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Total 89 records

    Newton's Method for Vector Optimization

    , M.Sc. Thesis Sharif University of Technology Jalalian, Saeideh (Author) ; Razvan, Mohammad Reza (Supervisor) ; Khorram, Esmaeil (Supervisor)

    Optimization of Encapsulation of Probiotic Living Cells

    , M.Sc. Thesis Sharif University of Technology Sajjadi Dehkordi, Sahar (Author) ; Alemzadeh, Iran (Supervisor)
    Abstract
    In the recent year, there has been a rising interest in producing functional foods containing encapsulated probiotic bacteria according to their perceived health benefits. Probiotics are feed and food supplements that beneficially affect the host’s health. The term “probiotic” includes a large range of microorganisms, mainly lactic acid bacteria. Because they can stay alive until the intestine and provide health beneficial effects like lowering cholesterol, improving lactose tolerance and preventing some cancers like colon cancer on the host health. It has been recommended that the viability of probiotics should be at least 107 CFU/ml of product at time of consumptions to provide selective... 

    Tunable photon statistics in a non-Hermitian system

    , Article Journal of the Optical Society of America B: Optical Physics ; Volume 34, Issue 3 , 2017 , Pages 566-573 ; 07403224 (ISSN) Shakeri, S ; Zandi, M. H ; Bahrampour, A ; Sharif University of Technology
    OSA - The Optical Society  2017
    Abstract
    In the present study, the antibunching effect is considered in a parity time (PT)-symmetric system, using the recently proposed non-Hermitian model for resonant cavities. The model consists of a cavity coupled to an optomechanical system by a chiral mirror, with both cavities being driven coherently. The nonreciprocal coupling strength between the two cavities leads to the generation of the non-Hermitian but PT-symmetric model. The optimal conditions of strong antibunching are calculated in this system, and then the antibunching effect is considered using the two-photon correlation function and the Wigner function. The results showed that this model presented the best control over the strong... 

    Application of Ultrasonic Technique to Improve Food Processing and Yield Enhancement in Food Industry

    , M.Sc. Thesis Sharif University of Technology Halalipour, Ali (Author) ; Roosta Azad, Reza (Supervisor) ; Aalemzadeh, Iran (Supervisor) ; Ghotbi, Siroos (Supervisor)
    Abstract
    In this project we focused on Ultrasonic waves as novel, effective and well-controllable means for cell wall disruption and disintegration to provide faster and more complete penetration of solvent into cellular materials and improve sugar mass transfer and extraction from sugarcane and sugar beet. Impact of frequency, temperature, power density and reactor shape on Ultrasonic wave efficiency in extraction process has been investigated and the result was utilized to design a semi-pilot reactor. In the optimum situation, sucrose extraction from sugarcane improved to 4.51 gr/100 ml H2O that had a significant increasing from 2.1 gr/100 ml H2O extraction in thermal only process at 70 °C. Optimum... 

    Investigation and Optimization of Structural Parameters of an Elastic Flapping Wing

    , M.Sc. Thesis Sharif University of Technology Badri Kouhi, Ehsan (Author) ; Dehghani Firouzabadi, Roohollah (Supervisor)
    Abstract
    In this thesis, effects of bending and torsional elasticity of a flapping wing on its average lift and input power are studied, using a semi-analytic method. Bending stiffness and torsional rigidity of wing spar, wing mass ratio and chordwise and spanwise center of gravity, also spar location are considered as variables for controlling elastic behavior of the wing.Governing integral equation is derived using Hamilton principle via modified quasi aerodynamic and linear Green-Lagrange strain tensor. Also an idealized flapping pattern is used to maximize average acceleration during each cycle. Next, integral equation is converted to a set of ordinary differential equations by means of Galerkin... 

