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Hybrid Switching of Harvesting Energy Systems Based on Peizoelectric Material
, M.Sc. Thesis Sharif University of Technology ; Alasty, Aria (Supervisor) ; Salarieh, Hasan (Supervisor)
Abstract
For many low-powered portable and wireless electronic applications the finite energy density of chemical batteries places limits on their functional lifetime. Through the use of energy harvesting techniques, ambient vibration energy can be captured and converted into usable electricity in order to create self-powering systems which are not limited by finite battery energy. Typical energy harvesting systems are composed of two components, a transducer that converts the mechanical vibrations into electrical energy and a power converter that efficiently delivers the harvested energy to the electronic load. The practical design of energy harvesting systems must include both components and...
Planning of multi-hub energy system by considering competition issue
, Article International Journal of Sustainable Energy Planning and Management ; Volume 30 , 2021 , Pages 5-20 ; 22462929 (ISSN) ; Rajabi Ghahnavieh, A ; Haghi, E ; Sharif University of Technology
Aalborg University press
2021
Abstract
Energy hub concept has been emerged as a suitable tool to analyze multi-carrier energy systems. Deregulation and increasing competition in the energy industry have provided a suitable platform for developing the multi-agent energy systems. Planning of energy hubs considering the competition between the hubs has not been sufficiently addressed, yet. A model has been proposed in this study for planning of a multi-hub energy system considering the competition between the hubs. The hubs are interconnected via an electric transmission system. A linear model has been developed to determine the optimal planning/operation strategy for energy hubs in a multi-period planning horizon to meet the heat...
Design and lmplementation of Wireless Electric Vehicle Charger using Multilevel Converters with Misalignment Compensation
, M.Sc. Thesis Sharif University of Technology ; Tahami, Farzad (Supervisor)
Abstract
Wireless power transfer has been found to be a practical replacement for cable power transfer in a wide range of applications. For instance, this technology offers significant solutions for medical and industrial applications as well as electrical home appliances and electric vehicle chargers. All over the world, researchers are investigating and implementing experimental prototypes to simplify power transfer in applications in which the use of cables is impossible, troublesome, or hazardous. There are different issues in each of the mentioned applications which should be solved in order to use wireless power transfer systems more beneficially. These issues include power transfer efficiency,...
A tunable vibration absorber design to suppress chatter in boring manufacturing process
, Article ASME International Mechanical Engineering Congress and Exposition, IMECE 2007, Seattle, WA, 11 November 2007 through 15 November 2007 ; Volume 9 PART C , 2008 , Pages 1943-1950 ; 0791843033 (ISBN); 9780791843031 (ISBN) ; Bakhtiari Nejad, F ; Movahhedi, M. R ; Sharif University of Technology
2008
Abstract
Dynamic vibration absorbers are used to reduce the undesirable vibrations in many applications such as electrical transmission lines, helicopters, gas turbines, engines, bridges and etc. One type of these absorbers is tunable vibration absorber (TVA) which can act as a semi-active controller. In this paper, by applying a (TVA), chatter vibration is suppressed during boring process in which boring bar is modeled as a cantilever Euler-Bernoulli beam. The optimum specifications of absorber such as spring stiffness, absorber mass and its position can be determined by developing an algorithm based upon mode summation method. Finally, using the SIMULINK Toolbox of MATLAB, the analog simulated...
A comprehensive framework for optimal planning of competing energy hubs based on the game theory
, Article Sustainable Energy, Grids and Networks ; Volume 27 , 2021 ; 23524677 (ISSN) ; Rajabi Ghahnavieh, A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
The concept of energy hub has been used recently to study multi-carrier energy systems. A model has been proposed in this paper for planning multi-hub energy system considering the competition between the hubs. The energy hubs are interconnected by a power grid. Hubs supply the demands for heat and electricity using various technologies and access to several energy carriers. To this aim, load zones were used to incorporate demand profiles for both heat and electricity in the different seasons of the year. Supplying the demand most cost-effectively is the objective function of each hub. These hubs select the optimum strategy separately in a competitive space. The power grid is owned by...
