Search for: semnani--f
0.101 seconds

    Recovery of uranium from UCF liquid waste by anion exchange resin CG-400: Breakthrough curves, elution behavior and modeling studies

    , Article Annals of Nuclear Energy ; Volume 54 , April , 2013 , Pages 149-153 ; 03064549 (ISSN) Tavakoli, H ; Sepehrian, H ; Semnani, F ; Samadfam, M ; Sharif University of Technology
    Continuous fixed-bed column studies were carried out by using Amberlite CG-400 anion exchange resin for the recovery of uranium from aqueous solutions (synthetic solutions and uranium conversion facility (UCF) liquid waste). Effects of operating parameters such as flow rate and bed height were studied. The breakthrough capacity decreases with increasing flow rate, but this dependence was not significant with a long column. The maximum breakthrough capacity of uranium ions were achieved by CG-400 resin at a flow rate of 0.2 mL min-1 and bed height 9.1 cm (4 g resin). The elution behavior of uranium from CG-400 resin by various eluents have been investigated and the results show that 0.5 mol... 

    Uranium recovery from UCF liquid waste by nanoporous MCM-41: Breakthrough capacity and elution behavior studies

    , Article Research on Chemical Intermediates ; Volume 39, Issue 3 , 2013 , Pages 951-959 ; 09226168 (ISSN) Mousavi, S. M ; Tavakoli, H ; Samadfam, M ; Semnani, F ; Asadi, Z ; Sepehrian, H ; Sharif University of Technology
    Adsorption and recovery of uranium by nanoporous MCM-41 from aqueous solutions (synthetic solution and uranium conversion facility liquid waste) were investigated by use of a fixed-bed column (1.2 cm diameter and 3.0 cm height). Adsorption was carried out at flow rates 0.2 and 0.5 mL min-1, which correspond to retention times of 10 and 6 min. The maximum breakthrough capacity for uranium ions was achieved by use of nanoporous MCM-41 at the optimum pH of 3.6 and flow rate 0.2 mL min-1 (61.95 μg g-1). The Thomas and Yan models were applied to the experimental data, by use of linear regression, to determine the characteristics of the column for process design. The breakthrough curves calculated... 

    Essential Oil Composition of Chenopodium botrys L. from Iran

    , Article Journal of Essential Oil-Bearing Plants ; Volume 10, Issue 4 , 2007 , Pages 314-317 ; 0972060X (ISSN) Morteza Semnani, K ; Babanezhad, E ; Sharif University of Technology
    The composition of the essential oil obtained from the dried flowering aerial parts of Chenopodium botrys L. (Chenopodiaceae) was analyzed by GC and GC-MS. Forty-one components have been identified in the essential oil of C. botrys. The major components of the essential oil were γ-terpineol (52.8%), p-cymene (19.0%) and iso-ascaridole (7.0%). © 2007 Taylor & Francis Group, LLC  

    The essential oil composition of marrubium vulgare l. From Iran

    , Article Journal of Essential Oil Research ; Volume 20, Issue 6 , 2008 , Pages 488-490 ; 10412905 (ISSN) Morteza Semnani, K ; Saeedi, M ; Babanezhad, E ; Sharif University of Technology
    The composition of the essential oil obtained from the dried flowering aerial parts of Marrubium vulgare L. (Labiatae) was analyzed by GC and GC/MS. Twenty components have been identified in the essential oil of M. vulgare. The major constituents of the essential oil were β-bisabolene (20.4%), δ-cadinene (19.1%) and isocaryophyllene (14.1%). © 2008, Taylor & Francis Group, LLC. All rights reserved  

    Uranium(VI) sorption behavior onto amberlite CG-400 anion exchange resin: Effects of pH, contact time, temperature and presence of phosphate

    , Article Annals of Nuclear Energy ; Volume 48 , October , 2012 , Pages 21-24 ; 03064549 (ISSN) Semnani, F ; Asadi, Z ; Samadfam, M ; Sepehrian, H ; Sharif University of Technology
    Elsevier  2012
    In this paper, uranium sorption onto amberlite CG-400 anion exchange resin in the presence of phosphate anions was studied. The effect of contact time between the sorbent and aqueous solution, pH, initial concentration of uranium and temperature were also investigated. Kinetic studies show that uranium sorption onto amberlite CG-400 resin in the presence of phosphate is a fast process and follows pesudo-second-order kinetics. It was also found that the pH value and the presence of phosphate play very important roles in the uranium sorption onto CG-400 resin. Optimum pH for uranium sorption in the presence of phosphate anions was about 3.5. The experimental sorption isotherm is successfully... 

