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Experience

Project Scientist

09 – Present                     University of California, San Diego, La Jolla, California

  • Science

    • Principal investigator of multiple NASA funded research projects, resulting in more than 10 first author research publications including 3 in Science Magazine and 3 in the Proceedings of the National Academy of Sciences (PNAS).

    • Wrote over 10 research grant proposals resulting in being awarded over $2.2 M research funds through NASA solicitations.

  • Project management of the NASA Genesis mission’s UCSD assignment which is to determine and analyze the composition of the sun and 5 other NASA funded projects to study the chemical evolution of our solar system.

    • Managed a budget of $2.2 M, communicated finance and policy to campus grant office, recruited research assistants, data interpretation, reporting to the funding agency and in technical conferences, publishing in peer-reviewed journals, managed data and developed accessibility protocol to comply with the funding agency.

  • Designed, prototyped, tested, arranged for the manufacturer, and deployed 3 complicated devices designed to do the following tasks:

    • Designed and partly fabricated an instrument to extract embedded solar wind particles in the Genesis (spacecraft) collector using a UV laser.

    • Designed and fabricated an integrated liquid nitrogen (LN2) cryostat and a chemical vapor deposition (CVD) unit to study the surface oxidation reactions possible in the astrophysical environment. The design of this apparatus was very conceptual where cooling of a substrate surface at LN2 temperature and operating a heater at 1600 C to evaporate rock samples inside a small vacuum chamber at the same time was needed. The biggest problem was that the high-temperature heater was heating the wall of the chamber and affecting the vacuum. This issue was solved by designing a water-flow cooling system. To know the lattice structure of the deposited thin film and the transformed mineral phases after oxidation, I inserted a TEM grid on top of the cold collection plate and performed TEM analysis afterward. To know the stoichiometry and I performed SEM/EDX analysis to image the minerals as well as the composition using an environment SEM, where the samples were directly loaded on SEM sample holder with double-sided tape.

    • Designed and fabricated a ‘coupling unit’ to introduce vacuum-UV light from an ultra-low vacuum synchrotron (Advanced Light Source, ALS) beamline into a gas-filled reaction chamber. The coupling was designed with a three-stage ‘differential pumping’ units internally connected through small apertures, thus the gas from high-pressure sides gradually gets pumped off in each stage and achieve high-vacuum were connected to the beamline. The apertures are aligned to introduce the photons inside the chamber.

 

  • Design 8 Original Standard Operating Procedures (SOPs) and safety protocols, implemented strategic safety protocols, trained employees to follow and reduce risk, waste, and costs

  • Designed and executed the following innovative experiments to simulate the condition of the solar nebula to understand the physics and chemistry of the solar system:

    • High-temperature gas-phase oxidation of silicates in nebular conditions to understand the oxygen isotopes in the meteorites. The major problem was to create silicon in the vapor phase. That problem was solved by adopting continuous laser ablation of the silicon substrate to create a steady-state gas-phase concentration inside a small vacuum chamber. Initially, the results are hard to understand and puzzling. To solve this, I have mathematically simulated the reactions by developing a Matlab code and was able to decipher different reaction channels. The results are published in Science, and we showed for the first time that symmetry dependent recombination reactions could produce meteorite-like mass-independent oxygen isotopic composition and a probable reaction in the solar nebula.

    • Simulation of the photochemical environment in the outer solar nebula to study the photochemical evolution of nitrogen using the vacuum-UV photons from ALS synchrotron. The results have implications for Titan’s and other planetary bodies and the formation of organic materials and are published in the Proceedings of the National Academy of Sciences. The major technical issue of this study was to capture the photochemically produced atomic nitrogen. The solution I have adopted is to mix hydrogen with the initial N2 gas. The product atomic-N, reacted with H­­2 and produced ammonia and was cryogenically collected. The next problem was to measure the N-isotopic composition in NH3 of the sub-micromole amount. This problem was tackled by producing break-seals for each sample separately with pre-conditioned CuO and later used high-temperature decomposition to liberate N2. Since the photon absorption cross-section of N2 at the VUV wavelengths are known, a Matlab based simulation code was developed to calculate the isotopic composition of the product nitrogen. These simulated values were in stark difference from the measured one and provided the most important clue to the chemical physics community about the lack of understanding of the photodissociation process.

    • Simulated the photochemical environment in the inner solar nebula to study the photochemical evolution of sulfur-bearing gas-H2S using the vacuum-UV photons from ALS synchrotron. The other major issue was to collect the H2S photolysis product, elemental sulfur. The experiments were performed with a chamber liner made from thick ultra-high purity Al-foil and the elemental sulfur was deposited on the foil and later treated the entire liner as a sample. The results are published in the Proceedings of the National Academy of Sciences, which show that the photochemically derived sulfur from H2S in the inner nebula was incorporated into the silicate phase and accreted as meteorite parent body.

    • Collected aerosol samples of a jet-exhaust from several locations on the runway to understand the isotopic composition of primary jet emission and its spatial and temporal evolution and the impact of synthetic fuels on commercial aircraft engines during “Alternative Aviation Fuel Experiment (AAFEX)” campaign. The major problem from the aerosol sample collection standpoint was to stabilize the high-volume filter units (made of aluminum) against the thrust of the jet exhaust. We solved this problem on-spot by adapting several modifications of the samplers using materials from the home improvement store, also we placed the samplers strategically to avoid the maximum thrust.

  • Mentored students, advised laboratory research associates for the smooth running of the projects.

  • High-impact research publications resulted in extensive national and international media coverage, including radio interviews and news articles.

       

Postdoctoral Researcher

2003 – 08                         University of California, San Diego   La Jolla, CA

  • Science

    • Principal Investigator of NASA funded research projects, resulted in high impact research publication in Science Magazine and was extensively covered by the national and international media, including newspaper interview and news articles. 

    • Written research grants resulted in over $ 750K research funds through NASA solicitations

    • Designed and executed experiments to simulate the photochemical environment of the early solar nebula inside a reaction chamber to study the oxygen isotopic composition from CO (major O-bearing gas in the nebula) photodissociation. The results are published in the journal Science, which shows the isotopic composition of the photochemically derived oxygen from CO.

  • Project management, starting from planning to recruiting undergraduate research assistants to execution, data interpretation, reporting to the funding agency and in technical conferences through oral and poster presentations, and finally publishing in peer-reviewed journals.

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Research Fellow

1998 – 03                         Physical Research Laboratory, Ahmedabad, India

  • Published 5 first author research articles in peer-reviewed journals.

  • I undertook a research problem to measure triple-isotopes of oxygen to understand the photochemical processes. To make this possible under limited resources I have converted an old dual collector mass-spectrometer to a triple collector one (suitable to measure all three isotopes of O2) with a bigger magnet. Designed a magnet positioning system to easily adjust the position of the magnet to get the perfectly focused beam. This extensive and innovative mass-spectrometric work resulted in ‘Best Thesis of the Year Award, 2003’ from the Indian Society for Mass-spectrometry (ISMAS).  

 

Project Associate

1996 – 98                         Physical Research Laboratory, Ahmedabad, India

  • Assigned to a job to design and fabricate an ultra-low background gamma counter to quantify low-level radioactivity in fresh fall meteorites. Two detectors were used inside a lead-shield in anti-coincidence to filter the actual signal from the sample from the background. The challenge was to build a mechanism to lift one of the detectors (~60 lbs.) during changing the samples. I built a pulley system made from a certain kind of hard plastic with zero-background (had to test each material before using) and finally, it was a success.

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