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azizpour--rashid
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Transmission of High Quality Video over Mobile Ad hoc Networks
, M.Sc. Thesis Sharif University of Technology ; Ghanbari, Mohammad (Supervisor)
Abstract
Video communications over mobile ad hoc networks is increasingly deployable as these networks become deployed in various applications such as disaster recovery. Error-prone nature of the mobile ad hoc networks and the vulnerability of compressed video to packet losses have brought many challenges to realize video transmission over MANETs. In this thesis, it is tried to achieve a good quality of service by resilient video coding and multipath transmission over mobile ad hoc networks. To generate error resilient video, a hybrid method is used by combining scalable video coding and multiple description video coding techniques. First, the video sequence is coded to two layers and then each layer...
Design and Analysis of A Business Model Canvas Considering Entrepreneurship and New Product Development in a Fmcg Ecosystem
, M.Sc. Thesis Sharif University of Technology ; Fatahi Valilai, Omid (Supervisor)
Abstract
The business model is very important, as many researchers in this field believe that the success or failure of a business is highly dependent on right design and application of this model. In most recent innovation studies, application of innovation in business models or developing an innovative business model itself is one of the main factors to enable an organization to have stable status in the competitive market. This is unlike the traditional believes, which technology and process were the main motivators behind organization to stand out in competitive market. Designing a proper business model requires a system thinking approach, which considers both internal interactions factors, and...
Theoretical and industrial aspects of amine reclaiming unit to separate heat stable salts
, Article Separation and Purification Technology ; Volume 237 , 2020 ; Moradi, M ; Rostami, A ; Azizpour, H ; Sharif University of Technology
Elsevier B.V
2020
Abstract
In this study, a thermal vacuum distillation amine reclaimer unit was industrially and theoretically investigated to remove HSS from a salty amine stream. The presence of ions in the salty amine solution limits application of computer simulation tools to study the process. A thermodynamic equivalent scheme was used for thermal vacuum distillation amine reclaimer, for first time and the simulation results were totally conformed to experimental and industrial data. The effect of critical parameters namely reclaimer vacuum pressure, re-circulation flow rate and HSS amount on performance of thermal amine reclaiming was investigated based on increasing amine solution quality, amine recovery,...
Molecular Simulation of Adsorption of Surface-Modified Silica Nanoparticles at Liquid-Liquid Interfaces
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar (Supervisor)
Abstract
With rising oil prices and predictions about the future of hydrocarbon reserves, issues of enhanced oil recovery and optimal production of existing reservoirs are of particular importance. In this study, molecular dynamics simulation was used to study the absorption of silica nanoparticles with surface groups at the interface of water and decane. The effect of surface chemistry of silica nanoparticles on the interface properties of water-decane with changing the surface groups was simulated. The initial surface factor of nanoparticle is hydroxyl (OH), which is called a hydrophilic surface agent. Nanoparticles were modified by methyl and ethyl surface agents to increase the hydrophobicity and...
Prediction of CO2-Brine interfacial tension using a rigorous approach
, Article Journal of Natural Gas Science and Engineering ; Volume 45 , 2017 , Pages 108-117 ; 18755100 (ISSN) ; Harimi, B ; Hamidpour, E ; Sharif University of Technology
Elsevier B.V
2017
Abstract
Geologic sequestration of CO2 in deep saline aquifers is becoming increasingly important as a method with the greatest potential to economically sequester large volumes of anthropogenic CO2. The interfacial tension (IFT) between the formation brine in the aquifer and the injected CO2 phase has a significant influence on the displacement, and its precise determination is essential for accurate modeling and evaluation of such a process. This paper presents two new mathematical models to calculate the brine/CO2 IFT. The two models differ in input parameters; pressure, temperature, and salinity for the first model, and pressure, temperature, and brine composition for the second one. The proposed...
Analysis of Autonomous Takeoff and Landing of a Tailsitter on Moving Platform
, M.Sc. Thesis Sharif University of Technology ; Banazadeh, Afshin (Supervisor)
Abstract
The purpose of this research is to add automatic landing and takeoff capability to the target drone. To design the automatic landing and takeoff algorithm and analyze and check its performance quality, the target drone must be modeled first. Since this drone has a relatively large blade, the dynamic effects of this large blade are included in the modeling. After modeling the drone, the controller has been designed for three phases of horizontal flight, vertical flight and the transition between these two flight phases. With the preparation of the controllers of different phases of flight, the automatic landing and takeoff algorithm of the flying drone is designed, implemented and its results...
