Ph.D. student makes advances in materials science at NIOSH

Kabir Rishi, a doctoral student in materials science at the University of Cincinnati, was named Graduate Student Engineer of the Month by the College of Engineering and Applied Science.

Here, Rishi shares his experience working in the automotive hydraulics industry in India and outlines his research work studying industrial nanoparticles to make better and safer products, including his current work at the National Institute for Occupational Safety and Health (NIOSH) in the Centers for Disease Control and Prevention. 

I was involved with product development and materials management of automotive hydraulics. I synergized product design and manufacturing constraints, addressed product quality issues, strategically sourced parts from suppliers while building their capability and localized manufacturing to improve the bottom line. Throughout my three years in this role, I was driven by the need to understand the product-performance relationship at a more fundamental level, so a Ph.D. in materials science was an obvious choice.

The science of materials — their structure, interactions and arrangement on the atomic to the mesoscale — were more than mere fascination to me. To my mechanical brain, this science is at the core of how everything works. Understanding the science and then being able to tune the structure to develop improved products drew me to this field.

My research is centered on characterizing industrial nanoparticles in commercially relevant products such as automotive tires, printer inks and lithium-ion batteries through X-ray scattering at synchrotron facilities in the U.S. I quantify the morphology of these particles across various size scales, assess how they disperse in polymer matrices and establish new structure-property relationships.

I believe that with a deeper understanding of the structure, the properties of these commercial products can be tuned for more specific applications. For example, better automotive tires could offer better fuel efficiency and road safety.  

Although the use of nanoparticles in commercial products offers significant improvements and tuning the structure would result in more advanced applications, the health risks associated with the exposure of these nanoparticles to the field workers during production can be adverse. My current research is focused on precisely quantifying workplace emissions through X-rays and other spectroscopic techniques to ensure that they meet the regulatory norms.

I am completing my curricular practical training at NIOSH. My research is centered toward advancing the quantification methodology for industrial particulate emissions and aerosol science is the field I hope to contribute towards in future. I intend on continuing at NIOSH as a post-doctoral researcher after I complete my Ph.D. at UC. 

As a peer tutor at the learning assistance center at UC, I tutored math and science courses to undergraduate engineering students. Mathematics is one course that most students find challenging which perhaps prevents them from opting for engineering majors. My advice to prospective students is to look at mathematics as a language, a form of expression rather than inscrutable hieroglyphs. More importantly, read the oft ignored first page of the recommended textbook that contains examples of how the contents of the particular chapter are used in everyday life. I believe that once one starts seeing how mathematical equations are applied from video games to predicting the near future, engineering could become easier. Also, the Math and Science Support (MASS) Center at UC is a wonderful resource for undergraduates, and I highly recommend that students use it.

As a senior graduate student in my research group, I have mentored eight undergraduate students and two are now pursuing Ph.D. programs in polymers and materials science. Another two intend on applying for graduate programs. As a math and science tutor, I learned to work with a diverse group of students with different acumen and learning styles. To see that I could adapt and deliver the best possible ways to aid in their success was very empowering. Additionally, UC’s impetus towards applied research enabled me to collaborate with scientists and engineers in the industry as well as national laboratories.

I was one of the first to couple nano-structure as observed in TEM, small-angle X-ray and neutron scattering, and in modeling with dynamics using oscillatory rheometry for complex systems such as filled elastomers and worm-like micelles. I also made significant contributions to understanding the nature of structural organization of nanoparticles in polymer nanocomposites by developing scattering functions that describe correlated and non-correlated systems. I also pioneered the use of a modified van der Waals equation of state to describe kinetic dispersion of nanomaterials which has seen success in describing the impact of processing conditions on nano scale dispersion.  I also worked with a visiting scientist from the Max Planck Institute in Berlin, Karsten Vogtt, to develop and demonstrate a new thermodynamic model for equilibrium hierarchical structures such as worm-like micelles or organic pigments in surfactant stabilized aqueous dispersions. 

Featured image at top: Abstract illustration of nanoparticles. Photo/GiroScience/Shutterstock.