This letter from Professor Anthony D. Rollett provides a strong recommendation for Suraj Rao. It details Suraj's work as a master's student in Professor Rollett's research group on 3D printing of aluminum powders for Carnegie Mellon University and Alcoa. Suraj quickly learned various characterization techniques and applied them to analyze powder samples. He helped resolve a data discrepancy and took charge of analyzing large 3D reconstructed images from synchrotron testing to reveal porosity variations from processing conditions. Professor Rollett expects Suraj's paper on this work will attract attention in the additive manufacturing community. He states Suraj performed well above expectations and was a key member of the project team.

1. Carnegie Mellon Department of Materials Science
and Engineering
Carnegie Mellon University
4315 Wean Hall
Pittsburgh, Pennsylvania 15213-3890
Email rollett@andrew.cmu.edu
Phone 412-268-3177
Fax 412-268-7596
Anthony D. Rollett
June 24, 2015
To Whom It May Concern,
I am delighted to write on behalf of Suraj Rao and to very strongly
recommend him as a thoroughly professional and bright young engineer.
Suraj joined my group last September (2014) shortly after he started his
Masters program in the Materials Science & Engineering department at
CMU. I have become heavily involved in additive manufacturing and one
of the projects was a one-year effort in collaboration with Alcoa on 3D
printing of aluminum powders. I asked Suraj if he would like to
participate and he readily agreed. I directed him to learn about the
powder characterization techniques that other students in my group had
developed and apply them to the powders that Alcoa gave us to work
with. He quickly learned about transmission optical microscopy,
scanning electron microscopy, and image analysis (e.g. with ImageJ) and
was producing useful results within a few weeks. Part way through the
project we identified a serious discrepancy between our results and those
from Alcoa. Suraj worked with me to analyze this discrepancy, identify a
difference between number-based averaging and volume-based
averaging, re-process the data and report on the much improved
comparison. Subsequently we acquired several datasets of computed
tomography at the Advanced Photon Source (Argonne Natl. Lab.) on
samples of AM materials provided by Alcoa. The raw data then had to be
reconstructed into 3D images and the results analyzed for porosity
content. Suraj took charge of analyzing the 3D reconstructed images
(mainly with Avizo), which are so large that we had to purchase a state of
the art workstation with 225 gigabytes of RAM. Those images revealed
large variations in porosity as a function of processing conditions. He is
in the process of writing a paper on this work, which I expect will attract
substantial attention in the AM community because nobody has obtained
synchrotron data and analyzed it to the level of detail that we have here
at CMU. In terms of written communications, Suraj writes very well. In
terms of oral communication, I early on had him give presentations on
his work to the joint CMU-Alcoa team, which he did extremely well. He
comes across as pleasant, knowledgeable and professional. Altogether

2. he performed well above expectations and was a key member of the
project team. I fully expect him to be highly successful in whatever
situation he finds himself.
Sincerely,
Professor, Materials Science & Engineering
Brief bio: I have been a Professor of Materials Science and Engineering
at Carnegie Mellon University (CMU) since 1995. Previously, I worked for
the University of California at the Los Alamos National Laboratory. At
LANL, I spent ten years in management with five years as a Group
Leader (and then Deputy Division Director) at Los Alamos, followed by
five years as Department Head at CMU (1995-2000). I have been a
Fellow of ASM since 1996, Fellow of the Institute of Physics (UK) since
2004, and a Fellow of TMS since 2011. I received the Cyril Stanley Smith
Award for contributions to microstructural science from TMS in 2014.
My research group has about ten students and is supported by several
agencies including NIST, America Makes, DARPA, AFOSR, ONR, NSF, as
well as companies such as Alcoa, Boeing and Medtronic. The main focus
of my current research is on the measurement and prediction of
microstructural evolution, along with the relationship between
microstructure and properties, with a particular emphasis on three-
dimensional effects.