An intelligent modeling approach for prediction of thermal conductivity of CO2
, Article Journal of Natural Gas Science and Engineering ; Volume 27 , November , 2015 , Pages 138-150 ; 18755100 (ISSN) ; Esmaili, S ; Rashid, S ; Suleymani, M ; Sharif University of Technology
Elsevier
2015
Abstract
In the design of a carbon dioxide capture and storage (CCS) process, the thermal conductivity of carbon dioxide is of special concern. Hence, it is quite important to search for a quick and accurate determination of thermal conductivity of CO2 for precise modeling and evaluation of such a process. To achieve this aim, a robust computing methodology, entitled least square support vector machine (LSSVM) modeling, which is coupled with an optimization approach, was used to model this transport property. The model was constructed and evaluated employing a comprehensive data bank (more than 550 data series) covering wide ranges of pressures and temperatures. Before constructing the model, outlier...
Microstructural and mechanical properties (hardness) investigations of Al-alloyed ductile cast iron
, Article Journal of Alloys and Compounds ; Volume 500, Issue 1 , June , 2010 , Pages 129-133 ; 09258388 (ISSN) ; Naser Zoshki, H ; Kiani Rashid, A.R ; Sharif University of Technology
2010
Abstract
Microstructures and hardness of aluminum alloy ductile iron were investigated by SEM, XRD, EPMA and hardness measurement techniques. The results show, increasing the Al-alloying element leads to decrease of free ferrite and carbide, as well as increase in the pearlite volume fraction. It is also has been found that in the higher values of Al, about 85% of the matrix would be pearlite. It is indicated that an increase in the aluminum content also leads to a decrease in the spacing between pearlite layers. XRD results show, in the presence of Al, intermetallic compounds such as Al6Fe, AlFe3C0.5, Fe3Al and FeAl were produced. Furthermore the hardness measurements illustrate that by increasing...
The effect of varient heat treatment cycles on controlled surface graphitization in CK45 steel
, Article TMS Annual Meeting, 14 February 2010 through 18 February 2010 ; 2010 , Pages 59-70 ; 9781617822933 (ISBN) ; Hamedi, Y ; Shishegar, H. R ; Sharif University of Technology
2010
Abstract
Controlled graphitization has become known as a practical method for improvement of wear resistance and machining properties in steels. In this paper, the effect of heat treatment on microstructure of CK45 steel has been investigated. Austenitising was carried out at 920°C for 5 hours. Besides, isothermal transformation was conducted at 750°C in the time range of 1-20 hours. The microstructure of the steel considerably changes by this heat treatment process which exhibits the effects of temperature, appropriate austenitising duration and isothermal transformation. Conducted experiments show a suitable distribution of semi-spherical graphite particles especially on the surface of the steel....
Waveform design in MIMO radar using radial point interpolation method
, Article IEEE Communications Letters ; Volume 22, Issue 10 , 2018 , Pages 2076-2079 ; 10897798 (ISSN) ; Bolhasani, M ; Ghorashi, S. A ; Rashid, M ; Sharif University of Technology
2018
Abstract
In this letter, we consider the problem of waveform design in colocated multiple-input multiple-output radars in order to obtain a desired beampattern. In this problem, practical constraints, such as constant envelope (CE) and low peak-to-average power ratio, are very important. Therefore, we propose a simple method to generate some practical waveforms, such as different versions of phase-shift keying and pulse-amplitude modulation. We map a non-CE to the desired finite alphabet by a mapping function (MP). In the proposed method, first, the values of cross-correlation relationship between the input and the output of MP are calculated in a few points, and then, using radial point...
Behavior-based safety program for process industries
, Article International Journal of Occupational Safety and Ergonomics ; Volume 29, Issue 4 , 2023 , Pages 1440-1450 ; 10803548 (ISSN) ; Athar, M ; Noor, F ; Hussain, A ; Sharif University of Technology
Taylor and Francis Ltd
2023
Abstract
Objectives. This article describes the reduction of unsafe behaviors observed at a fertilizer complex by implementation of a behavior-based safety (BBS) program via a behavior observation form developed by a multidisciplinary team. Methods. Six observation categories, i.e., position of people, reaction of people, personal protective equipment (PPE), tools used, operating procedures and housekeeping, are used to monitor safe and unsafe behaviors for a period of 18 months. Results. Safe behaviors increased from 57 to 70% and unsafe behaviors reduced from 40 to 26%. Behaviors of employees working in various sections of fertilizer complex such as ammonia, urea, utility, bagging/shipping and...
