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sadeghi-bughar--babak
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The Effect of Rudder Angle on Ship’s Fuel Consumption
, M.Sc. Thesis Sharif University of Technology ; Khorasanchi, Mahdi (Supervisor) ; Zare, Arman (Co-Supervisor)
Abstract
The aim of this research is to investigate the effect of speed and direction of current on ship fuel consumption. A KCS benchmark model has been numerically studied in calm water and fourteen current and wind conditions with the same speed and different directions to determine how the ship performance is dependent on flow conditions. The model has been simulated in an artificial basin propelled by a single right-handed propeller via a CFD commercial code. Numerical results revealed a linear relationship between the deviation of current and wind from head-sea or following-sea conditions and the rudder angle. The head-sea and following-sea currents and winds increased and decreased the lateral...
Simulation of wetting tendency of fluids with high density ratios using RK Lattice Boltzmann method
, Article 16th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2019, 14 October 2019 through 18 October 2019 ; 2020 ; Pak, A ; Sadeghi, H ; Sharif University of Technology
Asian Regional Conference on Soil Mechanics and Geotechnical Engineering
2020
Abstract
Several lattice Boltzmann models for multi-phase flow have been developed, but few of them are capable of modeling fluid flows with high density ratio in the order of 1000. Therefore, an advanced chromodynamics, Rothmann-Keller (RK) type model is employed in current study, which can handle liquid-gas density ratio in the order of 1000 and viscosity ratio in the order of 100. Other distinctive characteristics of the proposed model are high stability, and capability of setting parameters such as surface tension independently. In spite of these benefits, the original RK model fails to model wetting tendency of the fluids. As a result, it is impossible to correctly simulate two-fluid phase flow...
Mechanical behavior during aging of plastically deformed AA6061-SiCp composite in different temperatures
, Article Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications ; Volume 226, Issue 4 , 2012 , Pages 322-329 ; 14644207 (ISSN) ; Serajzadeh, S
SAGE
2012
Abstract
In this study, the kinetics of aging in AA6061 and AA6061 with 5% volume fraction SiCp were studied and compared. The composite was first produced and homogenized using stir casting technique followed by hot extrusion with the ratio of 18:1. Then, both AA6061 and the composite were aged at three different temperatures including room temperature, 170 °C and 240 °C, while mechanical properties during aging were evaluated employing hardness measurements and tensile testing. Moreover, in order to assess the effect of plastic deformation on the kinetics of aging, a series of samples were first deformed by equal-channel angular pressing immediately after solution treatment and then aged in the...
Electroosmotic flow and ionic conductance in a pH-regulated rectangular nanochannel
, Article Physics of Fluids ; Volume 29, Issue 6 , 2017 ; 10706631 (ISSN) ; Saidi, M. H ; Sadeghi, A ; Sharif University of Technology
2017
Abstract
Infinite series solutions are obtained for electrical potential, electroosmotic velocity, ionic conductance, and surface physicochemical properties of long pH-regulated rectangular nanochannels of low surface potential utilizing the double finite Fourier transform method. Closed form expressions are also obtained for channels of large height to width ratio for which the depthwise variations vanish. Neglecting the Stern layer impact, the effects of EDL (Electric Double Layer) overlap, multiple ionic species, and association/dissociation reactions on the surface are all taken into account. Moreover, finite-element-based numerical simulations are conducted to account for the end effects as well...
Geotechnical characterization and collapsibility of a natural dispersive loess
, Article Engineering Geology ; Volume 250 , 2019 , Pages 89-100 ; 00137952 (ISSN) ; Kiani, M ; Sadeghi, M ; Jafarzadeh, F ; Sharif University of Technology
Elsevier B.V
2019
Abstract
During preliminary investigation phase of the national Chabahar-Zahedan railway line, serious geotechnical problems including non-uniform settlements, tensile cracks, and local collapse were reported in parts of the path near the coastline. A follow-up field investigation revealed that the in-situ soil at construction site has a metastable structure being sensitive to saturation and loading. Therefore, a comprehensive series of physical, chemical, electro-chemical, and geotechnical tests were conducted to classify and characterize the soil properties and behavior in its natural state. The natural soil was classified as a clayey loess with moderately dispersive to dispersive characteristics....