    Note on Local Quadratic Growth Estimates in Bang-Bang Optimal Control Problems

    , M.Sc. Thesis Sharif University of Technology Daviran, Morteza (Author) ; Hesaaraki, Mahmoud (Supervisor)
    Abstract
    In optimal control,local quadratic growth estimation in case of continuous control functions, and for bang–bang optimal controls when the state system is linear, has been obtained. The paper provides a generalization of the latter result to bang–bang optimal control problems for systems which are affine-linear w.r.t. the control but depend nonlinearly on the state.Local quadratic growth in terms of L1 norms of the control variation are obtained under appropriate structural and second-order sufficient optimality conditions  

    A horizontally oriented setup for liquid-liquid-liquid microextraction of estrogens

    , Article Analytical Methods ; Volume 5, Issue 22 , 2013 , Pages 6517-6522 ; 17599660 (ISSN) Bagheri, H ; Maleki, H ; Es'Haghi, A ; Sharif University of Technology
    2013
    Abstract
    A horizontally oriented liquid-liquid-liquid microextraction (HOLLLME) setup was developed and applied for the isolation of two major estrogens from aquatic media. In contrast to the conventional procedure, in this setup the extracting microdrop was suspended from a horizontally positioned needle in order to provide much higher stability to the extracting phase. The developed HOLLLME approach was applied to isolate two major selected estrogens from aquatic media followed by high performance liquid chromatography-ultraviolet (HPLC-UV) determination. Estrogens were, initially, extracted from water samples into hexane and subsequently, the back extraction stage was performed with 6 μL of sodium... 

    A conically fixed position single drop microextraction method for isolation of aryloxyphenoxypropionate herbicides from aquatic media

    , Article Analytical Methods ; Volume 5, Issue 18 , Jul , 2013 , Pages 4846-4851 ; 17599660 (ISSN) Bagheri, H ; Dehghan, M ; Es'Haghi, A ; Naderi, M ; Sharif University of Technology
    2013
    Abstract
    A new and convenient format of single drop microextraction (SDME) was developed and applied for isolation of some selected aryloxyphenoxypropionate herbicides from aquatic media. In contrast to the conventional SDME procedure, in this set-up the extraction microdrop was positioned at the bottom of a conical vial in order to provide much higher stability for the organic extraction phase while a magnetic bar was used for stirring the aqueous solution. A simple magnet was used for positioning the bar on the top of the microdrop prior to stirring. The whole set-up led to the use of any volume of extraction solvent with unlimited stirring rates. Some important extraction parameters such as the... 

    Enhancement of L-asparaginase production by candida utilis in a 13L fermenter and its purification

    , Article International Journal of Engineering, Transactions B: Applications ; Volume 28, Issue 8 , 2015 , Pages 1133-1141 ; 1728-144X (ISSN) Momeni, V ; Alemzadeh, I ; Vosoughi, M ; Sharif University of Technology
    Materials and Energy Research Center  2015
    Abstract
    L- asparaginase enzyme is a renown enzyme because of its chemotherapeutic properties. This enzyme may also be employed in food processing technology. The present study aimed, optimizing the agitation and aeration rate in L-asparaginase production, using C. utilis, ATCC 9950 in batch fermentation system. Beet molasses used as the carbohydrate source for enzyme production. A maximum asparaginase activity of 245.6 U/ml obtained after 20h of fermentation under optimal condition of 1.25 vvm aeration rate and 300 rpm agitation speed. Purification of the enzyme was also done by Acetone Precipitation and column chromatograph. Purified L-asparaginase revealed molecular weight 75 kDa and 82.7 % yield... 

    Copper recovery from reverberatory furnace flue dust

    , Article International Journal of Mineral Processing ; Volume 157 , 2016 , Pages 205-209 ; 03017516 (ISSN) Mohagheghi, M ; Askari, M ; Sharif University of Technology
    Elsevier, B. V  2016
    Abstract
    In this study, leaching of reverberatory furnace dust at Sarcheshmeh was investigated in H2SO4-O3 medium. Response surface methodology based on central composite face-centered design (RSM-CCF) was applied to optimize the operating parameters. The optimal conditions to achieve the principle objectives of maximizing copper dissolution and minimizing iron dissolution from dust were identified to be a temperature of 30 °C, a leaching time of 3 h, an initial pH of 0.5, a pulp density of 20%, and an ozone flow rate of 1 g/h. Under the optimum conditions, the copper and iron concentrations in the leaching solution were found to be 27.11 and 0.90 g/L, respectively. The results showed that selective... 

