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nozari--hadi
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Total 201 records
Experimental Study of Flame Stability on a Reheat System
, M.Sc. Thesis Sharif University of Technology ; Farshchi, Mohammad (Supervisor)
Abstract
In conventional afterburning systems, the burnt products of the primary combustion enter the afterburning zone, where the fuel is injected and the mixture is ignited to form a flame which is stabilized by a flameholder.
The present experimental study focuses on concepts of afterburning and flame stability in a reheat system. For this purpose an afterburner setup is designed and manufactured. The setup comprises of two main regions; the preheating region and the reheat zone. Fuel used in preheater is LPG while jet fuel is injected in reheat zone. Through the tests the key parameters which are adjusted to be in similar ranges as the conventional afterburners are the oxygen amount of the...
The present experimental study focuses on concepts of afterburning and flame stability in a reheat system. For this purpose an afterburner setup is designed and manufactured. The setup comprises of two main regions; the preheating region and the reheat zone. Fuel used in preheater is LPG while jet fuel is injected in reheat zone. Through the tests the key parameters which are adjusted to be in similar ranges as the conventional afterburners are the oxygen amount of the...
Experimental Study on Erosion Control at Channel Junctions with Submerged Vanes
, M.Sc. Thesis Sharif University of Technology ; Jamali, Mirmosaddegh (Supervisor)
Abstract
In this study, the effect of submerged vanes on the bed erosion pattern at a 90° open-channel junction has been evaluated experimentally. In this study, 41 tests have been conducted in four different steps. In each test, the bed surface level has been measured at the end of 1st, 2nd and 24th hour. In the first step, the preliminary tests have been conducted. In this step, six different formations of submerged vanes have been selected and their performance has been evaluated and the most efficient formation, in the field of maximum scour depth reduction, has been selected. In the second step, six different formations of submerged vanes have been selected and their performance has been...
Stake Size Effect on Guilt Aversion in Psychological Games Master Thesis
,
M.Sc. Thesis
Sharif University of Technology
;
Talebian, Masoud
(Supervisor)
Abstract
Guilt aversion, the process of avoiding guilt, when guilt indicates the human sense which is present when they let down other's expectations. As the definition suggests, guilt is related to what one thinks of the others’ thoughts; i.e. the second-order beliefs. Incomplete information models of guilt aversion are the most reliable ones in the literature due to economic experiments. Based on these models, the dictator game and the trust game are applied to measure the degree of guilt aversion. In both the above psychological games, there are two players where Player A has the power to decide about the split of the money. We use the amount of transferred money to Player B is as a sign of guilt...
Dynamics of null hypersurfaces in general relativity
, Article General Relativity and Gravitation ; Volume 34, Issue 2 , 2002 , Pages 243-253 ; 00017701 (ISSN) ; Mansouri, R ; Sharif University of Technology
2002
Abstract
This paper shows how the structure and dynamics of a lightlike thin shell in general relativity can be obtained from a distributional approach
The methods of gluing manifolds in general relativity
, Article Journal of Mathematical Physics ; Volume 43, Issue 3 , 2002 , Pages 1519-1535 ; 00222488 (ISSN) ; Mansouri, R ; Sharif University of Technology
2002
Abstract
Some areas of modern theoretical physics such as modern cosmology contain different manifolds which must be glued together along a common boundary. These boundaries can be spacelike, timelike, or lightlike hypersurfaces. This paper shows how this gluing for different hypersurfaces is possible. Two different approaches are considered and the extent to which these approaches are equivalent are discussed. In particular, we will construct a distributional approach for dynamics of lightlike hypersurfaces in general relativity. Since Einstein's equations are nonlinear PDEs, for discontinuous metrics such as signature changing metrics, product of distributions are unavoidable. To glue two different...