Geometry effect on electrokinetic flow and ionic conductance in pH-regulated nanochannels
, Article Physics of Fluids ; Volume 29, Issue 12 , 2017 ; 10706631 (ISSN) ; Saidi, M. H ; Moosavi, A ; Sadeghi, A ; Sharif University of Technology
2017
Abstract
Semi-analytical solutions are obtained for the electrical potential, electroosmotic velocity, ionic conductance, and surface physicochemical properties associated with long pH-regulated nanochannels of arbitrary but constant cross-sectional area. The effects of electric double layer overlap, multiple ionic species, and surface association/dissociation reactions are all taken into account, assuming low surface potentials. The method of analysis includes series solutions which the pertinent coefficients are obtained by applying the wall boundary conditions using either of the least-squares or point matching techniques. Although the procedure is general enough to be applied to almost any...
Unsteady solute dispersion by electrokinetic flow in a polyelectrolyte layer-grafted rectangular microchannel with wall absorption
, Article Journal of Fluid Mechanics ; Volume 887 , 2020 ; Saidi, M. H ; Moosavi, A ; Sadeghi, A ; Sharif University of Technology
Cambridge University Press
2020
Abstract
The dispersion of a neutral solute band by electrokinetic flow in polyelectrolyte layer (PEL)-grafted rectangular/slit microchannels is theoretically studied. The flow is assumed to be both steady and fully developed and a first-order irreversible reaction is considered at the wall to account for probable surface adsorption of solutes. Considering low electric potentials, analytical solutions are obtained for electric potential, fluid velocity and solute concentration. Special solutions are also obtained for the case without wall adsorption. To track the dispersion properties of the solute band, the generalized dispersion model is adopted by considering the exchange, the convection and the...
Dispersivity, collapsibility and microstructure of a natural dispersive loess from Iran
, Article 16th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2019, 14 October 2019 through 18 October 2019 ; 2020 ; Nasiri, H ; Panahi, P. A ; Sadeghi, M ; Sharif University of Technology
Asian Regional Conference on Soil Mechanics and Geotechnical Engineering
2020
Abstract
A new type of collapsible soil was encountered in Southern Iran and caused some serious technical problems including subsidence, collapse and sinkholes during the construction of Zahedan-Chabahar railway. Field observations indicated that in-situ soil contains excessive amount of salts resulting in dispersive features in response to seepage forces in addition to its collapsibility. Therefore, a systematic research plan including field sampling and laboratory testing was carried out to investigate the observed geotechnical features. Results of physio-chemical tests revealed the dominance of Sodium in excess of 70% relative to total dissolved salts, which results in high dispersive potential....
Self-Leadership Strategies in Teamwork and Share Leadership Orientation with the Mediating Effect of Self-Efficacy
, M.Sc. Thesis Sharif University of Technology ; Alavi, Babak (Supervisor)
Abstract
The main purpose of this study is to evaluate the linkage between two constructs about teamwork activities. One of them is "self-leadership in teamwork", the extent to which a person could control and manage his thoughts and activities in teamwork. The other is "shared leadership orientation", which is about orientation of people to contribute in leadership processes. This linkage evaluated with consideration of "self-efficacy in shared leadership" as a moderator.
Questionnaires of self-leadership in teamwork and self-efficacy in shared leadership elicited from literature with a little change and shared leadership questionnaire developed in another study by the author.Questionnaires...
Questionnaires of self-leadership in teamwork and self-efficacy in shared leadership elicited from literature with a little change and shared leadership questionnaire developed in another study by the author.Questionnaires...
