Tyler Anderson

Toward Distinct Element Method Simulations of Carbon Nanotube Systems

We propose distinct element method modeling of carbon nanotube systems. The atomiclevel description of an individual nanotube is coarse-grained into a chain of spherical elements that interact by parallel bonds located at their contacts. The spherical elements can lump multiple translational unit cells of the carbon nanotube and have both translational and rotational degrees of freedom. The discrete long ranged interaction between nanotubes is included in a van der Waals contact of nonmechanical nature that acts simultaneously with the parallel bonds. The created mesoscopic model is put into service by simulating a realistic carbon nanotube ring. The ring morphology arises from the energy balance stored in both parallel and van der Waals bonds. DOI: 10.1115/1.4002609

Re-measurement of the S33(α,p)Cl36 cross section for early solar system nuclide enrichment

Short-lived radionuclides (SLRs) with half-lives less than 100 Myr are known to have existed around the time of the formation of the solar system around 4.5 billion years ago. Understanding the production sources for SLRs is important for improving our understanding of processes taking place just after solar system formation as well as their timescales. Early solar system models rely heavily on calculations from nuclear theory due to a lack of experimental data for the nuclear reactions taking place. In 2013, Bowers et al. measured

Activity measurement of Fe60 through the decay of Co60m and confirmation of its half-life

{}^{36}

Re-measurement of the

Cl production cross sections via the

{}^{33}

{}^{33}

S(

S(

\alpha

\alpha

,p)

,p) reaction and reported cross sections that were systematically higher than predicted by Hauser-Feshbach codes. Soon after, a paper by Peter Mohr highlighted the challenges the new data would pose to current nuclear theory if verified. The

{}^{36}

{}^{33}

Cl cross section for Early solar system enrichment

S(