Optimization of Xylitol Production
, M.Sc. Thesis Sharif University of Technology ; Alemzade, Iran (Supervisor)
Abstract
Xylitol is a sugar alcohol or polyol that has been used as a food additive and sweetening agent due to Its high sweetening power, anti-cariogenic properties and possibilities for use in diabetic food products, makes xylitol an attractive sucrose substitute in a wide variety of foods and beverages. Xylitol is a five carbon polyol or pentitol obtained by the hydrogenation of xylose. xylitol could be produced from xylose in rice seed coats medium by Saccharomyces cerevisiae. For xylitol production, S.cerevisiae was grown in preculture medium at 30°C and agitated at 120 rpm on a rotary platform shaker. The cells were harvested after 20hr, were centrifuged and transferred to the production...
Kinetic Study of Selective Catalytic Reduction of over a Cu/Zeolite Catalyst for Emission Control from Diesel Engines
, M.Sc. Thesis Sharif University of Technology ; Hamzehlouyan, Tayebeh (Supervisor)
Abstract
Urban air pollution has become a significant environmental concern in recent times. NOx recognized as a criterion pollutant, is especially problematic. In 2021, the Tehran Air Quality Control Company reported that the ambient concentration of NOx in Tehran was around 50 ppb, which surpasses both the initial and final targets recently established by the World Health Organization (40 ppb and 10 ppb, respectively). To control and predict NOx emissions from diesel engines, A detailed selective catalytic reduction (SCR) model has been developed to describe the global kinetic reactions within the catalyst. This model incorporates two types of sites for high- and low-temperature NH3...
Study of the Effect of Presence of Nano- Particles on the Mass Transfer and Hydrodynamics of Drops
, M.Sc. Thesis Sharif University of Technology ; Bastani, Daruoosh (Supervisor) ; Goodarznia, Iraj (Supervisor)
Abstract
Regarding to the effect of nanoparticles on mass transfer and hydrodynamics characteristics, limited number of studiesavailableinthe literature.In this work, mass transfer performanceand hydrodynamic characteristics nanofluidshavebeeninvestigated in the liquid−liquid extraction process. The chemical system of toluene-acetic acid-water was used, and two Extraction columnswith diameter of 10cm and height of 55cm and 6 cm were designed. The drops were organic nanofluids containing silica nano-particles and carbon nano-tubes.Synthesized silica nanoparticles by sol-gel methods, were modified with Triethoxyoctylsilane and Polydimethylsiloxane as well as Carbon nano-tubes were modified with dodecyl...
Collision-free path planning of a novel reconfigurable mobile parallel mechanism
, Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 231, Issue 20 , 2017 , Pages 3728-3742 ; 09544062 (ISSN) ; Tale Masouleh, M ; Kazemi, H ; Sharif University of Technology
2017
Abstract
This paper initially deals with the design of a new customized reconfigurable mobile parallel mechanism. This mechanism is called the 'Taar Reconfigurable ParaMobile' (TRPM), consisting of three mobile robots as the main actuators. Then, the kinematics and path planning for this mechanism are presented. The newly proposed mechanism is expected to circumvent some shortcomings of inspection operation in unknown environments with unexpected changes in their workspace, for example, in a water pipe with a non-uniform cross-sectional area. In this paper, 'Artificial Potential Field' (APF) has been assumed to be the path planning algorithm and its resulting attractive and repulsive forces are only...
Introduction and Analysis of Energy Index to Evaluate Arm Motion Quality in Neuromuscular Patients
, M.Sc. Thesis Sharif University of Technology ; Behzadipour, Saeed (Supervisor) ; Hoviattalab, Maryam (Supervisor)
Abstract
Quantitative motion quality evaluation has been always of much significance for CVA patients, especially the HCP ones. The purpose of the present study is to introduce and analyze the efficiency of a novel index, namely “Consumed Energy Index”, for evaluating the quality of the motions performed by HCP patients. For this purpose, Firstly, a Musculo-Skeletal model of the human arm was provided on Matlab and OpenSim softwares, with four DoFs: three DoFs at shoulder and one DoF at elbow joint as well as eight muscles. The muscles are in pairs of flexor-extensor at each DoF. The model is capable of receiving Cartesian trajectories for joints and solving inverse kinematics and dynamics to obtain...