An Artificial Neural Networks Model for Predicting Permeability Properties of Nano Silica-Rice Husk Ash Ternary Blended Concrete
, Article International Journal of Concrete Structures and Materials ; Volume 7, Issue 3 , September , 2013 , Pages 225-238 ; 22341315 (ISSN) ; Khaloo, A ; Iraji zad, A ; Abdul Rashid, S ; Sharif University of Technology
Korea Concrete Institute
2013
Abstract
In this study, a two-layer feed-forward neural network was constructed and applied to determine a mapping associating mix design and testing factors of cement-nano silica (NS)-rice husk ash ternary blended concrete samples with their performance in conductance to the water absorption properties. To generate data for the neural network model (NNM), a total of 174 field cores from 58 different mixes at three ages were tested in the laboratory for each of percentage, velocity and coefficient of water absorption and mix volumetric properties. The significant factors (six items) that affect the permeability properties of ternary blended concrete were identified by experimental studies which were:...
Investigating the effects of using different types of SiO2 nanoparticles on the mechanical properties of binary blended concrete
, Article Composites Part B: Engineering ; Volume 54, Issue 1 , 2013 , Pages 52-58 ; 13598368 (ISSN) ; Khaloo, A ; Iraji Zad, A ; Abdul Rashid, S ; Sharif University of Technology
2013
Abstract
The aim of this study was to assess the effects of two different types of SiO2 nanoparticles (N and M series) with different ratios on the workability and compressive strength of developed binary blended concretes cured in water and lime solution as two different curing media. N and M series SiO2 nanoparticles with an average size of 15 nm were used as obtained from the suppliers. Fresh and hardened concretes incorporating 0.5%, 1.0%, 1.5% and 2.0% of N and 2% of M series nanoparticles with constant water to binder ratio and aggregate content were made and tested. Fresh mixtures were tested for workability and hardened concretes were tested for compressive strength at 7, 28 and 90 days of...
Investigation on the effects of hot forging parameters on the austenite grain size of vanadium microalloyed forging steel (30MSV6)
, Article Journal of Alloys and Compounds ; Volume 490, Issue 1-2 , February , 2010 , Pages 572-575 ; 09258388 (ISSN) ; Ziaei, S. M. R ; Kiani Rashid, A. R ; Sharif University of Technology
2010
Abstract
It is known that the thermomechanical processing is one of the most important techniques for improving quality and mechanical properties of microalloyed steels. In this paper, the main parameters of hot forging (preheat temperature, strain and post-forging cooling rate) on the primary austenite grain size of vanadium microalloyed steel (30MSV6) were studied. From this investigation, it was found that increasing preheat temperature from 1150 °C to 1300 °C will result in a decrease in grain size number. Furthermore, it has shown that as the strain increases, the austenite grain size number increases, as is evident for the two cooling rates of 2.5 °C/s and 1.5 °C/s for primary austenite....
Effective surface modification of MnFe2O4@SiO2@PMIDA magnetic nanoparticles for rapid and high-density antibody immobilization
, Article Applied Surface Science ; Volume 426 , 2017 , Pages 1023-1029 ; 01694332 (ISSN) ; Soleimani, M ; Ghahremanzadeh, R ; Vossoughi, M ; Esmaeili, E ; Sharif University of Technology
2017
Abstract
The present study is aimed at the synthesis of MnFe2O4@SiO2@PMIDA in terms of highly efficient sensing platform for anti-prostate specific membrane antigen (PSMA) immobilization. Superparamagnetic manganese ferrite nanoparticles were synthesized following co-precipitation method and then SiO2 shell was coated on the magnetic core with tetraethyl orthosilicate (TEOS) through a silanization reaction to prevent oxidation, agglomeration and, increase the density of OH groups on the surface of MnFe2O4. Subsequently, MnFe2O4@SiO2@PMIDA obtained as a result of the reaction between N-(phosphonomethyl)iminodiacetic acid (PMIDA) and MnFe2O4@SiO2. The reactive carboxyl groups on the surface of magnetic...
