The mass of 15B via a three-proton stripping reaction

The isotope ¹⁵B was produced via the reaction ⁴⁸Ca(¹⁸O, ¹⁵B)⁵¹V. The Q-value and mass excess were determined to be ?21.76 ± 0.05 MeV and 28.96 ± 0.05 MeV, respectively. A search for the isotope ¹⁴Be was unsuccessful.     

Homogenization and Enhancement for the G—Equation

We consider the so-called G-equation, a level set Hamilton–Jacobi equation used as a sharp interface model for flame propagation, perturbed by an oscillatory advection in a spatio-temporal periodic environment. Assuming that the advection has suitably small spatial divergence, we prove that, as the size of the oscillations diminishes, the solutions homogenize (average out) and converge to the solution of an effective anisotropic first-order (spatio-temporal homogeneous) level set equation. Moreover, we obtain a rate of convergence and show that, under certain conditions, the averaging enhances the velocity of the underlying front. We also prove that, at scale one, the level sets of the solutions of the oscillatory problem converge, at long times, to the Wulff shape associated with the effective Hamiltonian. Finally, we also consider advection depending on position at the integral scale.     

Variational principle and reaction-diffusion front speeds in random flows

We summarize recent advances of analyzing Kolmogorov-Petrovsky-Piskunov (KPP) fronts in random compressible and incompressible flows. In particular, a long standing open problem of the existence and characterization of the so called turbulent flame speed is resolved for KPP fronts in space-time random incompressible flows under certain regularity and moment conditions on the flow fields. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)