Noise Reduction in Millisecond Pulsar Timing

Astronomers use pulsars as astronomical clocks to perform physical tests, such as in testing Einstein\u27s Theory of General Relativity. As these tests require more precise clock time measurements, we run into problems associated with the pulses traveling through particles in space. Using data taken simultaneously at two radio telescopes, we looked to improve the precision of measurements taken of two pulsars. We looked for correlations between data sets using a variety of techniques to account for the error in our measurements. We report our results in the hopes that these methods can be used in future pulsar timings

Shape optimization for surface functionals in Navier--Stokes flow using a phase field approach

We consider shape and topology optimization for fluids which are governed by the Navier--Stokes equations. Shapes are modelled with the help of a phase field approach and the solid body is relaxed to be a porous medium. The phase field method uses a Ginzburg--Landau functional in order to approximate a perimeter penalization. We focus on surface functionals and carefully introduce a new modelling variant, show existence of minimizers and derive first order necessary conditions. These conditions are related to classical shape derivatives by identifying the sharp interface limit with the help of formally matched asymptotic expansions. Finally, we present numerical computations based on a Cahn--Hilliard type gradient descent which demonstrate that the method can be used to solve shape optimization problems for fluids with the help of the new approach