    Proposing a Method for Ranking Nodes in Complex Networks

    , M.Sc. Thesis Sharif University of Technology Esnaashari, Marzieh (Author) ; Mahlooji, Hashem (Supervisor) ; Safaei Semnani, Farshad (Co-Supervisor)
    A distinct viewpoint is adopted by each centrality to analyze a network and rank its nodes. This study aims to introduce a novel centrality that ranks the nodes of a network more effectively. In this respect, a function of five centralities, namely betweenness, closeness, agent vector, degree, and Katz, is introduced to maximize the connected components of the network after ranking its nodes and deleting the first twenty ones. The proposed centrality functions better than the other mentioned centralities. Among the networks simulated to evaluate the centrality, it functions better in Erdos-Renyi and small-world networks, both of whom being based on the Poisson degree distribution, and... 

    Uranium Recovery From Liquid Waste of UCF Plant With Ion Exchange Resin Method in Continuous Mode

    , M.Sc. Thesis Sharif University of Technology Semnani, Fatemeh (Author) ; Samadfam, Mohammad (Supervisor) ; Sepehrian, Hamid (Supervisor) ; Ghasemi, Mohammad Reza (Co-Advisor)
    During various stages of processing uranium in Uranium conversion facility (UCF) in Isfahan, significant amounts of liquid waste is produced which leads to evaporation ponds. Since the concentration of uranium in evaporation ponds is relatively high, it seems to addition to environmental issues with recycled uranium from existing pools is also economically. Various physical and chemical methods for removal of uranium waste is used such as solvent extraction, ion exchange, chemical precipitation, membrane processes, etc. Each method has advantages and disadvantages. The ion exchange method, The due to lower cost, less acid pollution with organic copmpounds, convenience and high selectivity... 

    Evaluation of the interfacial activity of imidazolium-based ionic liquids and their application in enhanced oil recovery process

    , Article Journal of Molecular Liquids ; Volume 362 , 2022 ; 01677322 (ISSN) Hosseinzadeh Semnani, R ; Salehi, M. B ; Mokhtarani, B ; Sharifi, A ; Mirzaei, M ; Taghikhani, V ; Sharif University of Technology
    Elsevier B.V  2022
    Ionic liquids (ILs) are a growing trend in Enhanced Oil Recovery (EOR) studies as alternatives to commercial surfactants due to their environmentally friendly nature, and their resistance in harsh temperatures and salinities. ILs are customizable and come in an immense variety, and therefore, it is vital that different combinations of cation/anion be investigated for use in the industry. In this work, experiments are designed and performed to evaluate novel ILs’ surface activity and performance in a lab-scale EOR set-up, compatible with Iranian oil reservoir conditions. Three imidazolium-based ionic liquids were used, namely, butyl-methylimidazolium nitrate, hexyl-methylimidazolium nitrate,... 

    Evaluation of the Surface Activity of Novel Ionic Liquids and Their Application in the Enhanced Oil Recovery Process

    , M.Sc. Thesis Sharif University of Technology Hosseinzadeh Semnani, Radman (Author) ; Taghikhani, Vahid (Supervisor) ; Mokhtarani, Babak (Supervisor) ; Baghban Salehi, Mahsa (Co-Supervisor)
    The following dissertation discusses Ionic Liquids (ILs) as an alternative to commercial surfactants for use in the Enhanced Oil Recovery process. Ionic Liquids came to researchers’ attention due to their environmental nature and their tolerance for high temperatures and salinity. In this work, firstly, an extensive literature review is carried out, and then, experiments are designed and performed to evaluate ILs’ surface activity and performance in a lab-scale EOR set-up. The Ionic Liquids used in this work consist of three types of methylimidazolium nitrate, [MIM]+[NO3]-, with three different alkyl chain lengths. This combination, and specifically the effect of nitrate anions on EOR and... 