The Hidden Side of Coin: What Self Leadership Strategies Are Applied by Successful Iranian Women Entrepreneurs?
, M.Sc. Thesis Sharif University of Technology ; Alavi, Babak (Supervisor)
Abstract
Women are going to play more important roles in the economy of most countries including Iran. Hence, since the number of entrepreneurs among women is increasing, identifying characteristics and other factors that cause these group to be successful, is a critical issue. Studies show that entrepreneurs, especially women entrepreneurs, face numerous problems in their career. These problems are especially more demanding in societies with unique cultural attributes. Therefore, applying personal and managerial solutions in order to overcome these problems are necessary. On the other hand, researchers believe that one of the most effective and beneficial concepts helping entrepreneurs in their...
Identifying the Ethical Dilemmas Confronting Human Resource Managers of Iranian Project Based Companies and Exploring their Causes
, M.Sc. Thesis Sharif University of Technology ; Alavi, Babak (Supervisor)
Abstract
The present study was performed aiming to identify the ethical dilemmas human resource managers confront with in Iranian project-based organizations as well as to trace out the underlying causes. “Ethical dilemma” refers to a decision making situation in which ethical considerations render all the alternatives inapt, thence making the decision making process ethically complex. First of all, a theoretical framework was developed based on the preceding research; then, the study was further conducted utilizing a qualitative research method with an exploratory approach. The data were collected using in-depth interviews and analysed using the theme analysis method. The corresponding interviewees...
Multiple Case Study of Distributed Leadership Effectiveness in Educational Major FoundingTeams of Sharif University of Technology
,
M.Sc. Thesis
Sharif University of Technology
;
Alavi, Babak
(Supervisor)
Abstract
Using Distributed leadership framework while studying the leadership phenomena in teams, especially in educational environment, has received more attention by scholars in these years. Although the results of these researches indicated positive consequences mostly, the need for exploratory studies to identify situational and contextual factors in distributed leadership effectiveness has been mentioned. In other words, it has been suggested that the effectiveness of distributed leadership in teams may be affected by situational and contextual factors. In the current multiple case study, after the initial study of leadership and its functions in some schools of Sharif University of Technology,...
Identification of Influence Mechanisms of Executive/non-executive Board Composition on Board’s Attribution Style
, M.Sc. Thesis Sharif University of Technology ; Alavi, Babak (Supervisor)
Abstract
The influence mechanisms of executive/non-executive board compostion on board’s attribution style have been explored. In two case studies, I have examined boards’ causal interpretation about a critical incident which had a significant impact on firm performance. A qualitative research approach has been taken in the case studies. Data was gathered through semi-structured interviews with all board members and was analyzied with the theme analysis method. According to the results, board of directors’ collective attribution formation process can be devided into three stages of members’ expression of information and facts at board meetings, forming the individual judgements of members and at...
A Study on Relationships between Career Anchors and Career Orientations
, M.Sc. Thesis Sharif University of Technology ; Alavi, Babak (Supervisor)
Abstract
Career Orientations or career choices, can be affected by internal and external factors. External factors are the environmental conditions that the reward and the attractiveness of selecting a career choice are dependent to them. Internal factors include the needs of oneself from his/her job, his/her beliefs and his/her skills and competencies about the job. In this research the internal antecedents of managerial and technical orientations between programmers have been identified. On the other hand the perception of people about the compensation system as an external factor which can affect the mentioned relationships, have been analyzed. It seems that this is the first research which career...
The Evaluation of Application of Unfolding Model of Turnover to Explain the Turnover of Knowledge Workers in Some Iranian Software Companies
,
M.Sc. Thesis
Sharif University of Technology
;
Alavi, Babak
(Supervisor)
Abstract
Voluntary turnover has direct and indirect expenses for organizations and for this purpose; it has one of the richest literatures in academic works. Due to the especial role of knowledge workers in organizations, these expenses in knowledge-based organizations are more important and more costly than that of other organizations. One of the latest theories in the field of voluntarily turnover was introduced by Lee and Mitchell (1994) that was named “Unfolding Model of Turnover” to describe the process of decision of voluntary turnover. This theory is distinguished from its similar theories from two main aspects: First, they introduced new elements like shock. Second, they introduced...
