A5059169335- Nuclear physics research studies
- Astro and Planetary Science
- Astronomical and nuclear sciences
- Gamma-ray bursts and supernovae
- Atomic and Molecular Physics
- Stellar, planetary, and galactic studies
- Nuclear Physics and Applications
- Astrophysical Phenomena and Observations
- Planetary Science and Exploration
- Material Dynamics and Properties
- Atomic and Subatomic Physics Research
- Radiation Detection and Scintillator Technologies
- Polymer Nanocomposites and Properties
- Nuclear reactor physics and engineering
- Electrohydrodynamics and Fluid Dynamics
- High-pressure geophysics and materials
- Rare-earth and actinide compounds
- Spacecraft and Cryogenic Technologies
- Polymer crystallization and properties
- Experimental and Theoretical Physics Studies
- Carbon Nanotubes in Composites
- Superconducting Materials and Applications
- Neutrino Physics Research
- Gold and Silver Nanoparticles Synthesis and Applications
- Coagulation and Flocculation Studies
University of North Carolina at Chapel Hill
2010-2023
Triangle Universities Nuclear Laboratory
2010-2023
Duke University
2017-2022
North Carolina State University
2008-2011
North Central State College
2011
Hydrogen burning of the oxygen isotopes takes place in low-mass stars, asymptotic giant branch and classical novae. Observations elemental isotopic abundances stellar spectra or presolar grains provide strong constraints for models if reliable thermonuclear reaction rates hydrogen are available. We present results a new measurement ${}^{17}\mathrm{O}{(p,\ensuremath{\gamma})}^{18}\mathrm{F}$ laboratory bombarding energy range $170--530$ keV. The is performed with significantly higher beam...
Classical novae are stellar explosions occurring in binary systems, consisting of a white dwarf and main-sequence companion. Thermonuclear runaways on the surface massive dwarfs, oxygen neon, believed to reach peak temperatures several hundred million kelvin. These strongly correlated with underlying mass. The observational counterparts such models likely associated outbursts that show strong spectral lines neon their shells (neon novae). goals this work investigate how useful elemental...
The $^{22}\mathrm{Ne}(p,\ensuremath{\gamma})^{23}\mathrm{Na}$ reaction is one of the most uncertain reactions in NeNa cycle and plays a crucial role creation $^{23}\mathrm{Na}$, only stable Na isotope. Uncertainties low-energy rates this other lead to ambiguities nucleosynthesis predicted from models thermally pulsing asymptotic giant branch (AGB) stars. This turn complicates interpretation anomalous Na-O trends globular cluster evolutionary scenarios. Previous studies...
Classical novae are caused by mass transfer episodes from a main-sequence star onto white dwarf via Roche lobe overflow. This material possesses angular momentum and forms an accretion disk around the dwarf. Ultimately, fraction of this spirals in piles up on surface under electron-degenerate conditions. The subsequently occurring thermonuclear runaway reaches hundreds megakelvin explosively ejects matter into interstellar medium. exact peak temperature strongly depends underlying mass,...
About 30% to 40% of classical novae produce dust 20-100 days after the outburst, but no presolar stardust grains from have been unambiguously identified yet. Although several studies claimed a nova paternity for certain grains, measured and simulated isotopic ratios could only be reconciled assuming that condensed ejecta mixed with much larger amount close-to-solar matter. However, source mechanism this potential post-explosion dilution remains mystery. A major problem previous is small...
The ${E}_{\ensuremath{\alpha}}^{\text{lab}}=0.83$ MeV resonance in the $^{22}\mathrm{Ne}(\ensuremath{\alpha},\ensuremath{\gamma})^{26}\mathrm{Mg}$ reaction strongly impacts rates stellar temperature region crucial for astrophysical s process. We report on a new measurement of energy and strength this using techniques different from previous investigations. use blister-resistant $^{22}\mathrm{Ne}$-implanted target employ $\ensuremath{\gamma}\ensuremath{\gamma}$-coincidence detection...
Monte Carlo simulations of finite-size effects for continuum percolation in three-dimensional, rectangular sample spaces filled with spherical particles were performed. For samples any dimension less than 10-20 times the particle diameter, observed. thin films regime, across direction film gave critical volume fraction (p(c)) values that differed from those along plane film. Simulations perpendicular to very resulted p(c) lower classical limit ∼29% (for spheres a three-dimensional matrix)...
The development of nanocomposites (a matrix, often polymeric, enhanced by a particle with nanometer-sized dimension) has expanded dramatically in recent years particular focus on materials complex microstructure and nanostructure. Such composites rely formation connected network particles throughout the sample volume order to enhance polymer's mechanical electrical properties. From fundamental perspective, this will be governed percolation process within constrained geometry microstructure....
The thermonuclear rate of the $^{29}\mathrm{Si}(p,\ensuremath{\gamma})^{30}\mathrm{P}$ reaction impacts $^{29}\mathrm{Si}$ abundance in classical novae. A reliable is essential for testing nova paternity presolar stardust grains. At present, fact that no grains have been unambiguously identified primitive meteorites among thousands studied puzzling, considering novae are expected to be prolific producers dust We investigated $^{29}\mathrm{Si}+p$ at center-of-mass energies...
Presolar stardust grains found in primitive meteorites are believed to retain the isotopic composition of stellar outflows at time grain condensation. Therefore, laboratory measurements their ratios represent sensitive probes for investigating open questions related evolution, explosions, nucleosynthesis, mixing mechanisms, dust formation, and galactic chemical evolution. For a few selected presolar grains, classical novae have been discussed as potential source. SiC, silicate, graphite...