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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...
Role of Affective Commitment in the Relationship between Ostracism and Turnover Intention
, M.Sc. Thesis Sharif University of Technology ; Banki, Sara (Supervisor)
Abstract
A lot of researchers have suggested that ostracism as a disruptive behavior, has been widespread among organizations and a lot of researches has been studied its consequences in recent years.This research studies ostracism’s consequences and proposes a theoretical model of organizational ostracism with affective commitment, intention to turnover and organizational dependability as one of affective commitment’s antecedents. This study has been done on 231 employees of three medium knowledge-based organizations to identify the effects of ostracism on employee’s turnover behavior. Results show that ostracism, due to its impact on the affective commitment of ostracized peoples, reduces this type...
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...
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...
Identifying Active Followership Behaviors in Interaction with Managers with Autocratic Leadership Style in an Iranian Organization
, M.Sc. Thesis Sharif University of Technology ; Alavi, Babak (Supervisor) ; Banki, Sara (Supervisor)
Abstract
Purpose: The purpose of this thesis was to identify active followership behaviors of followers in interaction with autocratic leaders. An active follower thinks critically and takes initiatives.
Design: Given that Followership literature is still in its infancy, the research questions needed a qualitative approach, in this case grounded theory. In total, 19 top- & middle-level managers were interviewed as leaders and followers, accordingly, using semi-structured interviews.
Findings: 4 categories of active followership were found, each having 3-4 specific behaviors. These categories are: precautionary behaviors, facilitating behaviors, modificating behaviors, and consolidating...
Design: Given that Followership literature is still in its infancy, the research questions needed a qualitative approach, in this case grounded theory. In total, 19 top- & middle-level managers were interviewed as leaders and followers, accordingly, using semi-structured interviews.
Findings: 4 categories of active followership were found, each having 3-4 specific behaviors. These categories are: precautionary behaviors, facilitating behaviors, modificating behaviors, and consolidating...
An Investigation of the Mediating role of Organizational Cynicism on the Relations between the Politics Perception and Organizational Commitment
, M.Sc. Thesis Sharif University of Technology ; Alavi, Babak (Supervisor) ; Banki, Sara (Supervisor)
Abstract
There is no consensus definition of cynicism in literature. In this research different definitions of cynicism have been investigated and two concept of organizational cynicism and trait cynicism have been taken into consideration. Organizational cynicism is a negative attitude that is prevalent in employees. In literature some antecedents and consequences of organizational cynicism have been suggested. It seems organizational cynicism can be investigated in a more complex relations. The focus of this research is on the mediating role of organizational cynicism on the likely relations between politics perception and organizational commitment. That is to say organizational cynicism can...
The Influence of Authentic Leadership on the Relationship between Transformational Leadership, and Feedback-seeking Behaviors
, M.Sc. Thesis Sharif University of Technology ; Alavi, Babak (Supervisor) ; Banki, Sara (Supervisor)
Abstract
Feedback-seeking behavior is the effort of employees to get feedback from the environment and around people about their performance. One of the research questions in this field is about the factors that increase this behavior in the staff. Transformational leadership as a leadership style, stimulates, and motivates followers to achieving desirable operational results. In addition, an important consequence of this style could be increasing the followers' capabilities. Transformational leaders are trying to empower their followers to build and empower them, which can provide a strong incentive for employees to move and grow, which may encourage them to have a better performance. One of...
Applying Gamification in Corporate Entrepreneurship Culture, Specially Missionary Organizations; Through SafirFilm Case Study
, M.Sc. Thesis Sharif University of Technology ; Yavari, Elham (Supervisor) ; Banki, Sara ($item.subfieldsMap.e)
Abstract
Although existing literature on organizational culture and its change process contains meaningful and rich theories but our studies show that there is no perfect and detailed framework on linking organizational culture change and corporate entrepreneurship culture. In addition to that, Gamification –defined as taking the game design elements into non-game contexts– is a fruitful and academically rich research area. Fortunately an idea proposed recently to explain a method for enhancements in organizational culture in general, and in corporate entrepreneurship culture in particularby Yavari and Jafarian based on using game mechanisms. In their paper "A Gamification-Based Method for Corporate...
Synthesis of Tin and Ti2n Nanostructured Coatings on Ti alloys Using Magnetron Sputtering System And Comparison of Their Biocompatibility Properties
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor) ; Khamse, Sara (Supervisor)
Abstract
Considering the importance of biocompatibility of implantable prothesis’, metallic alloys have weaker corrosion resistance than ceramics. In order to extend usage of nanomaterials to improve the bio-properties of materials, Nano-structured ceramic coatings are being suggested to improve corrosion resistance and biocompatibility of prosthesis. Meanwhile, very good properties of TiN, such as corrosion resistance and mechanical properties as a thin film coating are undeniable. In this study, TiN and Ti2N thin film were deposited on Ti-based substrate, using PVD and Magnetron sputtering at different argon to nitrogen ratio. The crystal structure of the films was examined using Grazing XRD...
The Instructional Effect of Dynamic-assessment, Non-dynamic Traditional Assesment, and Non-assessment Courses on Iranian EFL Learners' Interlanguage Pragmatic Production
, M.Sc. Thesis Sharif University of Technology ; Tajeddin, Zia (Supervisor) ; Alemi, Minoo (Supervisor)
Abstract
There are several methods proposed for the instruction and assessment of interlanguage pragmatic competence of foreign language learners. Dynamic assessment as one of the recent methods arising from Vygotsky’s sociocultural theory of mind incorporates assessment and instruction by engaging learners in a process of interaction with the mediator while the learners are trying to perform a challenging task. The present study aimed to explore the advantage of Dynamic Assessment as an instructional instrument over the Non-dynamic (traditional) Assessment and Non-assessment approaches and their effects on the Iranian intermediate level students. The target speech acts of apology, complaint, and...
Monitoring of Structure Characteristics, Humidity, Temperature and Torsion Using Optical Fiber Sensor
, Ph.D. Dissertation Sharif University of Technology ; Bahrampour, Alireza (Supervisor) ; Tofighi, Sara (Supervisor)
Abstract
Fiber optic sensors have found industrial applications due to their unique characteristics and wide range of environmental parameters. Specifically, distributed optical fiber sensors which have applications in borders protection, intrusion detection, oil and gas leakage detection and smart irrigation of farms and gardens, have attracted significant attention from research groups around the world in recent years. According to the forecasts, among all kind of optical fiber sensors, the temperature and acoustic/vibration sensors will seize the market during the coming years. In this thesis, three kind of optical fiber sensors are proposed for environment health monitoring. First, distributed...