Aeroelastic Analysis of Horizontal Axis Wind Turbine Based on Actuator Disk Method
, M.Sc. Thesis Sharif University of Technology ; Ebrahimi, Abbas (Supervisor) ; Rezaei, Mohammad Mahdi (Co-Advisor)
Abstract
The issue of solid and fluid interaction in horizontal axis wind turbines with diameter of more than 120 meters is one of the most important researching subjects of this type of turbines. This issues needs quick and exact solutions because of the high computational cost of fluid and structural domains.In this research a quick method with acceptable accuracy has been suggested which is based on computational fluid dynamic to examine the aeroelastic behavior of rotor and wind turbine tower. The actuator disc method in two domains of axisymmetric and three-dimensional has been used to compute aerodynamic forces. For this purpose a code has been written in C++ to set down virtual momentum on...
Advances in heuristic signal processing and applications
, Book ; Chatterjee, Amitava ; Nobahari, Hadi ; Siarry, Patrick
Springer
2013
Abstract
There have been significant developments in the design and application of algorithms for both one-dimensional signal processing and multidimensional signal processing, namely image and video processing, with the recent focus changing from a step-by-step procedure of designing the algorithm first and following up with in-depth analysis and performance improvement to instead applying heuristic-based methods to solve signal-processing problems. In this book the contributing authors demonstrate both general-purpose algorithms and those aimed at solving specialized application problems, with a special emphasis on heuristic iterative optimization methods employing modern evolutionary and swarm...
Collision-free path planning of a novel reconfigurable mobile parallel mechanism
, Article International Conference on Robotics and Mechatronics, ICROM 2015, 7 October 2015 through 9 October 2015 ; 2015 , Pages 389-394 ; 9781467372343 (ISBN) ; Kazemi, H ; Masouleh, M. T ; Novin, R. S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
This paper initially deals with the design of a new customized reconfigurable mobile parallel mechanism. This mechanism is called "Taar Reconfigurable ParaMobile (TRPM)", consisting of three mobile robots as the main actuators. Then, the kinematics and path planning for this mechanism are represented. The newly proposed mechanism is expected to circumvent some shortcomings of inspection operation in unknown environments with unexpected changes in their workspace, e.g., in a water pipe with non-uniform section area. In this paper, "Artificial Potential Field (APF)" has been assumed to be the path planning algorithm and its resulting attractive and repulsive forces are only applied to the...
Parallel Multi-disciplinary Design Optimization of a Guided Flying Vehicle
, M.Sc. Thesis Sharif University of Technology ; Nobahari, Hadi (Supervisor)
Abstract
Multi-disciplinary design optimization (MDO) of a surface to air flying vehicle has been done in this research, on the basis of flight simulation. The MDO problem have five disciplines consists of aerodynamic, propulsion, guidance, control, and fire control. Multiple campaign scenarios are defined. The MDO problem has 31 design variables and two objective functions. The objective functions are flying vehicle weight and miss distance. A new meta-heuristic algorithm has been designed to solve multi-objective optimization problems. The new algorithm has been called Multi-objective Adaptive Real-coded Memetic Algorithm (MARCOMA). The MARCOMA can solve large-scale and multi-objective problems and...
Synthesis and Characterization of PVDF Magnetic Nanocomposite
, M.Sc. Thesis Sharif University of Technology ; Forounchi, Massoud (Supervisor)
Abstract
PVDF (polyvinylidene fluoride) magnetic nanocomposite films were prepared by solution casting using two types of nanomagnetic particles: (i) magnetic nanoparticles synthesized by using an alkaline solution of mixed ferrous/ferric salts along with oleic acid as a coating agent at 70˚C; (ii) Fe3O4 nanoparticles prepared by hydrolysis of aqueous solution of ferrous/ferric salts with potassium hydroxide at room temprature. Scanning electron microscopy (SEM) showed that the PVDF magnetic nanocomposite had a porous structure with Fe3O4 nanoparticles dispersed inside the porous polymer matrix. The presence of crystalline magnetite within the polymer matrix was confirmed by X-Ray diffraction method...
