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Mixed pressure and AC electroosmotically driven flow with asymmetric wall zeta potential and hydrophobic surfaces
, Article ASME 2013 Heat Transfer Summer Conf. Collocated with the ASME 2013 7th Int. Conf. on Energy Sustainability and the ASME 2013 11th Int. Conf. on Fuel Cell Science, Engineering and Technology, HT 2013 ; Volume 1 , 2013 ; 9780791855478 (ISBN) ; Sharif University of Technology
2013
Abstract
The present study examines Alternating Current (AC) electroosmotic flows in a parallel plate microchannel subject to constant wall temperature. Numerical method consists of a central finite difference scheme for spatial terms and a forward difference scheme for the temporal term. Asymmetric boundary conditions are assumed for Poison-Boltzmann equation for determining the electric double layer (EDL) potential distribution. The potential distribution is then used to evaluate the velocity distribution. The velocity distribution is obtained by applying slip boundary conditions on the walls which accounts for probable hydrophobicity of surfaces. After determining the velocity distribution...
Evaluation of 1991 NIOSH Lifting Equation in Controlling the Biomechanical Loads of the Human Spine
, M.Sc. Thesis Sharif University of Technology ; Arjmand, Navid (Supervisor)
Abstract
The 1991 NIOSH Lifting Equation (NLE) is widely used to assess risk of injury to the spine by providing estimates of the recommended weight limit (RWL) in hands. The present study uses two biomechanical models of the spine to verify whether the RWL generates L5-S1 loads within the limits (e.g., 3400 N for compression recommended by NIOSH and 1000 N for shear recommended in some studies).Severallifting activities are simulated here to evaluate the RWL by the NLE and the L5-S1 loads by the models. In lifting activities involving moderate to large forward trunk flexion, the estimated RWL generates L5-S1 spine loads exceeding the recommended limits. The NIOSH vertical multiplier is the likely...
Applying and inferring fuzzy trust in Semantic Web social networks
, Article 1st Canadian Semantic Web Working Symposium, CSWWS 2006, Quebec City, QC, 6 June 2006 through 6 June 2006 ; 2006 , Pages 23-43 ; 9780387298153 (ISBN) ; Bagheri, S ; Sharif University of Technology
Kluwer Academic Publishers
2006
Abstract
Social networks let the people find and know other people and benefit form their information. Semantic Web standard ontologies support social network sites for making use of other social networks information and hence help their expansion and unification, making them a huge social network. As social networks are public virtual social places much information may exist in them that may not be trustworthy to all. A mechanism in needed to rate coming news, reviews and opinions about a definite subject from users, according to each user preference. There should be a feature for users to specify how much they trust a friend and a mechanism to infer the trust from one user to another that is not...
Fuzzy trust inference in trust graphs and its application in semantic web social networks
, Article 2006 World Automation Congress, WAC'06, Budapest, 24 June 2006 through 26 June 2006 ; 2006 ; 1889335339 (ISBN); 9781889335339 (ISBN) ; Bagheri, S ; Sharif University of Technology
IEEE Computer Society
2006
Abstract
People generate information or get it from the others. When one gets information from the others it is important to get it from trusted ones. Each individual in a society can get the information he needs form his trusted friends but there are also many other people in the society that he or she indirectly trusts and can benefit from their information. The idea of benefiting from the indirectly trusted people can well be employed in social networks where finding trusted people can be automated. There should be a feature for users to specify how much they trust a friend and a mechanism to infer the trust in the society trust graph from one user to another that is not directly a friend of the...
Electroosmotic Flow in Microchannels
, M.Sc. Thesis Sharif University of Technology ; Saeedi, Mohammad Saeed (Supervisor)
Abstract
The present study examines both Direct Current (DC) and Alternating Current (AC) electroosmotic flows in a parallel plate microchannel. The method consists of a central finite difference scheme for spatial terms and a forward difference scheme for the temporal term. Asymmetric boundary conditions are assumed for Poison-Boltzmann equation used to determine the electric double layer (EDL) potential distribution. The potential distribution is then used to evaluate the velocity distribution for both DC and AC electroosmotic flows. The velocity distributions are obtained by applying slip boundary conditions on the walls to account for probable hydrophobicity of the surfaces. After determining the...