Using a vibration absorber to suppress chatter vibration in turning process with a worn tool
, Article Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference 2009, DETC2009, 30 August 2009 through 2 September 2009 ; Volume 1, Issue PART B , August-September , 2010 , Pages 1335-1341 ; 9780791848982 (ISBN) ; Bakhtiari Nejad, F ; Movahhedi, M. R ; Sharif University of Technology
2010
Abstract
Dynamic vibration absorbers are used as semi-active controllers to reduce the undesirable vibrations in many applications such as electrical transmission lines, helicopters, gas turbines, engines, bridges and etc. One type of these absorbers is tunable vibration absorber (TVA). In this paper, regenerative chatter in an orthogonal turning process is suppressed using a (TVA). It is shown that TVA can modify the frequency response function of the cutting tool so as to improve cutting stability in turning process. In addition, tool wear is an important factor which works as a positive damping and helps the chatter suppression beside exertion of the TVA. Finally, using the SIMULINK Toolbox of...
Using a vibration absorber to suppress chatter vibration in turning process with a worn tool
, Article Proceedings of the ASME Design Engineering Technical Conference, 30 August 2009 through 2 September 2009, San Diego, CA ; Volume 1, Issue PARTS A AND B , 2009 , Pages 1335-1341 ; 9780791848982 (ISBN) ; Bakhtiari Nejad, F ; Movahhedi, M. R ; Sharif University of Technology
Abstract
Dynamic vibration absorbers are used as semi-active controllers to reduce the undesirable vibrations in many applications such as electrical transmission lines, helicopters, gas turbines, engines, bridges and etc. One type of these absorbers is tunable vibration absorber (TVA). In this paper, regenerative chatter in an orthogonal turning process is suppressed using a (TVA). It is shown that TVA can modify the frequency response function of the cutting tool so as to improve cutting stability in turning process. In addition, tool wear is an important factor which works as a positive damping and helps the chatter suppression beside exertion of the TVA. Finally, using the SIMULINK Toolbox of...
Tuneable vibration absorber design to suppress vibrations: An application in boring manufacturing process
, Article Journal of Sound and Vibration ; Volume 318, Issue 1-2 , 2008 , Pages 93-108 ; 0022460X (ISSN) ; Bakhtiari Nejad, F ; Movahhedy, M. R ; Sharif University of Technology
2008
Abstract
Dynamic vibration absorbers are used to reduce the undesirable vibrations in many applications such as electrical transmission lines, helicopters, gas turbines, engines, bridges, etc. Tuneable vibration absorbers (TVA) are also used as semi-active controllers. In this paper, the application of a TVA for suppression of chatter vibrations in the boring manufacturing process is presented. The boring bar is modeled as a cantilever Euler-Bernoulli beam and the TVA is composed of mass, spring and dashpot elements. In addition, the effect of spring mass is considered in this analysis. After formulation of the problem, the optimum specifications of the absorber such as spring stiffness, absorber...
Well-designed Ag/ZnO/3D graphene structure for dye removal: Adsorption, photocatalysis and physical separation capabilities
, Article Journal of Colloid and Interface Science ; Volume 537 , 2019 , Pages 66-78 ; 00219797 (ISSN) ; Samadi, M ; Asadian, E ; Zhou, Y ; Dong, C ; Zhang, J ; Moshfegh Zaker, A. R ; Sharif University of Technology
Academic Press Inc
2019
Abstract
In this research, adsorption and photocatalytic degradation process were utilized to remove organic dye from wastewater. To accomplish that, a newly-designed ternary nanostructure based on Ag nanoparticles/ZnO nanorods/three-dimensional graphene network (Ag NPs/ZnO NRs/3DG) was prepared using a combined hydrothermal-photodeposition method. The three-dimensional structure of graphene hydrogel as a support for growth of ZnO nanorods was characterized using field emission scanning electron microscopy (FESEM). In addition, diameter of silver nanoparticles grown on the ZnO nanorods with the average aspect ratio of 5 was determined in the range of 30–80 nm by using transmission electron microscopy...
Biomimetic proteoglycan nanoparticles for growth factor immobilization and delivery
, Article Biomaterials Science ; Volume 8, Issue 4 , 2020 , Pages 1127-1136 ; Mostafavi, E ; Shokrgozar, M. A ; Tamjid, E ; Webster, T. J ; Annabi, N ; Simchi, A ; Sharif University of Technology
Royal Society of Chemistry
2020
Abstract
The delivery of growth factors is often challenging due to their short half-life, low stability, and rapid deactivation. In native tissues, the sulfated residual of glycosaminoglycan (GAG) polymer chains of proteoglycans immobilizes growth factors through the proteoglycans'/proteins' complexation with nanoscale organization. These biological assemblies can influence growth factor-cell surface receptor interactions, cell differentiation, cell-cell signaling, and mechanical properties of the tissues. Here, we introduce a facile procedure to prepare novel biomimetic proteoglycan nanocarriers, based on naturally derived polymers, for the immobilization and controlled release of growth factors....