Optimal Design and Real-time Implementation of a Cooperative Guidance Algorithm against a Flying Vehicle
, M.Sc. Thesis Sharif University of Technology ; Nobahari, Hadi (Supervisor)
Abstract
A cooperative aerial system to defense a Ground Station (GS), against an Incoming aerial Targets (IT) is presented. GS is surrounded by given terrains and a group of homogenous Unmanned Aerial Vehicles (UAVs) are employed using a novel online guidance algorithm in a decentralized manner. The proposed algorithm includes loiter, midcourse and terminal phases. During loiter; UAVs follow an optimal circular path. IT is supposed to approach GS along an optimal low altitude trajectory with respect to the terrains. UAVs are informed the initial position and velocity of IT and they are unaware of IT trajectory. Each UAV decides on whether to engage with IT or not, and shares its decision with other...
Development of an Evolutionary Algorithm Based on Surrogate Models to be used in Multi-disciplinary Design Optimization of a Flying Vehicle
, M.Sc. Thesis Sharif University of Technology ; Nobahari, Hadi (Supervisor)
Abstract
In this research, multi-disciplinary design optimization (MDO) of a flying vehicle has been done based on the flight simulation. A meta-heuristic algorithm called Multi-objective Adaptive Real-coded Memetic Algorithm (MARCOMA) has been used for optimization. Since solving a MDO problem is a time consuming process, a RBF neural network has been used in the optimization algorithm as a surrogate model. The new algorithm, called MARCOMA+NN, has been tested with some standard benchmarks. MDO problem has six disciplines consists structure, aerodynamic, propulsion, guidance, control, and fire control. The MDO problem has 31 design variables and two objective functions. The objective functions are...
Cooperative Search and Localization of Aerial Targets, Using a Group of Fixed Wing UAVs
, M.Sc. Thesis Sharif University of Technology ; Nobahari, Hadi (Supervisor)
Abstract
Topic that is investigated in this article include identify and localization a number of aerial target penetrating into a protected by area by a swarm of UAVs is fixed wing. UAVs do not have any prior notice of positioning targets. In addition, it is assumed that lacks any radiation exploitable targets and thus use UAVs for Targets Detection from an active radar system. Obviously this article focus on developing a guidance algorithm UAVs to this particular issue and also as the targets participatory is localization algorithm. In addition, extraction type and performance characteristics radar system required and also performance characteristics of the class of UAVs, which is suitable to...
Cooperative Search and Localization of Mobile RF Ground Targets, Using a Group of UAVs
, M.Sc. Thesis Sharif University of Technology ; Nobahari, Hadi (Supervisor)
Abstract
In this project, a method for cooperative search and localization of RF ground moving targets by a group of UAVs is developed. It should be noted that UAVs are just equipped with GPS and directional sensors. Since there is fuel constraint for UAVs, they take fuel from a tanker whenever they require. Moreover, searching method enables the UAVs to see different parts of the desired area with almost uniform distribution. In addition, the proposed approach enables the UAVs to perform a local search with the aim of finding the targets having lost their signal during localization mode. Finally, based upon a fueling decision function the UAVs take turn, approach to the fuel tanker, and start...
Development of Integrated Model of the Wastewater and Organic Solid Waste Flows to Minimize Environmental Impacts and Maximize Energy Recovery for a Residential Building
, M.Sc. Thesis Sharif University of Technology ; Avami, Akram (Supervisor)
Abstract
Nowdays much of the organic solid waste and wastewater is buried using centralized and traditional methods. This leads to many problems, including groundwater pollution, methane emissions into the atmosphere and rapid transmission of disease. In order to avoid these problems, using a decentralized approach can be a good solution. In this study, recovery of organic waste and wastewater of residential buildings using anaerobic digester as a decentralized way, have been examined. Using experiments, the optimum mass ratio of organic solid waste and wastewater is obtained as 80% and 20% respectively. Biogas production model is developed using mass balance and Balance of electrons in redox...