Mechanical Characterization of Materials for Extreme Environment Applications

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Where is he NOW? - Assistant Professor, Department of Chemical and Materials Engineering, University of Nevada, Reno

"At the Keck Institute in Caltech, my work will focus on the mechanical characterization of materials for extreme environment applications. NASA's future planetary missions to Titan, Europa or Venus—with very low surface temperatures (-180 C) on Titan and very high temperatures (486 C) and high atmospheric pressures (more than 90 times as compared to Earth) on Venus—represent some of the most extreme challenges for mission design and implementation. The primary focus of my work will be to address the long-term lifetime issues of carbon nanotube (CNT)-bundle cathodes, which have been earmarked as efficient high density cold cathodes for such extreme environment electronic applications."(April 2010)

Pathak presentation at the ICB Conference on Insights into Energy Absorption Mechanisms in Hierarchical Carbon Nanotube Forests (.pdf). (February 2012)

Pathak had a winning entry for Artistic Microscopy in the International Metallographic Contest. View his image of Micropillar Fabricated from a Dense Carbon Nanotube Brush. (February 2011)

Pathak contributed to the paper "Size effects in Al nanopillars: Single crystalline vs. bicrystalline" which has been published in Acta Materialia.

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Selected Publications

• Postdoctoral Fellowship Final Report (11.55 MB .pdf)
• S. Pathak, S. Hutchens. Vertically Aligned Carbon Nanotubes, Collective Mechanical Behavior. Encyclopedia of Nanotechnology (Springer). (2016) 2nd edition. pp. 1-20 DOI: 10.1007/978-94-007-6178-0_387-2. ISBN 978-94-007-6178-0 https://doi.org/10.1007/978-94-007-6178-0_387-2.
• S. Pathak, R.D. Doherty, J. Michler, K. Wasmer. Caught in the Act – Grain-Switching and Quadrijunction formation in Annealed Aluminum. Scripta Materialia, 69 (2013) 37–40. https://doi.org/10.1016/j.scriptamat.2013.03.014
• S. Pathak, N Mohan, E Decolvenaere, A Needleman, M Bedewy, AJ Hart, JR. Greer. Local Relative Density Modulates Failure and Strength in Vertically Aligned Carbon Nanotubes. ACS Nano, Vol 7, No 10, pg 8593-8604, 2013. http://dx.doi.org/10.1021/nn402710j
• S. Pathak, J R Raney, C Daraio. Effect of morphology on the strain recovery of vertically aligned carbon nanotube arrays: an in situ study. Carbon. Vol 63, Nov 2013, Pages 303–316. https://doi.org/10.1016/j.carbon.2013.06.083
• S. Pathak, N Mohan, P PSS Abadi, S Graham, B A Cola, JR Greer. Compressive response of vertically aligned carbon nanotube films gleaned from in situ flat-punch indentations. Journal of Materials Research, focus issue DeNovo Carbon Nanomaterials, 28 (7) 201. https://doi.org/10.1557/jmr.2012.366 
• S. Pathak, Ee J. Lim, Parisa P.S.S. Abadi, S Graham, Baratunde A. Cola, Julia R. Greer. Higher Recovery and Better Energy Dissipation at Faster Strain Rates in Carbon Nanotube Bundles: an in-situ Study. ACS Nano, (2012); 6(3): 2189-97. http://pubs.acs.org/doi/abs/10.1021/nn300376j
• S.B. Hutchens, E. Decolvenaere, S. Pathak, J.R. Greer. Nanoshearing. Materials Today, Volume 15, Issue 3, March 2012, Page 127. https://doi.org/10.1016/S1369-7021(12)70048-2
• S. Pathak, S. Hutchens. Vertically Aligned Carbon Nanotubes, Collective Mechanical Behavior. Encyclopedia of Nanotechnology (Springer). (2012) 1st edition, Part 22, 2809-2818, DOI: 10.1007/978-90-481-9751-4_387.
• S. Pathak, J. Michler, K. Wasmer and S.R. Kalidindi. Studying Grain Boundary Regions in Polycrystalline Materials Using Spherical Nano-Indentation and Orientation Imaging Microscopy. J. Materials Science. Volume 47, Issue 2 (2012), Page 815-823. Nominated as finalist for the Journal of Materials Science, Robert W. Cahn Best Paper Prize for 2012 (the “Cahn Prize”). http://dx.doi.org/10.1007/s10853-011-5859-z
• A. Kunz , S. Pathak, J. R. Greer. Size effects in Al nanopillars: single crystalline versus bicrystalline. Acta Materialia (2011) 59(11): p. 4416-4424. https://doi.org/10.1016/j.actamat.2011.03.065
  