Seismic Risk and Resilience of a System of Systems: Analysis of a Virtual City
,
M.Sc. Thesis
Sharif University of Technology
;
Mahsoli, Mojtaba
(Supervisor)
Abstract
The fundamental objective of this study is to present seismic hazard, risk and resilience assessment of a virtual city using sampling and agent-based simulation in two levels of refinement. In this context, hazard is the exceedance probability of ground shaking intensity, risk is exceedance probability of measures such as loss, and resilience is the ability to quickly recover after a hazard event. This study utilizes the Rtx risk and resilience assessment framework established at the Center for Infrastructure Sustainability and Resilience Research (INSURER) at Sharif University of Technology. This framework employs multiple interacting probabilistic models to quantify the risk and...
Design, analysis, and implementation of extra low air-gap single-phase axial-flux induction motors for low-cost applications
, Article International Transactions on Electrical Energy Systems ; Volume 26, Issue 12 , 2016 , Pages 2516-2531 ; 20507038 (ISSN) ; Nasiri Gheidari, Z ; Lesani, H ; Sharif University of Technology
John Wiley and Sons Ltd
2016
Abstract
In this paper, design and prototyping of two-speed capacitor-run single-phase axial-flux induction motor (AFIM) for direct-drive applications is presented. The proposed structure has single stator-single rotor configuration with high magnetic pull between the stator and rotor, which may compel rotor to lock. Although the most efficient method to overcome this problem is using a second rotor or stator in the mirror with the first one, it is not applicable in low-cost applications. So, in this paper, two new and fast construction techniques are proposed to fabricate an AFIM with extra low air-gap length and minimum cost. Beside design and optimization process, a thermal equivalent circuit...
Polynomial-time fence insertion for structured programs
, Article 33rd International Symposium on Distributed Computing, DISC 2019, 14 October 2019 through 18 October 2019 ; Volume 146 , 2019 ; 18688969 (ISSN); 9783959771269 (ISBN) ; Pourdamghani, A ; Lesani, M ; Suomela J ; Sharif University of Technology
Schloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing
2019
Abstract
To enhance performance, common processors feature relaxed memory models that reorder instructions. However, the correctness of concurrent programs is often dependent on the preservation of the program order of certain instructions. Thus, the instruction set architectures offer memory fences. Using fences is a subtle task with performance and correctness implications: using too few can compromise correctness and using too many can hinder performance. Thus, fence insertion algorithms that given the required program orders can automatically find the optimum fencing can enhance the ease of programming, reliability, and performance of concurrent programs. In this paper, we consider the class of...
Free Vibration Analysis of Composite Sandwich Cylindrical Shells with Magneto-Rheological Fluid Core
, M.Sc. Thesis Sharif University of Technology ; Koochakzadeh, Mohammad Ali (Supervisor)
Abstract
Free vibration characteristics analysis of circular sandwich cylindrical shells will be investigated in this research. Sanders thin shell theory will be used for modeling base and constraint layers. Hamilton Principals will be applied to obtain governing equation of motion for the problem. Galerkin-Fourier procedure will be used to solve obtained partial differential equation of the sandwich cylindrical shell. Effects of magnetic field intensity, MR layer, base layer and constraint layer thicknesses, and boundary conditions will be investigated on vibration frequency and modal loss factor of the cylindrical shell. Finally, we will compare the performance of using a viscoelastic and an...
