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,...

Aerodynamic Design of 100 kW Transonic Ducted Fan

, M.Sc. Thesis Sharif University of Technology Shayan Fakhr, Atefeh (Author) ; Ghorbanian, Kaveh (Supervisor)

Abstract

The purpose of this research is the aerodynamic design of a 100 kW transonic ducted fan. Today, the aviation industry is moving towards the design of electric driven aircraft propulsion. Transonic ducted fans are one of the viable options that have been used in medium and heavy aircrafts due to their high specific power. In this research, the meanline model has been used for the initial design. By applying the design constraints, design limitations, design and functional parameters, the initial design point is found and then a sensitivity analysis is performed with respect to the effective design parameters to obtain the optimal design point. For the initial design of the transonic ducted...

Techno-Economic Comparison of Different Gas Turbine Inlet Cooling Techniques

, M.Sc. Thesis Sharif University of Technology Shayan, Mahdi (Author) ; Hakkaki Fard, Ali (Supervisor)

Abstract

Inlet air cooling is a simple and economical method to increase the power output of gas turbines. High-pressure fogging systems and mechanical chillers are two common methods. High water consumption, damage to compressor blades by water droplets, and inefficiency in humid climates are disadvantages of high-pressure fogging systems. Mechanical chillers have high electricity consumption and initial costs. In this research, an earth-to-air heat exchanger (EAHE) is introduced as a new method for inlet air cooling of gas turbines and is technically and economically compared with the two common methods in the long term in the climate of Tehran city. Temperature distribution in the ground is...

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...

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...

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...

Design and Optimization of Carbon Capture System from Exhaust Gases in the Process Industries

, M.Sc. Thesis Sharif University of Technology Farshi Taghavi, Mahdis (Author) ; Rashtchian, Davood (Supervisor) ; Seif, Shayan (Co-Supervisor)

Abstract

Carbon dioxide is one of the main geenhouse gases emitted from factories as well as transportation vehicles that adversely affect the atmosphere and cause global warming. Among the proposed solutions to reduce carbon dioxide in the atmosphere, carbon dioxide separation would be the most viable medium-term approach. However, the high cost of carbon dioxide separation prevents the development of carbon dioxide absorption technologies. Therefore, it seems that integrating separation and production processes is the most efficient way to save energy and reduce carbon emissions. This method decrease a high proportion of the energy consumption in upstream operations (carbon dioxide removal,...