H. Jarmakani
University of California, San Diego
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Featured researches published by H. Jarmakani.
Presented at: IFSA Conference, Kobe, Japan, Sep 09 - Sep 14, 2007 | 2008
A. Koniges; C S Debonnel; J Andrew; D Eder; D. H. Kalantar; N Masters; A Fisher; R Anderson; B Gunney; B. Brown; K Sain; F Bonneau; J-L Bourgade; J-M. Chevalier; P. Combis; A Geille; J-P Jadaud; Maroni; D Raffestin; J-L Ulmer; J Vierne; A M Tobin; Marc A. Meyers; H. Jarmakani
The debris and shrapnel generated by laser targets are important factors in the operation of a large laser facility such as NIF, LMJ, and Orion. Past experience has shown that it is possible for such target debris to render diagnostics inoperable and also to penetrate or damage optical protection (debris) shields. We are developing the tools to allow evaluation of target configurations in order to better mitigate the generation and impact of debris, including development of dedicated modeling codes. In order to validate these predictive simulations, we briefly describe a series of experiments aimed at determining the amount of debris and/or shrapnel produced in controlled situations. We use glass and aerogel to capture generated debris/shrapnel. The experimental targets include hohlraums (halfraums) and thin foils in a variety of geometries. Post-shot analysis includes scanning electron microscopy and x-ray tomography. We show the results of some of these experiments and discuss modeling efforts.
SHOCK COMPRESSION OF CONDENSED MATTER ‐ 2007: Proceedings of the Conference of the American Physical Society Topical Group on Shock Compression of Condensed Matter | 2008
H. Jarmakani; Yinmin Wang; Eduardo M. Bringa; Marc A. Meyers
A constitutive description of the slip‐to‐twinning transition, based on the critical shear stress, is applied to determine the twinning transition pressures in nanocrystalline nickel and nickel‐tungsten (13 at. %) under shock compression. The model predicts a critical transition pressure of 78 GPa in 30 nm Ni and 16 GPa in 10 nm Ni‐W. These predicted results are in good agreement with laser shock experiments carried out on the same materials.
Bulletin of the American Physical Society | 2005
H. Jarmakani; J. M. McNaney; Mathew Schneider; D. Orlikowski; Jeffrey H. Nguyen; Bimal K. Kad; Marc A. Meyers
A transmission electron microscopy study of quasi‐isentropic high‐pressure loading (peak pressures between 18 GPa and 52 GPa) of polycrystalline and monocrystalline copper was carried out. Deformation mechanisms and defect substructures at different pressures were analyzed. Current evidence suggests a deformation substructure consisting of twinning at the higher pressures and heavily dislocated laths and dislocation cells at the intermediate and lower pressures, respectively. Evidence of stacking faults at the intermediate pressures was also found. Dislocation cell sizes decreased with increasing pressure and increased with distance away from the surface of impact.
Journal De Physique Iv | 2006
Marc A. Meyers; H. Jarmakani; J. M. McNaney; M. S. Schneider; Jeffrey H. Nguyen; Bimal K. Kad
Single crystalline copper was subjected to quasi-isentropic compression via gas-gun and laser loading at pressures between 18GPa and 59GPa. The deformation substructure was analyzed via transmission electron microscopy (TEM). Twins and laths were evident at the highest pressures, and stacking faults and dislocation cells in the intermediate and lowest pressures, respectively. The Preston-Tonks-Wallace (PTW) constitutive description was used to model the slip-twinning process in both cases.
Acta Materialia | 2008
H. Jarmakani; Eduardo M. Bringa; Paul Erhart; B. A. Remington; Yinmin Wang; Nhon Q. Vo; Marc A. Meyers
International Journal of Impact Engineering | 2005
M. S. Schneider; Bimal K. Kad; D. H. Kalantar; B. A. Remington; E.A. Kenik; H. Jarmakani; Marc A. Meyers
Acta Materialia | 2010
H. Jarmakani; Brian Maddox; C.T. Wei; D. H. Kalantar; Marc A. Meyers
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing | 2007
H. Jarmakani; J. M. McNaney; Bimal K. Kad; Daniel Orlikowski; Jeffrey H. Nguyen; Marc A. Meyers
DYMAT 2009 - 9th International Conferences on the Mechanical and Physical Behaviour of Materials under Dynamic Loading | 2009
Marc A. Meyers; H. Jarmakani; B. Cao; C.T. Wei; Bimal K. Kad; B. A. Remington; Eduardo M. Bringa; Brian Maddox; D. H. Kalantar; David C. Eder; A. Koniges
Archive | 2007
Yinmin Wang; Eduardo M. Bringa; Armando Caro; Maria Victoria; J. M. McNaney; James Hawreliak; R. A. Smith; Bruce A. Remington; H. E. Lorenzana; Marc A. Meyers; H. Jarmakani