A5070035770- Gas Dynamics and Kinetic Theory
- Astro and Planetary Science
- Planetary Science and Exploration
- Advanced MEMS and NEMS Technologies
- Mechanical and Optical Resonators
- Spacecraft Design and Technology
- Geology and Paleoclimatology Research
- Nuclear and radioactivity studies
- Graphite, nuclear technology, radiation studies
- Meteorological Phenomena and Simulations
- Plasma and Flow Control in Aerodynamics
- Genetic Neurodegenerative Diseases
- Photonic and Optical Devices
- Space Science and Extraterrestrial Life
- Fluid Dynamics and Turbulent Flows
- Vehicle emissions and performance
- Various Chemistry Research Topics
- Space Exploration and Technology
- Combustion and Detonation Processes
- Geophysics and Gravity Measurements
- Spacecraft and Cryogenic Technologies
- Radiation Effects in Electronics
Purdue University West Lafayette
2012-2018
American Institute of Aeronautics and Astronautics
2011
Abstract Major impact events have shaped the Earth as we know it. The Late Heavy Bombardment is of particular interest because it immediately precedes first evidence life. reentry ejecta creates numerous chemical by‐products, including biotic precursors such HCN. This work examines production HCN during in more detail. We stochastically simulate range impacts on early and use models developed from existing studies to predict corresponding properties. Using multiphase flow methods finite‐rate...
Abstract The Chicxulub impact 66.0 Ma ago initiated the second biggest extinction in Phanerozoic Eon. cause of concurrent oceanic nitrogen isotopic anomaly, however, remains elusive. impactor struck Yucatán peninsula, ejecting 2 × 10 15 kg molten and vaporized rock that reentered globally as approximately 23 microscopic spherules. Here we report modern techniques indicate this ejecta generates 1.5 14 moles NO x , which is enough to observed enrichment basal layer. Additionally, reentry‐based...
This paper introduces and experimentally validates a new model for near-contact gas damping of microbeams. The is formulated based on numerical simulations rarefied dynamics using the Boltzmann Ellipsoidal Statistical Bhatnagar-Gross-Krook (ES-BGK) equation. result compared with existing models by simulating motion beams under high-g acceleration. To validate models, single crystal silicon MEMS g-switches cantilever microbeams various lengths were utilized. experimental measurements beam...
Major impact events have drastically altered the evolution of life on Earth. The reentry ejecta formed from these can trigger widespread chemical changes to atmosphere a global scale. This mechanism was proposed as source HCN during Late Heavy Bombardment (LHB), 4.1 3.8 billion years ago. Significant concentrations in surface water could directly lead adenine formation, precursor for RNA. work uses Direct Simulation Monte Carlo (DSMC) method examine production CN and due ejecta. We use...
Examining the short and long term effects of Chicxulub impact is critical for understanding how life developed on Earth. While aftermath initial would have produced harmful levels radiation sufficient eradicating a large portion terrestrial life, this process does not explain concurrent marine extinction. Following primary impact, quantity smaller spherules de-orbit re-enter earths atmosphere, dispersed nearly uniformly across planet. This secondary wave debris at high velocities, altering...
This paper presents the first near-contact aerodynamic damping model based on rarefied flow modeling for use in dynamic simulations of large-displacement motion and contacting behavior microbeams. The is constructed high-fidelity gas around microbeams Boltzmann kinetic equation with Ellipsoidal Statistical Bhatnagar-Gross-Krook (ES-BGK) collision relaxation model. predictions using new previously published models are compared experimentally measured responses silicon under a high-g load....