  

Selected Book Chapters

• S Pathak. Book chapter titled “Mechanical Behavior of Carbon Nanotubes: from a Single Tube towards Complex Networks”, in "Structure and multiscale mechanics of carbon nanomaterials". 2016. Publisher: International Center for Mechanical Sciences (CISM), Udine, Italy
  
  

Research Fellowships and Awards

• 2012 Director’s Postdoctoral Fellow, Los Alamos National Laboratory, Los Alamos, NM
• 2011 ThinkSwiss Research Scholar – this scholarship provides funding for a research stay in Switzerland (20 scholarships are awarded every year in this nationwide program)
• Work on carbon nanotubes (CNT) selected as the cover image for 2012 for Materials Today through an international level competition.  
• First prize in the NanoArt 2011 International Online Competition http://www.nanotech-now.com/columns/?article=550
• Work featured as a slide show on Discovery Channel news Nov 2011 http://news.discovery.com/tech/scientists-artists-nanoart-exhibition-111109.html
• CNT work featured in Advanced Materials & Processes magazine, Feb 2011
  
  

Invited Presentations

• S. Pathak (presenter), ZG Cambaz, Y Gogotsi, W Mook, J Michler. Viscoelasticity and High Buckling Stress of Dense Carbon Nanotube Brushes. MS&T Annual meeting, Columbus, Ohio, Oct 2011
• S. Pathak (presenter), SR Kalidindi. Studying the Mechanical Response of Regions within Grains and Near Grain Boundaries using Spherical Nanoindentation. TMS Annual meeting, San Diego, Feb-March 2011
  
  

Conference Presentations

• S. Pathak (presenter), Nisha Mohan, Elizabeth Decolvenaere, Alan Needleman, Mostafa Bedewy, Anastasios John Hart,  Julia R. Greer. Effect of density gradients on the deformation of carbon nanotube pillars: an in-situ study. 2012 MRS Fall meeting, Boston, Nov-Dec 2012
• S. Pathak (presenter), N Mohan, Ee J. Lim , PPSS Abadi , S Graham, BA Cola, JR Greer. "Insights into Energy Absorption Mechanisms in Hierarchical Carbon Nanotube Forests."  2012 MRS Spring Meeting, San Francisco, 9-13 April USA.
• S. Pathak (presenter), SR Kalidindi. Studying the Mechanical Response of Regions within Grains and Near Grain Boundaries using Spherical Nanoindentation. ICOTOM annual meeting, IIT Bombay, India, Dec 2011
• S. Pathak (presenter), ZG Cambaz, Y Gogotsi, W Mook, J Michler. Viscoelasticity and High Buckling Stress of Dense Carbon Nanotube Brushes. TMS Annual meeting, San Diego, Feb-March 2011
• S. Pathak (presenter), SR Kalidindi, R Raghavan, J Michler. Stress-strain response from spherical nano-indentation and micro-pillar compression experiments: A comparative study. TMS Annual meeting, San Diego, Feb-March 2011
• S. Pathak (presenter), JL Riesterer, SJ Vachhani, K Wasmer, J Michler, SR Kalidindi. “On the Sequence of Events during Pop-ins in Spherical Nanoindentation”; MRS Fall meeting, Boston, Nov-Dec 2010
  
  

Poster Presentations

• S. Pathak, N Mohan, Ee J. Lim , PPSS Abadi , S Graham, BA Cola, JR Greer. "Insights into Energy Absorption Mechanisms in Hierarchical Carbon Nanotube Forests."  2012 ICB Army-Industry Collaboration Conference and Comprehensive Review, Santa Barbara, CA, USA
• S. Pathak, W Mook, ZG Cambaz, Y Gogotsi, J Michler. “In-situ SEM Micro-compression of Dense Carbon Nanotube Brushes”; MRS Fall Meeting, Boston, 2010
  
  

Science Saturdays – Caltech Public Science lecture series

• "Hyperspeed" – Discussion leader for Caltech outreach program (audience of 500), Feb 12, 2011