Loading...
Search for: afrasiabi--yaser
0.058 seconds

    Ro brine treatment and disposal methods

    , Article Desalination and Water Treatment ; Volume 35, Issue 1-3 , Aug , 2011 , Pages 39-53 ; 19443994 (ISSN) Afrasiabi, N ; Shahbazali, E ; Sharif University of Technology
    Taylor and Francis Inc  2011
    Abstract
    More than 50 percent of countries in the world will likely face water stress or water shortages by 2025, and by 2050, as much as 75 percent of the world's population could face water scarcity. Desalination technologies, particularly the reverse osmosis (RO) process, have increasingly been adopted to produce freshwater from alternative sources such as seawater and brackish water due to water scarcity. However, desalination applications have always been limited by the disposal costs of RO brine and the adverse impact of brine on the receiving environment. The scope of this paper is to identify technically and commercially RO brine disposal and treatment methods such as deep well injection,... 

    Development of Submicron/Nanostructured HSLA Steel Using Thermomechanical Treatment

    , M.Sc. Thesis Sharif University of Technology Afrasiabi, Yaser (Author) ; Karimi Tahri, Ali (Supervisor)
    Abstract
    Nanocrystalline steel was developed by severe cold-rolling and subsequent annealing of HSLA steel with an original microstructure of lath martensite. Specimens are austenitized at 1000 ºC for 30 min followed by quenching in brine. The quenched specimens are cold rolled with 80% to 90 % reduction and then annealed at temperatures from 400 to 700ºC for 10 to 120 min.The specimens annealed at temperature 500oC for 60 min showed the multiphased ultrafine structure composed of equiaxed ultrafine ferrite grains with the mean grain size of 180 nm, nano-carbides distributed uniformly and blocks of tempered martensite. The produced nanostructured steel exhibited a yield stress and UTS, of 1280 MPa... 

    Automatic Headline Generation for Persian News Texts

    , M.Sc. Thesis Sharif University of Technology Afrasiabi, Shayan (Author) ; Ghassem-Sani, Gholamreza (Supervisor)
    Abstract
    The news headlines should represent the main and the most important topics of their stories. The task of selecting an appropriate headline for news stories is mainly done by journalists. The goal of this project has been the design and implementation of a system to automate this task, that is generating headlines for news. This task has been done for Persian news stories. There are various methods for automatic headline generation in English and some other languages, but no work has been done for Persian, yet. Thus, we have adopted some of the ideas from those methods, and do the remaining by our initiation. Our proposed method consists of three main parts: keyword extraction, most important... 

    Optimum design of R.O. membrane by using simulation techniques

    , Article Desalination and Water Treatment ; Volume 9, Issue 1-3 , 2009 , Pages 189-194 ; 19443994 (ISSN) Afrasiabi, N ; Ehteshami, M ; Ardakanian, R ; Sharif University of Technology
    2009
    Abstract
    Increasing demand of fresh water, and limitation water resources, with respect to world economic growth brings up the importance of utilization of saline water. At the current research the sensitivity analysis of ROSA was conducted. For this analysis, a single stage reverse osmosis is designed for well water specifi cation in southern Tehran under following condition: Feed fl ow: 40 m3/h and membrane Element: BW30–400 FR. The sensitivity analyses for all chemical element of base water were performed. As a result of sensitivity analysis shortest sensitivity gap, belongs to boron, and longest sensitivity gap, belongs to calcium. Which refl ects, under the same conditions, the least element to... 

    Multi-Stream Multiphase Flow Plate Fin Heat Exchanger Design Optimization to Reduce Pressure Drop and Improve Efficiency

    , M.Sc. Thesis Sharif University of Technology Afrasiabi, Mohammad Hassan (Author) ; Afshin, Hossein (Supervisor)
    Abstract
    Optimization of Plate-Fin Heat Exchnagers, which have various applications in different cryogenic processes nowadays, can have a significant role in improving process efficiency as well as decreasing their capital and operationl costs. In this study, is introduced a procedure to optimize the performance of multi-stream multi-phase Plate-Fin Heat Exchangers, implementing Genetic Algorithm optimization method. In this study, the simulation of the multi-stream multi-phase Plate-Fin Heat Exchanger is carried out by Aspen EDR, a leading software in simulation and design of different types of heat exchangers. The software is then integrated to external software to automate the simulation... 

    Accumulative roll bonding and post-deformation annealing of Cu-Al-Mn shape memory alloy

    , Article Journal of Materials Engineering and Performance ; Vol. 23, issue. 12 , 2014 , pp. 4429-4435 ; ISSN: 1544-1024 Moghaddam, A. O ; Ketabchi, M ; Afrasiabi, Y ; Sharif University of Technology
    2014
    Abstract
    Accumulative roll bonding is a severe plastic deformation process used for Cu-Al-Mn shape memory alloy. The main purpose of this study is to investigate the possibility of grain refinement of Cu-9.5Al-8.2Mn (in wt.%) shape memory alloy using accumulative roll bonding and post-deformation annealing. The alloy was successfully subjected to 5 passes of accumulative roll bonding at 600 °C. The microstructure, properties as well as post-deformation annealing of this alloy were investigated by optical microscopy, scanning electron microscopy, x-ray diffraction, differential scanning calorimeter, and bend and tensile testing. The results showed that after 5 passes of ARB at 600 °C, specimens... 

    Iran’s oil development scenarios by 2025 [electronic resource]

    , Article Energy Policy ; Volume 56, May 2013, Pages 612-622 Abbaszadeh, Payam ; Sharif University of Technology

    Imaging Method To Detect Low Probability of Intercept Radars

    , Ph.D. Dissertation Sharif University of Technology Hejazi Kookamari, Farzam (Author) ; Nayebi, Mohammad Mahdi (Supervisor) ; Norouzi, Yaser (Co-Advisor)
    Abstract
    In this thesis, a new passive method suitable for Geolocating LPI radars is introduced. The method uses two Electronic Support (ES) receivers placed on a fast moving platform (e.g., an airplane or a satellite). The proposed method has a high processing gain, which makes it highly suitable for very weak LPI signals. The processing gain of the method was analytically derived and illustrated with simulation to determine if the proposed method can detect LPI radars in much lower SNRs compared to regular time-frequency LPI detection methods. Also, the resolution of the proposed method in both range and cross-range direction in radar location finding was analyzed. Furthurmore, the effect of the... 

    Modelling the Physics of Collective Decision Making and Commuication by Signal Exchange

    , Ph.D. Dissertation Sharif University of Technology Salahshour Mehmandoust Olia, Mohammad (Author) ; Rouhani, Shahin (Supervisor) ; Roudi, Yaser (Co-Supervisor)
    Abstract
    In many biological populations, information about environmental conditions is acquired collectively, through information sharing among individuals, by exchanging signals. In order to achieve a better understanding of such systems, using methods borrowed from statistical physics, we introduce two mathematical models. First, a collective decision making model, for a community of individuals residing on a communication network, who live in an uncertain environment, in which individuals try to collectively find the environmental state. In the second model, a collective movement model, we consider a population of collectively moving individuals, in which individuals try to collectively find and...