Documents disponibles écrits par cet auteur

Development of novel grain morphology during hot extrusion of magnesium AZ21 alloy / M. A. Azeem in Acta materialia, Vol. 58 N° 5 (Mars 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 5 (Mars 2010) . - pp. 1495–1502 Titre : Development of novel grain morphology during hot extrusion of magnesium AZ21 alloy Type de document : texte imprimé Auteurs : M. A. Azeem, Auteur ; A. Tewari, Auteur ; S. Mishra, Auteur Année de publication : 2011 Article en page(s) : pp. 1495–1502 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Magnesium  alloy  Extrusion  Dynamic  recrystallization  Annealing  Electron  backscattering  diffraction  (EBSD) Résumé : Microstructure and microtexture evolution during static annealing of a hot-extruded AZ21 magnesium alloy was studied. Apart from fine recrystallized equiaxed grains and large elongated deformed grains, a new third kind of abnormal grains that are stacked one after the other in a row parallel to the extrusion direction were observed. The crystallographic misorientation inside these grains was similar to that of the fine recrystallized grains. The large elongated grains exhibited significant in-grain misorientation. A self-consistent mechanistic model was developed to describe the formation of these grain morphologies during dynamic recrystallization (DRX). The texture of pre-extruded material, although lost in DRX, leaves a unique signature which manifests itself in the form of these grain morphologies. The origin of abnormal stacked grains was associated with slow nucleation in pre-extruded grains of a certain orientation. Further annealing resulted in large secondary recrystallized grains with occasional extension twins. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409007599 [article] Development of novel grain morphology during hot extrusion of magnesium AZ21 alloy [texte imprimé] / M. A. Azeem, Auteur ; A. Tewari, Auteur ; S. Mishra, Auteur . - 2011 . - pp. 1495–1502. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 5 (Mars 2010) . - pp. 1495–1502 Mots-clés : Magnesium  alloy  Extrusion  Dynamic  recrystallization  Annealing  Electron  backscattering  diffraction  (EBSD) Résumé : Microstructure and microtexture evolution during static annealing of a hot-extruded AZ21 magnesium alloy was studied. Apart from fine recrystallized equiaxed grains and large elongated deformed grains, a new third kind of abnormal grains that are stacked one after the other in a row parallel to the extrusion direction were observed. The crystallographic misorientation inside these grains was similar to that of the fine recrystallized grains. The large elongated grains exhibited significant in-grain misorientation. A self-consistent mechanistic model was developed to describe the formation of these grain morphologies during dynamic recrystallization (DRX). The texture of pre-extruded material, although lost in DRX, leaves a unique signature which manifests itself in the form of these grain morphologies. The origin of abnormal stacked grains was associated with slow nucleation in pre-extruded grains of a certain orientation. Further annealing resulted in large secondary recrystallized grains with occasional extension twins. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409007599

Improving stability of a DFIG-based wind power system with tuned damping controller / Mishra Y in IEEE transactions on energy conversion, Vol. 24 N° 3 (Septembre 2009) 

Public ISBD [article]  in IEEE transactions on energy conversion > Vol. 24 N° 3 (Septembre 2009) . - pp. 650 - 660 Titre : Improving stability of a DFIG-based wind power system with tuned damping controller Type de document : texte imprimé Auteurs : Mishra Y, Auteur ; S. Mishra, Auteur ; Tripathy M, Auteur Année de publication : 2010 Article en page(s) : pp. 650 - 660 Note générale : Energy Conversion Langues : Anglais (eng) Mots-clés : Asynchronous  generators--Damping--Time-domain  analysis--Wind  power  plants Résumé : This paper focuses on the implementation of a damping controller for the doubly fed induction generator (DFIG) system. Coordinated tuning of the damping controller to enhance the damping of the oscillatory modes is presented using bacterial foraging technique. The effect of the tuned damping controller on converter ratings of the DFIG system is also investigated. The results of both eigenvalue analysis and the time-domain simulation studies are presented to elucidate the effectiveness of the tuned damping controller in the DFIG system. The improvement of the fault ride-through capability of the system is also demonstrated. Note de contenu : Bibiogr. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5075556&sortType%3Das [...] [article] Improving stability of a DFIG-based wind power system with tuned damping controller [texte imprimé] / Mishra Y, Auteur ; S. Mishra, Auteur ; Tripathy M, Auteur . - 2010 . - pp. 650 - 660. Energy Conversion Langues : Anglais (eng) in IEEE transactions on energy conversion > Vol. 24 N° 3 (Septembre 2009) . - pp. 650 - 660 Mots-clés : Asynchronous  generators--Damping--Time-domain  analysis--Wind  power  plants Résumé : This paper focuses on the implementation of a damping controller for the doubly fed induction generator (DFIG) system. Coordinated tuning of the damping controller to enhance the damping of the oscillatory modes is presented using bacterial foraging technique. The effect of the tuned damping controller on converter ratings of the DFIG system is also investigated. The results of both eigenvalue analysis and the time-domain simulation studies are presented to elucidate the effectiveness of the tuned damping controller in the DFIG system. The improvement of the fault ride-through capability of the system is also demonstrated. Note de contenu : Bibiogr. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5075556&sortType%3Das [...]

Small-signal stability analysis of a DFIG-based wind power system under different modes of operation / Mishra, Yateendra in IEEE transactions on energy conversion, Vol. 24 N° 4 (Décembre 2009) 

Public ISBD [article]  in IEEE transactions on energy conversion > Vol. 24 N° 4 (Décembre 2009) . - pp. 972 - 982 Titre : Small-signal stability analysis of a DFIG-based wind power system under different modes of operation Type de document : texte imprimé Auteurs : Mishra, Yateendra, Auteur ; S. Mishra, Auteur ; Fangxing, Li, Auteur Année de publication : 2010 Article en page(s) : pp. 972 - 982 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : Asynchronous  generators;  damping;  robust  control;  wind  power Résumé : This paper focuses on the super/subsynchronous operation of the doubly fed induction generator (DFIG) system. The impact of a damping controller on the different modes of operation for the DFIG-based wind generation system is investigated. The coordinated tuning of the damping controller to enhance the damping of the oscillatory modes using bacteria foraging technique is presented. The results from eigenvalue analysis are presented to elucidate the effectiveness of the tuned damping controller in the DFIG system. The robustness issue of the damping controller is also investigated. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5308249&sortType%3Das [...] [article] Small-signal stability analysis of a DFIG-based wind power system under different modes of operation [texte imprimé] / Mishra, Yateendra, Auteur ; S. Mishra, Auteur ; Fangxing, Li, Auteur . - 2010 . - pp. 972 - 982. energy conversion Langues : Anglais (eng) in IEEE transactions on energy conversion > Vol. 24 N° 4 (Décembre 2009) . - pp. 972 - 982 Mots-clés : Asynchronous  generators;  damping;  robust  control;  wind  power Résumé : This paper focuses on the super/subsynchronous operation of the doubly fed induction generator (DFIG) system. The impact of a damping controller on the different modes of operation for the DFIG-based wind generation system is investigated. The coordinated tuning of the damping controller to enhance the damping of the oscillatory modes using bacteria foraging technique is presented. The results from eigenvalue analysis are presented to elucidate the effectiveness of the tuned damping controller in the DFIG system. The robustness issue of the damping controller is also investigated. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5308249&sortType%3Das [...]