    Polarity adjustment of a nanosilica-functionalized polyamine modified by ionic liquid for removal of Cu2+ from aqueous solutions

    , Article RSC Advances ; Volume 6, Issue 17 , 2016 , Pages 14128-14133 ; 20462069 (ISSN) Vafaeezadeh, M ; Mahmoodi Hashemi, M ; Ghavidel, N ; Sharif University of Technology
    Royal Society of Chemistry  2016
    Abstract
    The current work deals with modification of the surface of a silica-polyamine with amine-based ionic liquid (IL) and its application for removal of Cu2+ from an aqueous media. The absorbent is simply prepared from commercially available reagents. The material is characterized by FT-IR spectroscopy, thermogravimetric analysis (TGA), N2 adsorption-desorption, and transmission electronic microscopy (TEM). Effects of several parameters on absorption efficiency, as well as activity of the absorbent to other metals, are also investigated. Moreover, the reusability of the absorbent is studied at the optimized condition. © The Royal Society of Chemistry 2016  

    Scheduling for data centers with multi-level data locality

    , Article 2017 25th Iranian Conference on Electrical Engineering, ICEE 2017, 2 May 2017 through 4 May 2017 ; 2017 , Pages 927-936 ; 9781509059638 (ISBN) Daghighi, A ; Kavousi, M ; Sharif University of Technology
    Abstract
    One of the challenging problems in real-time data-parallel processing applications is to schedule tasks to different servers aiming to increase data locality for higher efficiency or lower delay, and at the same time, doing load balancing to stabilize the system of server-queues. We target this problem, and discuss efficient real-time task scheduling algorithms aimed not only to stabilize the system when the arrival rate is in the capacity region (i.e. throughput optimality condition), but also to minimize the mean delay of all tasks in heavy traffic regime when the arrival rate approaches the capacity boundary (i.e. heavy-traffic optimality condition). In this paper, we point out the data... 

    Conjugated linoleic acid production and optimization via catalytic reaction method using safflower oil

    , Article International Journal of Engineering, Transactions B: Applications ; Volume 31, Issue 8 , 2018 , Pages 1166-1171 ; 1728144X (ISSN) Afarin, M ; Alemzadeh, I ; Kouchak Yazdi, Z ; Sharif University of Technology
    Materials and Energy Research Center  2018
    Abstract
    Conjugated linoleic acid (CLA) is one of the most physiological active fatty acids due to its positive effect on prevention of diseases such as obesity, hyperlipidemia, atherosclerosis and cancer. The aim of this study was to optimize the production of conjugated linoleic acid (CLA)% in alkali isomerization of safflower oil including 71% linoleic acid (LA) using response surface methodology (RSM). The effect of three reaction variables such as temperature, reaction time and amount of KOH on CLA production was investigated using design-expert software. The optimal condition determined at this point, 72% total CLA with the yield of 84% temperature reaction time and the amount of KOH were 187.6... 

    Optimal condition for optical trapping of large particles: Tuning the laser power and numerical aperture of the objective

    , Article Journal of the Optical Society of America B: Optical Physics ; Volume 36, Issue 11 , 2019 , Pages 3053-3059 ; 07403224 (ISSN) Alinezhad, H. G ; Nader, S ; Reihani, S ; Sharif University of Technology
    OSA - The Optical Society  2019
    Abstract
    A Gaussian laser beam tightly focused through a high-numerical-aperture objective lens, so-called optical tweezers, is widely used for piconewton-range force spectroscopy. Utilizing a proper value for parameters such as bead size, numerical aperture of the objective, and power of the laser is always a challenge. Here, we show which set of values for the parameters can maximize lateral trapping efficiency. Our results show that for a high-numerical-aperture force spectroscopy, a bead with a diameter of 4–5 µm is suitable, and that for manipulation using large beads, utilizing a proper value for laser power and numerical aperture of the objective is crucial. We present a practical method for... 

    Optimal condition for optical trapping of large particles: Tuning the laser power and numerical aperture of the objective

    , Article Journal of the Optical Society of America B: Optical Physics ; Volume 36, Issue 11 , 2019 , Pages 3053-3059 ; 07403224 (ISSN) Gorjizadeh Alinezhad, H ; Nader, S ; Reihani, S ; Sharif University of Technology
    OSA - The Optical Society  2019
    Abstract
    A Gaussian laser beam tightly focused through a high-numerical-aperture objective lens, so-called optical tweezers, is widely used for piconewton-range force spectroscopy. Utilizing a proper value for parameters such as bead size, numerical aperture of the objective, and power of the laser is always a challenge. Here, we show which set of values for the parameters can maximize lateral trapping efficiency. Our results show that for a high-numerical-aperture force spectroscopy, a bead with a diameter of 4–5 µm is suitable, and that for manipulation using large beads, utilizing a proper value for laser power and numerical aperture of the objective is crucial. We present a practical method for... 