Energy and chemicals production from coal-based technologies: a review
, Article ChemBioEng Reviews ; Volume 10, Issue 5 , 2023 , Pages 841-851 ; 21969744 (ISSN) ; Abdullahi Isah, U ; Athar, M ; Benhelal, E ; Sharif University of Technology
John Wiley and Sons Inc
2023
Abstract
Coal, a solid fossil fuel, consists of organic and inorganic matter. Its complex structure contains fused aromatic moieties, constituting a three-dimensional macromolecular coal structure network. More efficient utilisation technologies are required to ensure coal becomes a considerably cleaner source of energy in the future. Due to the increase in energy, liquid fuels, and combustible gas demands, coal utilisation is necessary for some developing countries such as Pakistan, Turkey, and India. Furthermore, coal is globally being used to produce liquid fuels and combustible gases. The benefits and drawbacks of various Fischer-Tropsch synthesis catalysts are discussed. For clean coal...
Experimental Study of Improved Oil Recovery by Low-Salinity Waterflooding in Asphaltenic Reservoirs
, M.Sc. Thesis Sharif University of Technology ; Ayatollahi, Shahaboddin (Supervisor) ; Vosoughi, Manouchehr (Supervisor)
Abstract
There is increasing evidence that injecting modified brines has a significant impact on the amount of oil recovered, but the exact mechanism by which this occurs is an unsettled issue, and is supposed to be a cause of the complex interactions occurring between the phases insitu. In this thesis, surface chemistry of smart water has been investigated. Fluid/solid and fluid/fluid interactions for Bangestan crude oil in tfhe presence of designed solutions and a set of dilutions of Persian Gulf seawater have been studied and compared. Fluid/solid interactions were investigated through wettability studies. Impact of salinity and ionic composition on this interaction was measured through contact...
Evaluation of Microstructure and Wear Behaviour of Nicrbsi Composite Coating Deposited by Atmospheric Plasma Spray and Plasma Transferred Arc on Steel Substrate
, M.Sc. Thesis Sharif University of Technology ; Movahedi, Mojtaba (Supervisor) ; Kokabi, Amir Hossein (Supervisor)
Abstract
Nowadays, in many industrial applications, protecting surfaces has become necessary. This research attempted to create a coating resistant to the wear of NiCrBSi with the help of the atmospheric plasma spray and the process of plasma Transferred Arc on the substrate of the simple carbon steel. Also, in order to study the effect of compositing on hardness and abrasive properties of the APS coatings, NiCrBSi powder was strengthened with 25 weight percent of Titanium Carbide particles so that the NiCrBSi-25TiC composite coating could also be created. According to the nature of the APS process, the substructure of this coating always has some porosity and layered structure, and the connection of...
Wettability alteration in carbonates during "Smart Waterflood": Underling mechanisms and the effect of individual ions
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 487 , 2015 , Pages 142-153 ; 09277757 (ISSN) ; Mousapour, M. S ; Ayatollahi, S ; Vossoughi, M ; Beigy, A. H ; Sharif University of Technology
Elsevier
2015
Abstract
There are increasing evidences that adjusting the chemistry of the injecting water improves the oil recovery efficiency. However, the underlying mechanisms for this technique which is referred to as "smart waterflood" have not yet been thoroughly understood. It is needed to explore the role of individual ions through set of different tests, to find the right mechanisms behind "smart waterflood". This study is focused on the fluid/solid (carbonate) interactions through systematic wettability measurement. Contact angle measurements accompanied by spontaneous imbibition tests were employed to determine the role of individual monovalent and divalent ions in wettability alteration process by...
The influence of annealing temperature on the graphitisation of CK 45 steel
, Article Journal of Alloys and Compounds ; Volume 475, Issue 1-2 , 2009 , Pages 822-826 ; 09258388 (ISSN) ; Issa Abadi Bozchalooi, G ; Azzat pour, H. R ; Sharif University of Technology
2009
Abstract
Graphitization in steels is a subject which has been studied temporarily in past decades. The importance of this phenomenon is due to the fact that graphite formation in steels can ease machining treatment and increase cold-work capability of steels. Weight reduction of the parts and the dedicated bioenvironmental properties of these steels are considered as a valuable replacement for lead containing steels for researchers. Anyway there has been always the assumption that this operation is long and not economically cost effective. For this reason due to the different conditions of applied heat treatments, the effects of the temperature and the time period of heat treatment on the...