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Total 25 records
On the solution treatment of severely deformed AA2024-O and subsequent natural aging
, Article Journal of Materials Research and Technology ; Volume 20 , 2022 , Pages 1558-1569 ; 22387854 (ISSN) ; Kazeminezhad, M ; Sharif University of Technology
Elsevier Editora Ltda
2022
Abstract
In this research, the effect of applying severe strain before solid solution treatment (SST) for AA2024-O was studied. Providing concurrent insights into solutionizing behavior and microstructural evolution corresponding to hardness is important. Multi-directional forging (MDF) was used as a severe plastic deformation (SPD) method. After applying SST on MDFed (4 passes) and as-annealed samples, natural aging (NA) was used as the following treatment to examine the role of severe strain on the solutionizing behavior. In most previous attempts, SPD has been used after SST, but one of the innovations of the present work is the study of SPD before SST. Experimental results show that adding a...
Electron trajectory evaluation in laser-plasma interaction for effective output beam
, Article Chinese Physics B ; Volume 19, Issue 6 , 2010 ; 16741056 (ISSN) ; Sadighi Bonabi, R ; Afarideh, H ; Sharif University of Technology
2010
Abstract
Using the ellipsoidal cavity model, the quasi-monoenergetic electron output beam in laser-plasma interaction is described. By the cavity regime the quality of electron beam is improved in comparison with those generated from other methods such as periodic plasma wave field, spheroidal cavity regime and plasma channel guided acceleration. Trajectory of electron motion is described as hyperbolic, parabolic or elliptic paths. We find that the self-generated electron bunch has a smaller energy width and more effective gain in energy spectrum. Initial condition for the ellipsoidal cavity is determined by laser-plasma parameters. The electron trajectory is influenced by its position, energy and...
Flow field analysis around the ship fin stabilizer including free surface
, Article Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, 31 May 2009 through 5 June 2009, Honolulu, HI ; Volume 4, Issue PART A , 2009 , Pages 603-608 ; 9780791843444 (ISBN) ; Ghassemi, H ; Ghadimi, P ; Ommani, B ; Sharif University of Technology
Abstract
Fin stabilizers are very important device for controlling the ship roll motion against the external moments due to wave. This paper presents numerical results for flow field simulation and the hydrodynamic performance of fin stabilizer attached to a ship hull with free surface effects. Combination of CFD and RANS method has been used for this study. The fin is nonrectangular NACA0015 profile section with a finite aspect ratio. The numerical results include pressure distributions and flow field around the fin which are used to calculate lift coefficients and free surface elevation as the main interest. Some results are compared with available experimental and numerical data in literature and...
Pseudo DVL reconstruction by an evolutionary TS-fuzzy algorithm for ocean vehicles
, Article Measurement: Journal of the International Measurement Confederation ; Volume 147 , 2019 ; 02632241 (ISSN) ; Hashemi, M ; Salarieh, H ; Sharif University of Technology
Elsevier B.V
2019
Abstract
By development of ocean exploration, autonomous vehicles are employed to perform on-water and underwater tasks. Using an extended Kalman filter, Inertial Navigation System/Doppler Velocity Log (INS/DVL) integrated systems are trying to navigate in oceans and underwater environments when Global Positioning System (GPS) signals are not accessible. The dependency of DVL signals on acoustic environments may cause any DVL malfunction due to sea creatures or strong wave-absorbing material. In this paper, an improved version of evolutionary TS-fuzzy (eTS) is proposed in order to predict DVL sensor outputs at DVL malfunction moment, by utilizing an artificial intelligent (AI) aided integrated...
Iran atlas of offshore renewable energies
, Article Renewable Energy ; Volume 36, Issue 1 , January , 2011 , Pages 388-398 ; 09601481 (ISSN) ; Rahimi, R ; Sharif University of Technology
2011
Abstract
The aim of the present study is to provide an Atlas of IRAN Offshore Renewable Energy Resources (hereafter called 'the Atlas') to map out wave and tidal resources at a national scale, extending over the area of the Persian Gulf and Sea of Oman. Such an Atlas can provide necessary tools to identify the areas with greatest resource potential and within reach of present technology development. To estimate available tidal energy resources at the site, a two-dimensional tidally driven hydrodynamic numerical model of Persian Gulf was developed using the hydrodynamic model in the MIKE 21 Flow Model (MIKE 21HD), with validation using tidal elevation measurements and tidal stream diamonds from...