, M.Sc. Thesis Sharif University of Technology ; Alavi, Babak (Supervisor)
Abstract
The measure of success in a company is determined by a high performing workforce that demonstrates the competencies necessary to drive the business success, while meeting the organization's strategic goals. This is where competency-based human resource management becomes important. The main factor contributing to the above noted area is the identification of core competencies. There has been a lot of research in this area during the past few years. Each research demonstrates an approach for the development of critical human resource competency models in an organization. In order to determine the foregoing competency model, the early studies in this area have been focused on the distinction...
Investigating the Components Affecting the Perception Of the Authenticity of Senior Managers of Knowledge-Based Companies in the Instagram Social Network and Its Role in Shaping the Organization's Employer Brand from the Perspective of Potential Knowledge Employees
, M.Sc. Thesis Sharif University of Technology ; Alavi, Babak (Supervisor)
Abstract
The goal of this study was to realize how the younger generation's perceptions of the authenticity of senior managers in knowledge-based firms affects the components of their employer brand on social media. For this reason, the perceptions of managers' authenticity from the perspective of the younger generation on Instagram, as an example of social networks, was investigated in the first stage of the study. The mechanisms of effectiveness of the identified components of authenticity are sought in the second step, in shaping the components of the manager's organization's employer brand. To attain the research goal, an exploratory approach was taken conducted, and a qualitative research method...
Possible Impacts of Telework Initiated by COVID-19 Outbreak on Teleworkers’ Psychological Well-being: A Qualitative Study
, M.Sc. Thesis Sharif University of Technology ; Alavi, Babak (Supervisor)
Abstract
This research explores the impacts of the telework initiated by the outbreak of COVID-19, which is being called “emergent telework” in this research, on psychological well-being of teleworkers. As for the nature of emergent telework which is a new and unique phenomenon, a qualitative research is conducted. In order to do so, 15 in-depth interviews were held with employees from product teams of 11 organizations, and the interviews were analyzed using thematic analysis. General conditions of teleworking are identified in two categories named as “not working adjacent to coworkers” and “being away from the physical environment of the workplace”. Emergent telework, alongside the general...
An Empirical Study of the Relationship between Emergent States and Behavioral Processes of the Board
, M.Sc. Thesis Sharif University of Technology ; Alavi, Babak (Supervisor)
Abstract
In this research study, the reciprocal relationship between Emergent States and Team Processes has been analyzed in boards of directors, by using case study method with semi-structured interview as the method of data collection and thematic analysis as the method of data analysis. This research was conducted on the companies which are active in Information Technology industries, their size is in the range of SMEs, and have passed the early startup stage and an external investor has joined the board. After thematic analysis, narrating each case’s story, and theoretical analysis on each case, the obtained results are demonstrated with discussion on both cases, introducing a theoretical model,...
Using Probabilistic Models and Data Mining Techniques in Online Computer Games
, M.Sc. Thesis Sharif University of Technology ; Haji, Babak (Supervisor)
Abstract
Computer video games have had a huge growth in recent years, and Dota 2 is one of the most popular video games and e-sports right now. In this research, Dota 2 drafting phase is studied by using stochastic processes and probabilistic models. This phase is modeled as a POMDP (Partially Observable Markov Decision Process) for the first time. Afterwards, the model is solved using data mining methods and machine learning algorithms. A large database of the game's match data is created, and six different machine learning algorithms are used to predict the match outcome based on the drafting stage. The prediction accuracy and power of these algorithms is compared, and finally, a program is...