process is thoroughly dependent on pH, concentration and size of nanoparticles. Size dependency of aggregation inspirits to determine the average diameters of Au NPs. For this aim the procedure is achieved in aqueous medium at pH 7 (phosphate buffer), and multivariate data including kinetic spectra of Au NPs are collected during aggregation process. Subsequently partial least squares (PLS) modeling is carried out analyzing the obtained data. The model is built on the...
Estimation of 3-D pore network coordination number of rocks from watershed segmentation of a single 2-D image
, Article Advances in Water Resources ; Volume 94 , 2016 , Pages 264-277 ; 03091708 (ISSN) ; Ayatollahi, S ; Kharrat, R ; Dashti, N ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
In this study, we have utilized 3-D micro-tomography images of real and synthetic rocks to introduce two mathematical correlations which estimate the distribution parameters of 3-D coordination number using a single 2-D cross-sectional image. By applying a watershed segmentation algorithm, it is found that the distribution of 3-D coordination number is acceptably predictable by statistical analysis of the network extracted from 2-D images. In this study, we have utilized 25 volumetric images of rocks in order to propose two mathematical formulas. These formulas aim to approximate the average and standard deviation of coordination number in 3-D pore networks. Then, the formulas are applied...
The effects of annular electromagnetic stirring parameters on microstructure evolution of rheocast AZ91 magnesium alloy
, Article Journal of Materials Research and Technology ; Volume 8, Issue 2 , 2019 , Pages 2300-2308 ; 22387854 (ISSN) ; Aashuri, H ; Sharif University of Technology
Elsevier Editora Ltda
2019
Abstract
In the present study, an annular electromagnetic stirrer was used to fabricate the semi-solid slurry of AZ91 magnesium alloy under various conditions of electromagnetic intensities and times. The fabricated semi-solid slurry was injected into a step-die cavity, using a hydraulic jack with ram speed of 1 m/s. The effects of electromagnetic intensity, stirring time and step thicknesses on the microstructure evolution, shape factor, globules equivalent diameter, solid fraction and microhardness of samples were investigated. The experimental results showed that obtained optimal parameters of electromagnetic stirring were 55 (A) stirring current and 30 (s) stirring time. In this conditions, the...