    Effect of heating profile on desorption curve in temperature programmed desorption analysis: Case study of acid sites distribution of SAPO-34

    , Article Journal of Porous Materials ; Volume 16, Issue 5 , 2009 , Pages 599-603 ; 13802224 (ISSN) Izadbakhsh, A ; Farhadi, F ; Khorasheh, F ; Yan, Z. F ; Sharif University of Technology
    Comparison of the traditional linear heating method of TPD with an original stepwise heating scheme was reported for the first time. Stepwise heating TPD was carried out by keeping the temperature constant as soon as ammonia desorption signal rises until the signal returns to the baseline. More ammonia desorption peaks on a SAPO-34 catalyst were identified using TPD with stepwise heating. The effect of temperature ramp on desorption peak broadening in TPD curve was also addressed. The more distinct ammonia desorption peaks in stepwise TPD indicates that ammonia adsorbs in about five or six different ways on SAPO-34, and attribution of different adsorptions may be explained considering some... 

    Theoretical and experimental study of cascade solar stills

    , Article Solar Energy ; Volume 90 , April , 2013 , Pages 205-211 ; 0038092X (ISSN) Ziabari, F. B ; Sharak, A. Z ; Moghadam, H ; Tabrizi, F. F ; Sharif University of Technology
    Most part of Iran is dominated by arid and semi-arid areas due to low annual rainfall. The need for production of fresh water from brackish water is considerably high, especially in dry regions. In this study 1 month daily-based experimental data from a solar still site has been reported. The technical and operational problems of this site which finally contributed to the total cease of the site are described. Then a detailed analysis is investigated on progress of a prototype which constructed in order to solve the site's problems. The results of 1 month of experimental data of the final design showed that the last prototype could be used to solve the current problems of the site. The... 

    Application of a continuous kinetic model for the hydrocracking of vacuum gas oil

    , Article Petroleum Science and Technology ; Vol. 32, Issue. 18 , 2014 , Pages 2245-2252 ; ISSN: 10916466 Arefi, A ; Khorasheh, F ; Farhadi, F ; Sharif University of Technology
    Hydrocracking is one of the most versatile petroleum refining processes for production of valuable products including gasoline, gas oil, and jet fuel. In this paper, a five-parameter continuous lumping model was used for kinetic modeling of hydrocracking of vacuum gas oil (VGO). The model parameters were estimated from industrial data obtained from a fixed bed reactor operating at an average temperature of 400°C and residence time of 0.3 h. Product distributions were obtained in terms of the weight fraction of various boiling point cuts. The model parameters were estimated using the Nelder-Mead optimization procedure and were correlated with temperature. Comparison of experimental and... 

    An improved methodology for design of custom-made hip prostheses to be fabricated using additive manufacturing technologies

    , Article Rapid Prototyping Journal ; Volume 18, Issue 5 , 2012 , Pages 389-400 ; 13552546 (ISSN) Rahmati, S ; Abbaszadeh, F ; Farahmand, F ; Sharif University of Technology
    Emerald  2012
    Purpose - The purpose of this paper is to present an improved methodology for design of custom-made hip prostheses, through integration of advanced image processing, computer aided design (CAD) and additive manufacturing (AM) technologies. Design/methodology/approach - The proposed methodology for design of custom-made hip prostheses is based on an independent design criterion for each of the intra-medullary and extra-medullary portions of the prosthesis. The intra-medullar part of the prosthesis is designed using a more accurate and detailed description of the 3D geometry of the femoral intra-medullary cavity, including the septum calcar ridge, so that an improved fill and fit performance... 

    Evaluation and enhancing of operational performance and training objective in accordance with Line Operations Safety Audit (LOSA)

    , Article International Air Safety Seminar Proceedings, 1 November 2011 through 3 November 2011 ; November , 2011 , Pages 78-99 ; 02705176 (ISSN) ; 9781618393975 (ISBN) Khoshkhoo, R ; Goodarzi, F ; Sharafbafi, F ; Sharif University of Technology

    Real-time impulse noise suppression from images using an efficient weighted-average filtering

