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Astrophysical x-ray bursts are thought to be a result of thermonuclear explosions on the atmosphere of an accreting neutron star. Between these bursts, energy is thought to be generated by the hot CNO cycles. The O-15(alpha,gamma)Ne-19 reaction is one reaction that allows breakout from these CNO cycles and into the rp-process to fuel outbursts. The reaction is expected to be dominated by a single 3/2(+) resonance at 4.033 MeV in Ne-19, however, limited information is available on this key state. This work reports on a pioneering study of the Ne-20(p, d)Ne-19 reaction, performed in inverse kinematics at the experimental storage ring (ESR) as a means of accessing the astrophysically important 4.033 MeV state in Ne-19. The unique, background free, high luminosity conditions of the storage ring were utilized for this, the first transfer reaction performed at the ESR. The results of this pioneering test experiment are presented along with suggestions for future measurements at storage ring facilities.

An analytical model for the electrothermomechanical analysis of out-of-plane deformation in resistively heated single-stepped beams is presented. The model takes into account the conductive heat transfer from the beam to the substrate in which it is anchored. It also considers the temperature dependence of the beam material properties and accounts for the locally enhanced resistive heating effect around the release holes in the beam to predict temperature distribution along the beam. Energy method and Euler–Bernoulli beam theory are used for the prediction of out-of-plane deformation and stress distribution of the beam, as well as the out-of-plane rotation at the middle of the beam. The model considers the nonuniformity of the air gap between the beam and the substrate and captures the resultant asymmetric temperature distribution along the beam. The out-of-plane rotations in the middle of the single-stepped beam predicted by the analytical model and measured experimentally agree within 10%. The analytical model is then used to predict the maximum actuation current, which results in high temperature plastic deformation and agrees with the experiments within 5%. The proposed analytical model provides a good approach for systematic design and analysis of out-of-plane electrothermal microactuators based on single-stepped beam design.

Thermal sensitivity of bi-material microcantilevers plays a crucial role in temperature sensors and thermal actuators. Thermal loading experiments on bi-material microcantilevers show the dependence of thermal sensitivity on microcantilever curvature and width which is not addressed by currently used analytical models. In this work, a new thermal sensitivity model for curved bi-material microcantilevers is presented which correlates such dependence to the increase of microcantilever flexural rigidity caused by transverse curvature. The new model is validated against the results of thermal loading experiments carried out on gold-polysilicon and SU-8/silicon nitride bi-material microcantilevers with different widths and initial curvatures.

A recently developed theory of stochastic swimming is used to study the notion of coherence in active systems that couple via hydrodynamic interactions. It is shown that correlations between various modes of deformation in stochastic systems play the same role as the relative internal phase in deterministic systems. An example is presented where a simple swimmer can use these correlations to hunt a non-swimmer by forming a hydrodynamic bound state of tunable velocity and equilibrium separation. These results highlight the significance of coherence in the collective behavior of nano-scale stochastic swimmers., Comment: 6 pages, 3 figures