The Square Kilometre Array (SKA) is a planned large radio interferometer designed to operate over a wide range of frequencies, and with an order of magnitude greater sensitivity and survey speed than any current radio telescope. The SKA will address many important topics in astronomy, ranging from planet formation to distant galaxies. However, in this work, we consider the perspective of the SKA as a facility for studying physics. We review four areas in which the SKA is expected to make major contributions to our understanding of fundamental physics: cosmic dawn and reionisation; gravity and gravitational radiation; cosmology and dark energy; and dark matter and astroparticle physics. These discussions demonstrate that the SKA will be a spectacular physics machine, which will provide many new breakthroughs and novel insights on matter, energy, and spacetime.

Supersonic civil aircraft present a unique noise certification challenge. High specific thrust required for supersonic cruise results in high engine exhaust velocity and high levels of jet noise during take-off. Aerodynamics of thin, low-aspect-ratio wings equipped with relatively simple flap systems deepen the challenge. Advanced noise reduction procedures have been proposed for supersonic aircraft. These procedures promise to reduce certification noise levels, but they may require departures from normal reference procedures defined in noise regulations. The subject of this article is a take-off performance and noise assessment of a notional supersonic business jet. Analytical models of an airframe and a supersonic engine derived from a contemporary subsonic turbofan core are developed. These models are used to predict take-off trajectories and certification noise levels. Results indicate advanced take-off procedures are helpful in reducing noise along lateral sidelines.

We present a new semi–analytic treatment of the evolution of galactic winds within high resolution, large scale cosmological N–body simulations of a $\Lambda$CDM Universe. We focus our analysis on the impact of winds on the diffuse intergalactic medium at $z=3$ and we make predictions for the volume filling factor of winds as a function of our model parameters. We then verify this prediction by extracting a set of synthetic spectra along random lines of sight through our simulated box and by calculating the probability distribution function (PDF) of the spectral flux. We find that galactic winds do not significantly modify the PDF. We finally argue that the increased flux transmissivity found by Adelberger et al. (2003) around a small sample of Lyman break galaxies may be explained by the presence of hot ionised bubbles due to pressure–driven winds outflowing from the galaxies. However, this effect cannot be explained by cooled, momentum–driven winds. We conclude that the result of Adelberger et al. (2003) may be the outcome of a selection effect.

Low temperature monochromatic cathodoluminescence (CL) spectral analyses and imaging were used to determine the widths of resistive regions (due to Fe diffusion) in multi-quantum-well (MQW) InP-based laser devices and to detect the different amount of damage induced by alternative In-situ Etching (ISE) and Reactive Ion Etching (RIE) techniques. The widths of the resistive regions were estimated by comparing the 5 K CL emission width from the MQW and the actual width as obtained by SEM investigations. Monochromatic CL also did not reveal any emission from the InP:Sn layer between semi-insulating material (Fe-doped lnp) and p-type layer (Zn-doped InP), indicating interdiffusion of Fe and Zn laterally the MQW, and the presence of substantial Sn diffusion (up to 2500 nanometers) into the substrate.