Hour-ahead demand forecasting in smart grid using support vector regression (SVR)
, Article International Transactions on Electrical Energy Systems ; Vol. 24, issue. 12 , 2014 , p. 1650-1663 ; Fereidunian A ; Gholami-Dehkordi H ; Lesani H ; Sharif University of Technology
2014
Abstract
Demand forecasting plays an important role as a decision support tool in power system management, especially in smart grid and liberalized power market. In this paper, a demand forecasting method is presented by using support vector regression (SVR). The proposed method is applied to practical hourly data of the Greater Tehran Electricity Distribution Company. The SVR parameters are selected by using a grid optimization process and an investigation on different kernel functions. Moreover, correlation analysis is used to find exogenous variables. Acceptable accuracy of load prediction is shown by comparing the result of SVR model to that of the artificial neural networks and the actual data,...
Identification of external power system linear dynamic equivalents as MIMO feedback blocks for the study system
, Article International Journal of Emerging Electric Power Systems ; Volume 8, Issue 5 , 21 Nov. 2007 , 2007 ; 1553779X (ISSN) ; Ranjbar, A. M ; Lesani, H ; Radmanesh, H ; Sharif University of Technology
2007
Abstract
The necessity of dynamic equivalents for power system analysis has been well known since the expansion of large interconnected power networks, and has been discussed during the last decades. The present paper proposes a new method for constructing dynamic equivalents of power systems. In this method, at the first step the "study system" is modeled completely via a single machineinfinite bus modeling procedure. Then the "external system" is identified as a MIMO feedback block of this model in such a manner that can include dynamic effects of the latter on the behavior of the former. The method is successfully experimented on a part of the Iranian southern network. Copyright © 2007 The...
Communication protocol evolution by natural selection
, Article CIMCA 2006: International Conference on Computational Intelligence for Modelling, Control and Automation, Jointly with IAWTIC 2006: International Conference on Intelligent Agents Web Technologies and International Commerce, Sydney, NSW, 28 November 2006 through 1 December 2006 ; 2006 ; 0769527310 (ISBN); 9780769527314 (ISBN) ; Shouraki, S. B ; Halavati, R ; Lesani, M ; Sharif University of Technology
IEEE Computer Society
2006
Abstract
One of the most important issues discussed in multi-agent systems, is communication between agents. Usually, a predefined communication protocol is used, but predefining a protocol between agents causes some problems; for example it is possible that agents recognize a subject that is not defined in their protocol so they can't express anything about it. In this paper we propose a new method for evolution of a communication protocol between intelligent agents by using natural selection mechanism. Experimental results will be discussed in detail. © 2006 IEEE
Study, Analysis & Optimizing The Process Of Approval, Design & Implementation Of Projects In The Iranian Oil Terminal Company(IOTC)
, M.Sc. Thesis Sharif University of Technology ; Mostafavi, Mostafa (Supervisor)
Abstract
Since the Iranian oil terminals company(I.O.T.C.) has been the main and strategic gateway of exporting petroleum in the country and plays an important role in the optimum continuity of national, regional and international energy supply chain and also conducting the needed projects whit a desirable quality and minimum time and cost has a prominent influence on steady continuity of manufacturing, importing and exporting of petroleum and gas production. The main purpose of doing this thesis is diagnosing the process of approval, design and implementation of projects in the I.O.T.C., Thus, whit regarding to the modern needs of implementing projects and the necessity of reviewing the structure...
Study & Analysis of Delays Causes of Gas Projects in Tehran Gas Company & presenting Optimized Solutions by Applying Project Management Principles
, M.Sc. Thesis Sharif University of Technology ; Mostafavi, Mostafa (Supervisor)
Abstract
To deliver gas in time to different consumers like as industrial, commercial and domestic users is one of the most important parts in gas industry. So it is very important to utilize these projects in the specified time. There are huge harms for client, contractors and consumers when there is a delay in project utilization. To identify effective parameters on delays to remove them in future is an essential factor. In this research, all delay causes for TPGC (Tehran Province Gas Company) projects are analyzed and some solutions to remove these delays are presented. 10 hypotheses in relation of gas delivery have been assumed as delay causes. Then some questions have been discussed in relation...
