The Debate of Immigration: Democracy, Autonomy, and Coercion

This discussion looks at immigration through philosophical debates of democracy, coercion, and autonomy. There seems to be a fundamental contradiction between democratic state\u27s border control and democratic legitimacy. First, I discuss the democratic legitimacy and the need for democratic justifications with the invasion of autonomy.Then, I discuss Arash Abizadeh\u27s argument that border control is coercive and invades personal autonomy, and David Miller\u27s response that border control does not amount to coercion, but is prevention. I conclude border control invades autonomy even if it is not coercive, and thus, democratic justifications are needed. Ultimately, I suggest that open borders should be encouraged because it is the better alternative to what is required of democratic justification for close borders

Surface wave modelling and simulation for wave tanks and coastal areas

For testing ships and offshore structures in hydrodynamic laboratories, the sea and ocean states should be represented as realistic as possible in the wave tanks in which the scaled experiments are executed. To support efficient testing, accurate software that determines and translates the required wave maker motion into the downstream waves is very helpful. This paper describes an efficient hybrid spatial-spectral code that can deal with simulations above flat and varying bottom. The accuracy of the code will be illustrated by presenting comparisons of simulations with experimental data for various different type of non-breaking waves, from dispersive focussing waves to irregular wave fields with freak waves; the very broad-band spectra of such waves provide the main challeng

Propagation of wave groups over bathymetry using a variational Boussinesq model

Surface water waves propagating into shallow water are affected by the changes in the sea bed. Often, Boussinesq-type wave models are used to take these finite-depth effects into account. In Klopman et al. (2005), a variational method has been used to derive fully non-linear Boussinesq-type models from the full three-dimensional Hamiltonian structure. Th

A variational model for fully non-linear water waves of Boussinesq type

Using a variational principle and a parabolic approximation to the vertical structure of the velocity potential, the equations of motion for surface gravity waves over mildly sloping bathymetry are derived. No approximations are made concerning the non-linearity of the waves. The resulting model equations conserve mass, momentum and positive-definite energy. They are shown to have improved frequency-dispersion characteristics, as compared to classical Boussinesq-type of wave equations

A combination of Dirichlet to Neumann operators and perfectly matched layers as boundary conditions for optical finite element simulations

By combining Dirichlet to Neumann (DtN) operators and Perfectly Matched Layers (PML’s) as boundary conditions on a rectangular domain on which the Helmholtz equation is solved, the disadvantages of both methods are greatly diminished. Due to the DtN operators, light may be accurately fluxed into the domain, while the PML’s absorb light that is reflected from the corners of the domain when only DtN boundaries are used

Angle-resolved cathodoluminescence imaging polarimetry

Cathodoluminescence spectroscopy (CL) allows characterizing light emission in bulk and nanostructured materials and is a key tool in fields ranging from materials science to nanophotonics. Previously, CL measurements focused on the spectral content and angular distribution of emission, while the polarization was not fully determined. Here we demonstrate a technique to access the full polarization state of the cathodoluminescence emission, that is the Stokes parameters as a function of the emission angle. Using this technique, we measure the emission of metallic bullseye nanostructures and show that the handedness of the structure as well as nanoscale changes in excitation position induce large changes in polarization ellipticity and helicity. Furthermore, by exploiting the ability of polarimetry to distinguish polarized from unpolarized light, we quantify the contributions of different types of coherent and incoherent radiation to the emission of a gold surface, silicon and gallium arsenide bulk semiconductors. This technique paves the way for in-depth analysis of the emission mechanisms of nanostructured devices as well as macroscopic media.Comment: 8 figures. Includes supplementary informatio