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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...
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...
Algebraic Topology Metheds on Graph Coloring
, M.Sc. Thesis Sharif University of Technology ; Jafari, Amir (Supervisor)
Abstract
The aim of this thesis is to introduce some algebraic topologies methods and apply them on fining the chromatic number of some famous graphs and also hypergraphs. In the first part, we will use a mixture of two well-known technics, Tucker lemma and Discrete Morse theory to find an upper bound for the chromatic number of s-stable Kneser for some specific vector s. to find the sharper upper bound, we will deviate our strategy and use another approach by finding an edge-labeling and apply some theorems in POSET algebraic topology. In this way, we also find a connection between Young diagrams and the numbers of spheres in the box complex related to Kneser graphs and hypergraph. Actually, we can...
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...
Performance Assessment of PEM Fuel Cell in Extreme Conditions (Sub- Freezing Temperatures)
, M.Sc. Thesis Sharif University of Technology ; Rajabi Qhahnuyeh, Abbas (Supervisor) ; Ahmadi, Pouria (Supervisor)
Abstract
Fossil fuels provide the most needs of the world's energy, however, continues to lead to two key problems. The first problem is their limitation, and the second problem is the creation of serious environmental issues. Therefore, the need for renewable energy sources is felt more than ever.As an energy source, hydrogen is the lightest, most efficient and cleanest fuel. One of its unique properties is efficiency, the production of electricity by fuel cells through the electrochemical process, has far greater efficiency than of mechanical energy production from fossil fuels in internal combustion engines or energy production in thermal power plants. A fuel cell is a device that converts...
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...
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...