Service Level Agreement Templates and Guides for Implementing, using eTOM
, M.Sc. Thesis Sharif University of Technology ; Mostafavi, Mostafa (Supervisor)
Abstract
Nowadays, in communication industry, specially data network, in which service quality is a serious parameter, request for making connection with appropriate quality (Proportionate to demands) and necessity of clarification of obligations of service providers and customers, as well as customer awareness of submitted materials and offering various services with different qualities & costs, led service providers, specially IP based networks, to make agreements with their customers, entitled service Level Agreement (SLA). The SLA specifies the service type, mutual obligations, related parameters, measuring methods, violation threshold, penalties and loss compensation. Whereas, applying...
Condition Monitoring of Water Pipelines by Using Acoustic Method a Study of Leak Detection in ABFA
, M.Sc. Thesis Sharif University of Technology ; Mostafavi, Mostafa (Supervisor)
Abstract
Water is crucial to human being. We use water for a wide variety of uses daily. However, leakage has caused substantial water loss to our precious processed water. The major contributor to non-revenue water in Iran is pipeline leakages. The water industry in the nation has invested in equipment to detect and localize leaks in water distribution systems. One of the equipment mentioned is acoustic-based. The principle of acoustic is that whenever a leak is present in a pipeline, noise is generated and will travel along the pipeline. The acoustic leak detection method is then derived by calculating the distance traveled by this noise generated by the leak. Different equipment based on acoustic...
Assessment and Performance Improvement of Hierarchical Voltage Control System
, M.Sc. Thesis Sharif University of Technology ; Parniani, Mostafa (Supervisor)
Abstract
Hierarchical voltage control is one of the conventional kinds of coordinated voltage control schemes which has been studied in some countries in the last decades. In this method network is divided into several voltage control regions and in each region voltage profile is controlled near optimal level, satisfying the economic and secure goals of the network performance. In this thesis, after the explanation of the main concepts of this scheme, its effects on the network voltage control is assessed and its performance is improved. First the primary concepts of hierarchical voltage control are explained. Then, the methods of the control regions determination and pilot nodes selection are...
Analyzing the Healthcare Wastes and Feasibility Study of Related Items (Plastics)
, M.Sc. Thesis Sharif University of Technology ; Mostafavi, Mostafa (Supervisor)
Abstract
Increasing population and competition for producing various productions and also more consumption in recent decades, result in producing more wastes. Therefore effective and continuous waste management is essential for monitoring the process (from the wastes generation source to the waste disposal) and establishing the efficient strategies to reduce wastes. One of the major sources of waste generation is hospitals that cause lots of environmental problem unless they are managed properly.Recycling is an important element of waste management that can reduce costs by innovative and proper management. The purpose of this research is identification of recyclable plastic items and estimates the...
The Analysis of Total Productive Maintenance Based on Computerized Maintenance Management System
, M.Sc. Thesis Sharif University of Technology ; mostafavi, mostafa (Supervisor)
Abstract
The main purpose of this thesis is to analyze the total productive maintenance based on computerized maintenance management system. At first, a detailed study on total productive maintenance is performed and then the requirements of this maintenance strategy are specified. Also, a computerized maintenance management system is defined which can help total productive maintenance to reach to its requirements. Finally, a conceptual model and entity-relationship model for computerized maintenance management system data base has been created
Study of HVDC Transmission for Offshore Wind Farms Based on Voltage Source Converters
, M.Sc. Thesis Sharif University of Technology ; Parniani, Mostafa (Supervisor)
Abstract
In this thesis, DC transmission of offshore wind farms is studied thoroughly. Various system configurations that are introduced in the literatures are discussed and their control scheme for normal conditions and grid faults are studied. Then, the HVDC transmission based on voltage source converter, located between a local offshore ac grid and the onshore ac system is investigated as the most practical choice. The HVDC linke circuit elements are calculated and the control strategies of the offshore and onshore converters are introduced. DFIGs are considered to be the best choice for the offshore wind turbine generators. Then, the system is simulated and the frequency of the offshore grid is...