    , Article IEEE Signal Processing Letters ; Volume 22, Issue 8 , 2015 , Pages 1050-1054 ; 10709908 (ISSN) Hosseini, H ; Hessar, F ; Marvasti, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    In this letter, we propose a method for real-time high density impulse noise suppression from images. In our method, we first apply an impulse detector to identify the corrupted pixels and then employ an innovative weighted-average filter to restore them. The filter takes the nearest neighboring interpolated image as the initial image and computes the weights according to the relative positions of the corrupted and uncorrupted pixels. Experimental results show that the proposed method outperforms the best existing methods in both PSNR measure and visual quality and is quite suitable for real-time applications  

    Kinetic modeling of pyrolysis of scrap tires

    , Article Journal of Analytical and Applied Pyrolysis ; Volume 84, Issue 2 , 2009 , Pages 157-164 ; 01652370 (ISSN) Mazloom, G ; Farhadi, F ; Khorasheh, F ; Sharif University of Technology
    The disposal of used tires is a major environmental problem. With increasing interest on recovery of wastes, pyrolysis is considered as an alternative process for recovering some of the value in scrap tires. An accurate kinetic model is required to predict product yields during thermal or catalytic pyrolysis of scrap tires. Pyrolysis products contain a variety of hydrocarbons over a wide boiling range. A common approach for kinetic modeling of such complex systems is lumping where each lump is defined by a boiling point range. Available experimental data for thermal and catalytic pyrolysis of scrap tires from the literature were used to evaluate two types of lumping models; discrete and... 

    Determine oil content in petroleum waxes

    , Article Hydrocarbon Processing ; Volume 85, Issue 6 , 2006 , Pages 95-97 ; 00188190 (ISSN) Mafi, M ; Yazdani, F ; Farhadi, F ; Sharif University of Technology

    Analytical modeling of variable-reluctance tubular resolver based on magnetic equivalent circuit and conformal mapping

    , Article IEEE Transactions on Instrumentation and Measurement ; Volume 70 , 2021 ; 00189456 (ISSN) Keyvannia, A ; Zare, F ; Tootoonchian, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Compared with flat linear structures, tubular linear machines do not face edge effects, making their performance better than their flat counterparts. In this article, a novel linear variable-reluctance resolver with tubular configuration is proposed. To optimize the design of an electromagnetic structure, modeling methods are used. Thus, in this article, an analytical model for the proposed resolver is presented. This model is based on the magnetic equivalent circuit (MEC) method and is considerably less time-consuming than finite element analysis (FEA), yet provides accurate results. A conformal mapping is employed to compute the permeance of the air-gap. The proposed model is then utilized... 

    Information and the Brukner-Zeilinger interpretation of quantum mechanics: A critical investigation

    , Article Foundations of Physics Letters ; Volume 19, Issue 1 , 2006 , Pages 1-20 ; 08949875 (ISSN) Shafiee, A ; Safinejad, F ; Naqsh, F ; Sharif University of Technology
    In Brukner and Zeilinger's interpretation of quantum mechanics, information is introduced as the most fundamental notion and the finiteness of information is considered as an essential feature of quantum systems. They also define a new measure of information which is inherently different from the Shannon information and try to show that the latter is not useful in defining the information content in a quantum object. Here, we show that there are serious problems in their approach which make their efforts unsatisfactory. The finiteness of information does not explain how objective results appear in experiments and what an instantaneous change in the so-called information vector (or catalog of... 

    Key parameters in hydrothermal synthesis and characterization of low silicon content SAPO-34 molecular sieve

    , Article Microporous and Mesoporous Materials ; Volume 126, Issue 1-2 , 2009 , Pages 1-7 ; 13871811 (ISSN) Izadbakhsh, A ; Farhadi, F ; Khorasheh, F ; Sahebdelfar, S ; Asadi, M ; Yan, Z. F ; Sharif University of Technology
    Low silicon content SAPO-34 was successfully synthesized using the conventional hydrothermal crystallization in the static condition. Effects of different synthesis conditions including crystallization temperature and the silicon source were investigated through X-ray diffraction patterns. It was concluded that the silicon source had a significant effect on silicon incorporation into the alumino-phosphate building blocks in the course of crystallization. Using precipitated silica instead of silica sol resulted in the formation of impurities of alumino-phosphates phases whose crystalline structures collapse at the high temperature of calcination. For the low silicon SAPO-34 synthesis, the...