    Using genetic algorithm and artificial neural network analyses to design an Al-Si casting alloy of minimum porosity

    , Article Materials and Design ; Volume 27, Issue 7 , 2006 , Pages 605-609 ; 02641275 (ISSN) Mousavi Anijdan, S. H ; Bahrami, A ; Madaah Hosseini, H. R ; Shafyei, A ; Sharif University of Technology
    2006
    Abstract
    In this investigation a theoretical model based on artificial neural network (ANN) and genetic algorithm (GA) has been developed to optimize effective parameters on porosity formation in Al-Si casting alloys. The ANN theory was used to correlate the chemical composition and cooling rate to the amount of porosity. The GA and ANN were incorporated to find the optimal conditions for achieving the minimum porosity percent. By comparing the predicted values with the experimental data - earlier deduced by Dash et al. - it is demonstrated that the combined GA-ANN model is a useful and efficient method to find the optimal conditions for casting of Al-Si alloys associated with the minimum porosity... 

    Voltage security constrained multi-period optimal reactive power flow using benders and optimality condition decompositions

    , Article IEEE Transactions on Power Systems ; Volume 28, Issue 2 , 2013 , Pages 696-708 ; 08858950 (ISSN) Rabiee, A ; Parniani, M ; Sharif University of Technology
    2013
    Abstract
    This paper proposes a new coordinated voltage control scheme to ensure voltage security of power systems. The scheme schedules reactive power injection from VAR sources, including synchronous generators and condensers, capacitor banks, switchable reactors and FACTS devices, to ensure desired loading margin of power systems for a given horizon of time. The problem is treated as voltage security constrained multi-period optimal reactive power flow (VSC-MPORPF). To incorporate scheduling of both continuous and discrete VAR sources, the VSC-MPORPF is formulated as a mixed-integer nonlinear programming problem, and is solved using generalized Benders decomposition (GBD). Multi-period formulation... 

    Coordinated Voltage Control of Power Systems in Normal and Emergency Operation States

    , Ph.D. Dissertation Sharif University of Technology Rabiee, Abbas (Author) ; Parniani, Mostafa (Supervisor)
    Abstract
    One of the main objectives in operating a power system is to maintain the system voltage properly to avoid equipment damage and transfer power efficiently. Automatic control of transmission network voltage provides significant improvements in security, quality and efficiency of power system operation. This thesis investigates coordinated voltage control of power systems in normal, alert and emergency states. The aim is to propose a comprehensive framework for real-time operation of practical power systems, ensuring secure operation of the system in the normal state and after occurrence of sever contingencies.
    At the first, a new coordinated voltage control scheme is proposed to ensure... 

    , M.Sc. Thesis Sharif University of Technology (Author) ; Farhadi, Fathollah (Supervisor)
    Abstract
    The aim of this project is Industrial Solvents (White Spirit) producing in Tehran Refinery. For this manner “Wild Naphtha” from Gasoil Hydrotreater and Kerosene Hydrotreater Units was chosen as feed stock for solvents preparation. In addition, Pentane Recovery Column is selected for Simulation and Optimization based on Wild Naphtha. As a Result, Abadan White Spirit 402 and 410 has been produced and a side stream which is full of Aromatic is obtained. Simultaneously, Tray Hydraulics and Solvents production in different cases (Various Pressure and different Split Ratio of Feed Stock) are evaluated, so optimum Tower process conditions such as pressure, Temperature and Split Ratio of Feed Stock... 

    Optimal Control Problem for an Ecosystem With Two Competing Preys and One Predator

    , M.Sc. Thesis Sharif University of Technology Izadjoo, Majid (Author) ; Hesaraki, Mahmoud (Supervisor)
    Abstract
    this work devoted to the optimal control problem for an ecosystem composed of one predator and two competing preys, and our goal is to maximize the total density of the three populations. we first investigate the existence and uniqueness of the positive strong solution for the controlled system, and find an optimal solution under given initial conditions. then we establish the first order necessary optimality condition, and point out that the optimal control has a bang-bang form. moreover, the second order necessary and sufficient optimality conditions are established